Harden a vestigial check against overflow inside png_zalloc

Reported-by: Sergio Atienza Pastor, MTP Métodos y Tecnología

.gitignore

@@ -122,6 +122,7 @@ ipch/
 *.out
 *out.png
 [._]deps/
+[._]libs/
 .dirstamp
 /Makefile
 /autom4te.cache/
@@ -143,13 +144,16 @@ pnglibconf.dfn
 pnglibconf.pre
 pngprefix.h
 
-# Libpng test programs
-png-fix-itxt
-pngcp
-pngfix
-pngimage
-pngstest
-pngtest
-pngunknown
-pngvalid
-timepng
+# Libpng test programs, scripts and artifacts
+/test-suite.log
+/tests/*.log
+/tests/*.trs
+/png-fix-itxt
+/pngcp
+/pngfix
+/pngimage
+/pngstest
+/pngtest
+/pngunknown
+/pngvalid
+/timepng

ANNOUNCE

@@ -1,5 +1,13 @@
-libpng 1.6.49 - June 12, 2025
-=============================
+libpng 1.6.51.git
+=================
+
+This is a development version, not intended to be a public release.
+It will be replaced by a public release, or by another development
+version, at a later time.
+
+
+libpng 1.6.50 - July 1, 2025
+============================
 
 This is a public release of libpng, intended for use in production code.
 
@@ -9,13 +17,13 @@ Files available for download
 
 Source files with LF line endings (for Unix/Linux):
 
- * libpng-1.6.49.tar.xz (LZMA-compressed, recommended)
- * libpng-1.6.49.tar.gz (deflate-compressed)
+ * libpng-1.6.50.tar.xz (LZMA-compressed, recommended)
+ * libpng-1.6.50.tar.gz (deflate-compressed)
 
 Source files with CRLF line endings (for Windows):
 
- * lpng1649.7z (LZMA-compressed, recommended)
- * lpng1649.zip (deflate-compressed)
+ * lpng1650.7z (LZMA-compressed, recommended)
+ * lpng1650.zip (deflate-compressed)
 
 Other information:
 
@@ -25,13 +33,18 @@ Other information:
  * TRADEMARK.md
 
 
-Changes from version 1.6.48 to version 1.6.49
+Changes from version 1.6.49 to version 1.6.50
 ---------------------------------------------
 
- * Added SIMD-optimized code for the RISC-V Vector Extension (RVV).
-   (Contributed by Manfred Schlaegl, Dragos Tiselice and Filip Wasil)
- * Added various fixes and improvements to the build scripts and to
-   the sample code.
+ * Improved the detection of the RVV Extension on the RISC-V platform.
+   (Contributed by Filip Wasil)
+ * Replaced inline ASM with C intrinsics in the RVV code.
+   (Contributed by Filip Wasil)
+ * Fixed a decoder defect in which unknown chunks trailing IDAT, set
+   to go through the unknown chunk handler, incorrectly triggered
+   out-of-place IEND errors.
+   (Contributed by John Bowler)
+ * Fixed the CMake file for cross-platform builds that require `libm`.
 
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net.

CHANGES

@@ -6267,6 +6267,19 @@ Version 1.6.49 [June 12, 2025]
   Added various fixes and improvements to the build scripts and to
     the sample code.
 
+Version 1.6.50 [July 1, 2025]
+  Improved the detection of the RVV Extension on the RISC-V platform.
+    (Contributed by Filip Wasil)
+  Replaced inline ASM with C intrinsics in the RVV code.
+    (Contributed by Filip Wasil)
+  Fixed a decoder defect in which unknown chunks trailing IDAT, set
+    to go through the unknown chunk handler, incorrectly triggered
+    out-of-place IEND errors.
+    (Contributed by John Bowler)
+  Fixed the CMake file for cross-platform builds that require `libm`.
+
+Version 1.6.51 [TODO]
+
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net.
 Subscription is required; visit
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement

CMakeLists.txt

@@ -18,9 +18,9 @@ cmake_minimum_required(VERSION 3.14...4.0)
 
 set(PNGLIB_MAJOR 1)
 set(PNGLIB_MINOR 6)
-set(PNGLIB_REVISION 49)
-set(PNGLIB_SUBREVISION 0)
-#set(PNGLIB_SUBREVISION "git")
+set(PNGLIB_REVISION 51)
+#set(PNGLIB_SUBREVISION 0)
+set(PNGLIB_SUBREVISION "git")
 set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_REVISION})
 set(PNGLIB_ABI_VERSION ${PNGLIB_MAJOR}${PNGLIB_MINOR})
 set(PNGLIB_SHARED_VERSION ${PNGLIB_ABI_VERSION}.${PNGLIB_REVISION}.${PNGLIB_SUBREVISION})
@@ -30,6 +30,7 @@ project(libpng
         LANGUAGES C ASM)
 
 include(CheckCSourceCompiles)
+include(CheckLibraryExists)
 include(GNUInstallDirs)
 
 # Allow the users to specify an application-specific API prefix for libpng
@@ -138,19 +139,15 @@ endif()
 
 # Find the zlib library.
 find_package(ZLIB REQUIRED)
+set(PNG_LINK_LIBRARIES ZLIB::ZLIB)
 
-# Find the math library (where available).
-if(UNIX
-   AND NOT (APPLE OR BEOS OR HAIKU)
-   AND NOT EMSCRIPTEN)
-  find_library(M_LIBRARY m)
-  if(M_LIBRARY)
-    set(M_LIBRARY m)
-  else()
-    set(M_LIBRARY "")
+# Find the math library (unless we already know it's not available or
+# not needed).
+if(UNIX AND NOT (APPLE OR BEOS OR HAIKU OR EMSCRIPTEN))
+  check_library_exists(m pow "" PNG_HAVE_LIBM_POW)
 endif()
-else()
-  # libm is not available or not needed.
+if(PNG_HAVE_LIBM_POW)
+  list(APPEND PNG_LINK_LIBRARIES m)
 endif()
 
 # Silence function deprecation warnings on the Windows compilers that might
@@ -322,26 +319,40 @@ if(PNG_HARDWARE_OPTIMIZATIONS)
   # Set definitions and sources for RISC-V.
   if(PNG_TARGET_ARCHITECTURE MATCHES "^(riscv)")
     include(CheckCCompilerFlag)
-    set(PNG_RISCV_RVV_POSSIBLE_VALUES check on off)
+    set(PNG_RISCV_RVV_POSSIBLE_VALUES on off)
     set(PNG_RISCV_RVV "off"
-      CACHE STRING "Enable RISC-V Vector optimizations: check|on|off; off is default")
+      CACHE STRING "Enable RISC-V Vector optimizations: on|off; off is default")
     set_property(CACHE PNG_RISCV_RVV
                 PROPERTY STRINGS ${PNG_RISCV_RVV_POSSIBLE_VALUES})
     list(FIND PNG_RISCV_RVV_POSSIBLE_VALUES ${PNG_RISCV_RVV} index)
     if(index EQUAL -1)
       message(FATAL_ERROR "PNG_RISCV_RVV must be one of [${PNG_RISCV_RVV_POSSIBLE_VALUES}]")
     elseif(NOT PNG_RISCV_RVV STREQUAL "off")
-      check_c_compiler_flag("-march=rv64gv1p0" COMPILER_SUPPORTS_RVV)
+
+      check_c_source_compiles("
+        #include <riscv_vector.h>
+        #include <asm/hwcap.h>
+        #ifndef COMPAT_HWCAP_ISA_V /* added in linux-6.5 */
+        #error \"COMPAT_HWCAP_ISA_V is not available\"
+        #endif
+        int main() {
+          const float src[] = { 0.0f, 0.0f, 0.0f, 0.0f };
+          uint64_t ptr[2] = {0x0908060504020100, 0xFFFFFFFF0E0D0C0A};
+          vuint8m1_t a = __riscv_vreinterpret_v_u64m1_u8m1(__riscv_vle64_v_u64m1(ptr, 2));
+          vfloat32m1_t val = __riscv_vle32_v_f32m1((const float*)(src), 4);
+          return (int)__riscv_vfmv_f_s_f32m1_f32(val);
+      }" COMPILER_SUPPORTS_RVV)
+
       if(NOT COMPILER_SUPPORTS_RVV)
-        message(FATAL_ERROR "Compiler does not support -march=rv64gv1p0 option")
+        message(FATAL_ERROR "Compiler does not support RISC-V Vector extension or its unable to detect it")
       endif()
       set(libpng_riscv_sources
           riscv/filter_rvv_intrinsics.c
           riscv/riscv_init.c)
       if(PNG_RISCV_RVV STREQUAL "on")
         add_definitions(-DPNG_RISCV_RVV_OPT=2)
-      elseif(PNG_RISCV_RVV STREQUAL "check")
-        add_definitions(-DPNG_RISCV_RVV_CHECK_SUPPORTED)
+      else()
+        add_definitions(-DPNG_RISCV_RVV_OPT=0)
       endif()
     else()
       add_definitions(-DPNG_RISCV_RVV_OPT=0)
@@ -688,7 +699,7 @@ if(PNG_SHARED)
                              SYSTEM
                              INTERFACE "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/libpng${PNGLIB_ABI_VERSION}>")
   target_link_libraries(png_shared
-                        PUBLIC ZLIB::ZLIB ${M_LIBRARY})
+                        PUBLIC ${PNG_LINK_LIBRARIES})
 endif()
 
 if(PNG_STATIC)
@@ -706,7 +717,7 @@ if(PNG_STATIC)
                              SYSTEM
                              INTERFACE "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/libpng${PNGLIB_ABI_VERSION}>")
   target_link_libraries(png_static
-                        PUBLIC ZLIB::ZLIB ${M_LIBRARY})
+                        PUBLIC ${PNG_LINK_LIBRARIES})
 endif()
 
 if(PNG_FRAMEWORK AND NOT APPLE)
@@ -739,7 +750,7 @@ if(PNG_FRAMEWORK)
                              SYSTEM
                              INTERFACE "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/libpng${PNGLIB_ABI_VERSION}>")
   target_link_libraries(png_framework
-                        PUBLIC ZLIB::ZLIB ${M_LIBRARY})
+                        PUBLIC ${PNG_LINK_LIBRARIES})
 endif()
 
 if(NOT PNG_LIBRARY_TARGETS)
@@ -936,7 +947,7 @@ if(PNG_SHARED AND PNG_TOOLS)
 
   add_executable(png-fix-itxt ${png_fix_itxt_sources})
   target_link_libraries(png-fix-itxt
-                        PRIVATE ZLIB::ZLIB ${M_LIBRARY})
+                        PRIVATE ${PNG_LINK_LIBRARIES})
   list(APPEND PNG_BIN_TARGETS png-fix-itxt)
 endif()
 

Makefile.in

@@ -1,4 +1,4 @@
-# Makefile.in generated by automake 1.18 from Makefile.am.
+# Makefile.in generated by automake 1.18.1 from Makefile.am.
 # @configure_input@
 
 # Copyright (C) 1994-2025 Free Software Foundation, Inc.

README

@@ -1,5 +1,5 @@
-README for libpng version 1.6.49
-================================
+README for libpng version 1.6.51.git
+====================================
 
 See the note about version numbers near the top of `png.h`.
 See `INSTALL` for instructions on how to install libpng.

aclocal.m4

@@ -1,4 +1,4 @@
-# generated automatically by aclocal 1.18 -*- Autoconf -*-
+# generated automatically by aclocal 1.18.1 -*- Autoconf -*-
 
 # Copyright (C) 1996-2025 Free Software Foundation, Inc.
 
@@ -35,7 +35,7 @@ AC_DEFUN([AM_AUTOMAKE_VERSION],
 [am__api_version='1.18'
 dnl Some users find AM_AUTOMAKE_VERSION and mistake it for a way to
 dnl require some minimum version.  Point them to the right macro.
-m4_if([$1], [1.18], [],
+m4_if([$1], [1.18.1], [],
       [AC_FATAL([Do not call $0, use AM_INIT_AUTOMAKE([$1]).])])dnl
 ])
 
@@ -51,7 +51,7 @@ m4_define([_AM_AUTOCONF_VERSION], [])
 # Call AM_AUTOMAKE_VERSION and AM_AUTOMAKE_VERSION so they can be traced.
 # This function is AC_REQUIREd by AM_INIT_AUTOMAKE.
 AC_DEFUN([AM_SET_CURRENT_AUTOMAKE_VERSION],
-[AM_AUTOMAKE_VERSION([1.18])dnl
+[AM_AUTOMAKE_VERSION([1.18.1])dnl
 m4_ifndef([AC_AUTOCONF_VERSION],
   [m4_copy([m4_PACKAGE_VERSION], [AC_AUTOCONF_VERSION])])dnl
 _AM_AUTOCONF_VERSION(m4_defn([AC_AUTOCONF_VERSION]))])

compile

@@ -1,7 +1,7 @@
 #! /bin/sh
 # Wrapper for compilers which do not understand '-c -o'.
 
-scriptversion=2025-02-03.05; # UTC
+scriptversion=2025-06-18.21; # UTC
 
 # Copyright (C) 1999-2025 Free Software Foundation, Inc.
 # Written by Tom Tromey <tromey@cygnus.com>.
@@ -358,7 +358,7 @@ exit $ret
 # sh-indentation: 2
 # eval: (add-hook 'before-save-hook 'time-stamp nil t)
 # time-stamp-start: "scriptversion="
-# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-format: "%Y-%02m-%02d.%02H"
 # time-stamp-time-zone: "UTC0"
 # time-stamp-end: "; # UTC"
 # End:

config.h.in

@@ -108,12 +108,6 @@
 /* Enable POWERPC VSX optimizations */
 #undef PNG_POWERPC_VSX_OPT
 
-/* Turn on RISC-V Vector optimizations at run-time */
-#undef PNG_RISCV_RVV_API_SUPPORTED
-
-/* Check for RISC-V Vector support at run-time */
-#undef PNG_RISCV_RVV_CHECK_SUPPORTED
-
 /* Enable RISCV RVV optimizations */
 #undef PNG_RISCV_RVV_OPT
 

configure

@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.72 for libpng 1.6.49.
+# Generated by GNU Autoconf 2.72 for libpng 1.6.51.git.
 #
 # Report bugs to <png-mng-implement@lists.sourceforge.net>.
 #
@@ -614,8 +614,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='libpng'
 PACKAGE_TARNAME='libpng'
-PACKAGE_VERSION='1.6.49'
-PACKAGE_STRING='libpng 1.6.49'
+PACKAGE_VERSION='1.6.51.git'
+PACKAGE_STRING='libpng 1.6.51.git'
 PACKAGE_BUGREPORT='png-mng-implement@lists.sourceforge.net'
 PACKAGE_URL=''
 
@@ -1424,7 +1424,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-'configure' configures libpng 1.6.49 to adapt to many kinds of systems.
+'configure' configures libpng 1.6.51.git to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1495,7 +1495,7 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of libpng 1.6.49:";;
+     short | recursive ) echo "Configuration of libpng 1.6.51.git:";;
    esac
   cat <<\_ACEOF
 
@@ -1597,8 +1597,8 @@ Optional Features:
                           api, yes/on: no/off: disable the optimizations;
                           check: use internal checking code api: disable by
                           default, enable by a call to png_set_option yes/on:
-                          turn on unconditionally. If not specified:
-                          determined by the compiler.
+                          turn on. If not specified: determined by the
+                          compiler.
 
 Optional Packages:
   --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
@@ -1698,7 +1698,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-libpng configure 1.6.49
+libpng configure 1.6.51.git
 generated by GNU Autoconf 2.72
 
 Copyright (C) 2023 Free Software Foundation, Inc.
@@ -1961,7 +1961,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by libpng $as_me 1.6.49, which was
+It was created by libpng $as_me 1.6.51.git, which was
 generated by GNU Autoconf 2.72.  Invocation command line was
 
   $ $0$ac_configure_args_raw
@@ -3446,7 +3446,7 @@ fi
 
 # Define the identity of the package.
  PACKAGE='libpng'
- VERSION='1.6.49'
+ VERSION='1.6.51.git'
 
 
 printf "%s\n" "#define PACKAGE \"$PACKAGE\"" >>confdefs.h
@@ -3665,10 +3665,10 @@ fi
 
 
 
-PNGLIB_VERSION=1.6.49
+PNGLIB_VERSION=1.6.51.git
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=6
-PNGLIB_RELEASE=49
+PNGLIB_RELEASE=51
 
 
 
@@ -15716,28 +15716,14 @@ printf "%s\n" "#define PNG_RISCV_RVV_OPT 0" >>confdefs.h
 
          # Prevent inclusion of the platform-specific files below:
          enable_riscv_rvv=no ;;
-      check)
-
-printf "%s\n" "#define PNG_RISCV_RVV_CHECK_SUPPORTED /**/" >>confdefs.h
-
-         { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: --enable-riscv-rvv Please check contrib/riscv-rvv/README file
-            for the list of supported OSes." >&5
-printf "%s\n" "$as_me: WARNING: --enable-riscv-rvv Please check contrib/riscv-rvv/README file
-            for the list of supported OSes." >&2;};;
-      api)
-
-printf "%s\n" "#define PNG_RISCV_RVV_API_SUPPORTED /**/" >>confdefs.h
-;;
       yes|on)
 
 printf "%s\n" "#define PNG_RISCV_RVV_OPT 2" >>confdefs.h
 
-         { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: --enable-riscv-rvv: please specify 'check' or 'api', if
-            you want the optimizations unconditionally pass e.g. '-march=rv64gv'
-            to the compiler." >&5
-printf "%s\n" "$as_me: WARNING: --enable-riscv-rvv: please specify 'check' or 'api', if
-            you want the optimizations unconditionally pass e.g. '-march=rv64gv'
-            to the compiler." >&2;};;
+         { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: --enable-riscv-rvv:
+            if you want the optimizations pass e.g. '-march=rv64gv1p0' to the compiler." >&5
+printf "%s\n" "$as_me: WARNING: --enable-riscv-rvv:
+            if you want the optimizations pass e.g. '-march=rv64gv1p0' to the compiler." >&2;};;
       *)
          as_fn_error $? "--enable-riscv-rvv=${enable_riscv_rvv}: invalid value" "$LINENO" 5
    esac
@@ -15754,14 +15740,20 @@ then
    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether to use RISC-V RVV intrinsics" >&5
 printf %s "checking whether to use RISC-V RVV intrinsics... " >&6; }
 
-   save_CFLAGS=$CFLAGS
-   CFLAGS="$CFLAGS -march=rv64gv"
    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
 #include <riscv_vector.h>
+#include <asm/hwcap.h>
+#ifndef COMPAT_HWCAP_ISA_V /* added in linux-6.5 */
+#error "COMPAT_HWCAP_ISA_V is not available"
+#endif
 int main() {
-   return 0;
+   const float src[] = { 0.0f, 0.0f, 0.0f, 0.0f };
+   uint64_t ptr[2] = {0x0908060504020100, 0xFFFFFFFF0E0D0C0A};
+   vuint8m1_t a = __riscv_vreinterpret_v_u64m1_u8m1(__riscv_vle64_v_u64m1(ptr, 2));
+   vfloat32m1_t val = __riscv_vle32_v_f32m1((const float*)(src), 4);
+   return (int)__riscv_vfmv_f_s_f32m1_f32(val);
 }
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"
@@ -15779,7 +15771,6 @@ printf "%s\n" "#define PNG_RISCV_RVV_OPT 1" >>confdefs.h
       { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: Compiler does not support riscv rvv." >&5
 printf "%s\n" "$as_me: WARNING: Compiler does not support riscv rvv." >&2;}
    fi
-   CFLAGS=$save_CFLAGS
 fi
 
 # Add RISC-V-specific files to all builds where $host_cpu is riscv ('riscv64')
@@ -16419,7 +16410,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by libpng $as_me 1.6.49, which was
+This file was extended by libpng $as_me 1.6.51.git, which was
 generated by GNU Autoconf 2.72.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -16487,7 +16478,7 @@ ac_cs_config_escaped=`printf "%s\n" "$ac_cs_config" | sed "s/^ //; s/'/'\\\\\\\\
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config='$ac_cs_config_escaped'
 ac_cs_version="\\
-libpng config.status 1.6.49
+libpng config.status 1.6.51.git
 configured by $0, generated by GNU Autoconf 2.72,
   with options \\"\$ac_cs_config\\"
 

configure.ac

@@ -25,7 +25,7 @@ AC_PREREQ([2.68])
 
 dnl Version number stuff here:
 
-AC_INIT([libpng],[1.6.49],[png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng],[1.6.51.git],[png-mng-implement@lists.sourceforge.net])
 AC_CONFIG_MACRO_DIR([scripts/autoconf])
 
 # libpng does not follow GNU file name conventions (hence 'foreign')
@@ -46,10 +46,10 @@ dnl automake, so the following is not necessary (and is not defined anyway):
 dnl AM_PREREQ([1.11.2])
 dnl stop configure from automagically running automake
 
-PNGLIB_VERSION=1.6.49
+PNGLIB_VERSION=1.6.51.git
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=6
-PNGLIB_RELEASE=49
+PNGLIB_RELEASE=51
 
 dnl End of version number stuff
 
@@ -679,8 +679,7 @@ AS_HELP_STRING([[[--enable-riscv-rvv]]],
       [Enable RISC-V Vector optimizations: =no/off, check, api, yes/on:]
       [no/off: disable the optimizations; check: use internal checking code]
       [api: disable by default, enable by a call to png_set_option]
-      [yes/on: turn on unconditionally.]
-      [If not specified: determined by the compiler.]),
+      [yes/on: turn on. If not specified: determined by the compiler.]),
    [case "$enableval" in
       no|off)
          # disable the default enabling on __riscv systems:
@@ -688,20 +687,11 @@ AS_HELP_STRING([[[--enable-riscv-rvv]]],
                    [Disable RISC-V Vector optimizations])
          # Prevent inclusion of the platform-specific files below:
          enable_riscv_rvv=no ;;
-      check)
-         AC_DEFINE([PNG_RISCV_RVV_CHECK_SUPPORTED], [],
-                   [Check for RISC-V Vector support at run-time])
-         AC_MSG_WARN([--enable-riscv-rvv Please check contrib/riscv-rvv/README file]
-            [for the list of supported OSes.]);;
-      api)
-         AC_DEFINE([PNG_RISCV_RVV_API_SUPPORTED], [],
-                   [Turn on RISC-V Vector optimizations at run-time]);;
       yes|on)
          AC_DEFINE([PNG_RISCV_RVV_OPT], [2],
                    [Enable RISC-V Vector optimizations])
-         AC_MSG_WARN([--enable-riscv-rvv: please specify 'check' or 'api', if]
-            [you want the optimizations unconditionally pass e.g. '-march=rv64gv']
-            [to the compiler.]);;
+         AC_MSG_WARN([--enable-riscv-rvv:]
+            [if you want the optimizations pass e.g. '-march=rv64gv1p0' to the compiler.]);;
       *)
          AC_MSG_ERROR([--enable-riscv-rvv=${enable_riscv_rvv}: invalid value])
    esac])
@@ -715,12 +705,18 @@ then
    compiler_support_riscv_rvv=no
    AC_MSG_CHECKING(whether to use RISC-V RVV intrinsics)
 
-   save_CFLAGS=$CFLAGS
-   CFLAGS="$CFLAGS -march=rv64gv"
    AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
 #include <riscv_vector.h>
+#include <asm/hwcap.h>
+#ifndef COMPAT_HWCAP_ISA_V /* added in linux-6.5 */
+#error "COMPAT_HWCAP_ISA_V is not available"
+#endif
 int main() {
-   return 0;
+   const float src[] = { 0.0f, 0.0f, 0.0f, 0.0f };
+   uint64_t ptr[2] = {0x0908060504020100, 0xFFFFFFFF0E0D0C0A};
+   vuint8m1_t a = __riscv_vreinterpret_v_u64m1_u8m1(__riscv_vle64_v_u64m1(ptr, 2));
+   vfloat32m1_t val = __riscv_vle32_v_f32m1((const float*)(src), 4);
+   return (int)__riscv_vfmv_f_s_f32m1_f32(val);
 }]])],compiler_support_riscv_rvv=yes)
    AC_MSG_RESULT($compiler_support_riscv_rvv)
    if test "$compiler_support_riscv_rvv" = "yes"; then
@@ -729,7 +725,6 @@ int main(){
    else
       AC_MSG_WARN([Compiler does not support riscv rvv.])
    fi
-   CFLAGS=$save_CFLAGS
 fi
 
 # Add RISC-V-specific files to all builds where $host_cpu is riscv ('riscv64')

contrib/riscv-rvv/linux.c

@@ -25,7 +25,7 @@
 #endif
 
 static int
-png_have_rvv(png_structp png_ptr) {
+png_have_rvv() {
 #if defined(__linux__)
    return getauxval (AT_HWCAP) & COMPAT_HWCAP_ISA_V ? 1 : 0;
 #else

depcomp

@@ -1,7 +1,7 @@
 #! /bin/sh
 # depcomp - compile a program generating dependencies as side-effects
 
-scriptversion=2024-12-03.03; # UTC
+scriptversion=2025-06-18.21; # UTC
 
 # Copyright (C) 1999-2025 Free Software Foundation, Inc.
 
@@ -786,7 +786,7 @@ exit 0
 # sh-indentation: 2
 # eval: (add-hook 'before-save-hook 'time-stamp nil t)
 # time-stamp-start: "scriptversion="
-# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-format: "%Y-%02m-%02d.%02H"
 # time-stamp-time-zone: "UTC0"
 # time-stamp-end: "; # UTC"
 # End:

install-sh

@@ -1,7 +1,7 @@
 #!/bin/sh
 # install - install a program, script, or datafile
 
-scriptversion=2024-12-03.03; # UTC
+scriptversion=2025-06-18.21; # UTC
 
 # This originates from X11R5 (mit/util/scripts/install.sh), which was
 # later released in X11R6 (xc/config/util/install.sh) with the
@@ -535,7 +535,7 @@ done
 # Local variables:
 # eval: (add-hook 'before-save-hook 'time-stamp nil t)
 # time-stamp-start: "scriptversion="
-# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-format: "%Y-%02m-%02d.%02H"
 # time-stamp-time-zone: "UTC0"
 # time-stamp-end: "; # UTC"
 # End:

libpng-manual.txt

@@ -9,7 +9,7 @@ libpng-manual.txt - A description on how to use and modify libpng
 
  Based on:
 
- libpng version 1.6.36, December 2018, through 1.6.49 - June 2025
+ libpng version 1.6.36, December 2018, through 1.6.50 - July 2025
  Updated and distributed by Cosmin Truta
  Copyright (c) 2018-2025 Cosmin Truta
 
@@ -65,18 +65,22 @@ Libpng was written as a companion to the PNG specification, as a way
 of reducing the amount of time and effort it takes to support the PNG
 file format in application programs.
 
-The PNG specification (second edition), November 2003, is available as
+The PNG specification (Third Edition), June 2025, is available as
+a W3C Recommendation at
+<https://www.w3.org/TR/2025/REC-png-3-20250624/>.
+
+The PNG specification (Second Edition), November 2003, is available as
 a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2004 (E)) at
 <https://www.w3.org/TR/2003/REC-PNG-20031110/>.
 The W3C and ISO documents have identical technical content.
 
 The PNG-1.2 specification is available at
-<https://png-mng.sourceforge.io/pub/png/spec/1.2/>.
-It is technically equivalent
-to the PNG specification (second edition) but has some additional material.
+<https://www.libpng.org/pub/png/spec/1.2/>.
+It is technically equivalent to the PNG specification (Second Edition)
+but has some additional material.
 
 The PNG-1.0 specification is available as RFC 2083 at
-<https://png-mng.sourceforge.io/pub/png/spec/1.0/> and as a
+<https://www.libpng.org/pub/png/spec/1.0/> and as a
 W3C Recommendation at <https://www.w3.org/TR/REC-png-961001>.
 
 Some additional chunks are described in the special-purpose public chunks

libpng.3

@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "June 12, 2025"
+.TH LIBPNG 3 "July 1, 2025"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.49
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.50
 
 .SH SYNOPSIS
 \fB#include <png.h>\fP
@@ -528,7 +528,7 @@ libpng-manual.txt - A description on how to use and modify libpng
 
  Based on:
 
- libpng version 1.6.36, December 2018, through 1.6.49 - June 2025
+ libpng version 1.6.36, December 2018, through 1.6.50 - July 2025
  Updated and distributed by Cosmin Truta
  Copyright (c) 2018-2025 Cosmin Truta
 
@@ -584,18 +584,22 @@ Libpng was written as a companion to the PNG specification, as a way
 of reducing the amount of time and effort it takes to support the PNG
 file format in application programs.
 
-The PNG specification (second edition), November 2003, is available as
+The PNG specification (Third Edition), June 2025, is available as
+a W3C Recommendation at
+<https://www.w3.org/TR/2025/REC-png-3-20250624/>.
+
+The PNG specification (Second Edition), November 2003, is available as
 a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2004 (E)) at
 <https://www.w3.org/TR/2003/REC-PNG-20031110/>.
 The W3C and ISO documents have identical technical content.
 
 The PNG-1.2 specification is available at
-<https://png-mng.sourceforge.io/pub/png/spec/1.2/>.
-It is technically equivalent
-to the PNG specification (second edition) but has some additional material.
+<https://www.libpng.org/pub/png/spec/1.2/>.
+It is technically equivalent to the PNG specification (Second Edition)
+but has some additional material.
 
 The PNG-1.0 specification is available as RFC 2083 at
-<https://png-mng.sourceforge.io/pub/png/spec/1.0/> and as a
+<https://www.libpng.org/pub/png/spec/1.0/> and as a
 W3C Recommendation at <https://www.w3.org/TR/REC-png-961001>.
 
 Some additional chunks are described in the special-purpose public chunks

libpngpf.3

@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "June 12, 2025"
+.TH LIBPNGPF 3 "July 1, 2025"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.49
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.50
 
 .SH SYNOPSIS
 \fB#include "pngpriv.h"\fP

missing

@@ -1,7 +1,7 @@
 #! /bin/sh
 # Common wrapper for a few potentially missing GNU and other programs.
 
-scriptversion=2024-12-03.03; # UTC
+scriptversion=2025-06-18.21; # UTC
 
 # shellcheck disable=SC2006,SC2268 # we must support pre-POSIX shells
 
@@ -230,7 +230,7 @@ exit $st
 # Local variables:
 # eval: (add-hook 'before-save-hook 'time-stamp nil t)
 # time-stamp-start: "scriptversion="
-# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-format: "%Y-%02m-%02d.%02H"
 # time-stamp-time-zone: "UTC0"
 # time-stamp-end: "; # UTC"
 # End:

png.5

@@ -1,4 +1,4 @@
-.TH PNG 5 "June 12, 2025"
+.TH PNG 5 "July 1, 2025"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 
@@ -20,20 +20,25 @@ matching on heterogeneous platforms.
 .SH "SEE ALSO"
 .BR "libpng"(3), " zlib"(3), " deflate"(5), " " and " zlib"(5)
 .LP
-PNG Specification (Third Edition) Proposed Recommendation, May 2025:
+PNG Specification (Third Edition), June 2025:
 .IP
 .br
-https://www.w3.org/TR/2025/PR-png-3-20250515/
+https://www.w3.org/TR/2025/REC-png-3-20250624/
 .LP
 PNG Specification (Second Edition), November 2003:
 .IP
 .br
 https://www.w3.org/TR/2003/REC-PNG-20031110/
 .LP
-PNG 1.2 Specification, July 1999:
+PNG 1.2 Specification, August 1999:
 .IP
 .br
-https://png-mng.sourceforge.io/pub/png/spec/1.2/
+https://www.libpng.org/pub/png/spec/1.2/
+.LP
+PNG 1.1 Specification, December 1998:
+.IP
+.br
+https://www.libpng.org/pub/png/spec/1.1/
 .LP
 PNG 1.0 Specification, October 1996:
 .IP
@@ -50,15 +55,24 @@ https://www.w3.org/TR/REC-png-961001
 .SH AUTHORS
 This man page: Glenn Randers-Pehrson, Cosmin Truta
 .LP
+Portable Network Graphics (PNG) Specification (Third Edition).
+W3C Recommendation 24 June 2025:
+Chris Blume et al.
+.LP
 Portable Network Graphics (PNG) Specification (Second Edition)
 Information technology - Computer graphics and image processing -
 Portable Network Graphics (PNG): Functional specification.
-ISO/IEC 15948:2003 (E) (November 10, 2003): David Duce and others.
+ISO/IEC 15948:2003 (E), W3C Recommendation 10 November 2003:
+David Duce et al.
 .LP
-Portable Network Graphics (PNG) Specification Version 1.2 (July 8, 1999):
-Glenn Randers-Pehrson and others.
+Portable Network Graphics (PNG) Specification Version 1.2 (11 August 1999):
+Glenn Randers-Pehrson et al.
 .LP
-Portable Network Graphics (PNG) Specification Version 1.0 (October 1, 1996):
-Thomas Boutell and others.
+Portable Network Graphics (PNG) Specification Version 1.1 (31 December 1998):
+Glenn Randers-Pehrson et al.
+.LP
+Portable Network Graphics (PNG) Specification Version 1.0.
+IETF RFC 2083, W3C Recommendation 1 October 1996:
+Thomas Boutell et al.
 
 .\" end of man page

png.c

@@ -13,7 +13,7 @@
 #include "pngpriv.h"
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_6_49 Your_png_h_is_not_version_1_6_49;
+typedef png_libpng_version_1_6_51_git Your_png_h_is_not_version_1_6_51_git;
 
 /* Sanity check the chunks definitions - PNG_KNOWN_CHUNKS from pngpriv.h and the
  * corresponding macro definitions.  This causes a compile time failure if
@@ -108,7 +108,13 @@ png_zalloc,(voidpf png_ptr, uInt items, uInt size),PNG_ALLOCATED)
    if (png_ptr == NULL)
       return NULL;
 
-   if (items >= (~(png_alloc_size_t)0)/size)
+   /* This check against overflow is vestigial, dating back from
+    * the old times when png_zalloc used to be an exported function.
+    * We're still keeping it here for now, as an extra-cautious
+    * prevention against programming errors inside zlib, although it
+    * should rather be a debug-time assertion instead.
+    */
+   if (size != 0 && items >= (~(png_alloc_size_t)0) / size)
    {
       png_warning(png_voidcast(png_structrp, png_ptr),
                   "Potential overflow in png_zalloc()");
@@ -815,7 +821,7 @@ png_get_copyright(png_const_structrp png_ptr)
    return PNG_STRING_COPYRIGHT
 #else
    return PNG_STRING_NEWLINE \
-      "libpng version 1.6.49" PNG_STRING_NEWLINE \
+      "libpng version 1.6.51.git" PNG_STRING_NEWLINE \
       "Copyright (c) 2018-2025 Cosmin Truta" PNG_STRING_NEWLINE \
       "Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson" \
       PNG_STRING_NEWLINE \

png.h

@@ -1,6 +1,6 @@
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.6.49
+ * libpng version 1.6.51.git
  *
  * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
@@ -14,7 +14,7 @@
  *   libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger
  *   libpng versions 0.97, January 1998, through 1.6.35, July 2018:
  *     Glenn Randers-Pehrson
- *   libpng versions 1.6.36, December 2018, through 1.6.49, June 2025:
+ *   libpng versions 1.6.36, December 2018, through 1.6.50, July 2025:
  *     Cosmin Truta
  *   See also "Contributing Authors", below.
  */
@@ -238,7 +238,7 @@
  *    ...
  *    1.5.30                  15    10530  15.so.15.30[.0]
  *    ...
- *    1.6.49                  16    10649  16.so.16.49[.0]
+ *    1.6.50                  16    10650  16.so.16.50[.0]
  *
  *    Henceforth the source version will match the shared-library major and
  *    minor numbers; the shared-library major version number will be used for
@@ -274,7 +274,7 @@
  */
 
 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.6.49"
+#define PNG_LIBPNG_VER_STRING "1.6.51.git"
 #define PNG_HEADER_VERSION_STRING " libpng version " PNG_LIBPNG_VER_STRING "\n"
 
 /* The versions of shared library builds should stay in sync, going forward */
@@ -285,12 +285,12 @@
 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
 #define PNG_LIBPNG_VER_MAJOR   1
 #define PNG_LIBPNG_VER_MINOR   6
-#define PNG_LIBPNG_VER_RELEASE 49
+#define PNG_LIBPNG_VER_RELEASE 51
 
 /* This should be zero for a public release, or non-zero for a
  * development version.
  */
-#define PNG_LIBPNG_VER_BUILD 0
+#define PNG_LIBPNG_VER_BUILD 1
 
 /* Release Status */
 #define PNG_LIBPNG_BUILD_ALPHA               1
@@ -307,7 +307,7 @@
 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
                                        PNG_LIBPNG_BUILD_PRIVATE */
 
-#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
+#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_BETA
 
 /* Careful here.  At one time, Guy wanted to use 082, but that
  * would be octal.  We must not include leading zeros.
@@ -316,7 +316,7 @@
  * From version 1.0.1 it is:
  * XXYYZZ, where XX=major, YY=minor, ZZ=release
  */
-#define PNG_LIBPNG_VER 10649 /* 1.6.49 */
+#define PNG_LIBPNG_VER 10651 /* 1.6.51.git */
 
 /* Library configuration: these options cannot be changed after
  * the library has been built.
@@ -426,7 +426,7 @@ extern "C" {
 /* This triggers a compiler error in png.c, if png.c and png.h
  * do not agree upon the version number.
  */
-typedef char* png_libpng_version_1_6_49;
+typedef char* png_libpng_version_1_6_51_git;
 
 /* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
  *

pngconf.h

@@ -1,6 +1,6 @@
 /* pngconf.h - machine-configurable file for libpng
  *
- * libpng version 1.6.49
+ * libpng version 1.6.51.git
  *
  * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson

pngpread.c

@@ -229,6 +229,14 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
          png_benign_error(png_ptr, "Too many IDATs found");
    }
 
+   else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+   {
+      /* These flags must be set consistently for all non-IDAT chunks,
+       * including the unknown chunks.
+       */
+      png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT | PNG_AFTER_IDAT;
+   }
+
    if (chunk_name == png_IHDR)
    {
       if (png_ptr->push_length != 13)

pngpriv.h

@@ -154,12 +154,8 @@
     * to configure or put -DPNG_RISCV_RVV_OPT=2 in CPPFLAGS.
     */
 
-#  if defined(__riscv) && defined(PNG_ALIGNED_MEMORY_SUPPORTED)
-#     define PNG_RISCV_RVV_OPT 1
-#  else
 #  define PNG_RISCV_RVV_OPT 0
 #endif
-#endif
 
 #if PNG_ARM_NEON_OPT > 0
    /* NEON optimizations are to be at least considered by libpng, so enable the

pngread.c

@@ -702,7 +702,12 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
       png_uint_32 chunk_name = png_ptr->chunk_name;
 
       if (chunk_name != png_IDAT)
-         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
+      {
+         /* These flags must be set consistently for all non-IDAT chunks,
+          * including the unknown chunks.
+          */
+         png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT | PNG_AFTER_IDAT;
+      }
 
       if (chunk_name == png_IEND)
          png_handle_chunk(png_ptr, info_ptr, length);

pngrutil.c

@@ -2412,10 +2412,6 @@ png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
    }
 #endif
 
-   /* TODO: this doesn't work and shouldn't be necessary. */
-   if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
-      png_ptr->mode |= PNG_AFTER_IDAT;
-
    buffer = png_read_buffer(png_ptr, length+1);
 
    if (buffer == NULL)
@@ -2486,10 +2482,6 @@ png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
    }
 #endif
 
-   /* TODO: should not be necessary. */
-   if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
-      png_ptr->mode |= PNG_AFTER_IDAT;
-
    /* Note, "length" is sufficient here; we won't be adding
     * a null terminator later.  The limit check in png_handle_chunk should be
     * sufficient.
@@ -2606,10 +2598,6 @@ png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
    }
 #endif
 
-   /* TODO: should not be necessary. */
-   if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
-      png_ptr->mode |= PNG_AFTER_IDAT;
-
    buffer = png_read_buffer(png_ptr, length+1);
 
    if (buffer == NULL)

pngtest.c

@@ -50,7 +50,7 @@
 #define STDERR stdout
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_6_49 Your_png_h_is_not_version_1_6_49;
+typedef png_libpng_version_1_6_51_git Your_png_h_is_not_version_1_6_51_git;
 
 /* Ensure that all version numbers in png.h are consistent with one another. */
 #if (PNG_LIBPNG_VER != PNG_LIBPNG_VER_MAJOR * 10000 + \

riscv/filter_rvv_intrinsics.c

@@ -51,21 +51,22 @@ png_read_filter_row_sub_rvv(size_t len, size_t bpp, unsigned char* row)
     * x .. [v8](e8)
     */
 
-   asm volatile ("vsetvli      zero, %0, e8, m1" : : "r" (bpp));
+   size_t vl = __riscv_vsetvl_e8m1(bpp);
 
    /* a = *row */
-   asm volatile ("vle8.v       v0, (%0)" : : "r" (row));
+   vuint8m1_t a = __riscv_vle8_v_u8m1(row, vl);
    row += bpp;
 
    while (row < rp_end)
    {
       /* x = *row */
-      asm volatile ("vle8.v       v8, (%0)" : : "r" (row));
+      vuint8m1_t x = __riscv_vle8_v_u8m1(row, vl);
+
       /* a = a + x */
-      asm volatile ("vadd.vv      v0, v0, v8");
+      a = __riscv_vadd_vv_u8m1(a, x, vl);
 
       /* *row = a */
-      asm volatile ("vse8.v       v0, (%0)" : : "r" (row));
+      __riscv_vse8_v_u8m1(row, a, vl);
       row += bpp;
    }
 }
@@ -110,44 +111,46 @@ png_read_filter_row_avg_rvv(size_t len, size_t bpp, unsigned char* row,
 
    /* first pixel */
 
-   asm volatile ("vsetvli      zero, %0, e8, m1" : : "r" (bpp));
+   size_t vl = __riscv_vsetvl_e8m1(bpp);
 
    /* b = *prev_row */
-   asm volatile ("vle8.v       v4, (%0)" : : "r" (prev_row));
+   vuint8m1_t b = __riscv_vle8_v_u8m1(prev_row, vl);
    prev_row += bpp;
 
    /* x = *row */
-   asm volatile ("vle8.v       v8, (%0)" : : "r" (row));
+   vuint8m1_t x = __riscv_vle8_v_u8m1(row, vl);
 
    /* b = b / 2 */
-   asm volatile ("vsrl.vi      v4, v4, 1");
+   b = __riscv_vsrl_vx_u8m1(b, 1, vl);
+
    /* a = x + b */
-   asm volatile ("vadd.vv      v2, v4, v8");
+   vuint8m1_t a = __riscv_vadd_vv_u8m1(b, x, vl);
 
    /* *row = a */
-   asm volatile ("vse8.v       v2, (%0)" : : "r" (row));
+   __riscv_vse8_v_u8m1(row, a, vl);
    row += bpp;
 
    /* remaining pixels */
-
    while (row < rp_end)
    {
       /* b = *prev_row */
-      asm volatile ("vle8.v       v4, (%0)" : : "r" (prev_row));
+      b = __riscv_vle8_v_u8m1(prev_row, vl);
       prev_row += bpp;
 
       /* x = *row */
-      asm volatile ("vle8.v       v8, (%0)" : : "r" (row));
+      x = __riscv_vle8_v_u8m1(row, vl);
 
       /* tmp = a + b */
-      asm volatile ("vwaddu.vv    v12, v2, v4"); /* add with widening */
+      vuint16m2_t tmp = __riscv_vwaddu_vv_u16m2(a, b, vl);
+
       /* a = tmp/2 */
-      asm volatile ("vnsrl.wi     v2, v12, 1");  /* divide/shift with narrowing */
+      a = __riscv_vnsrl_wx_u8m1(tmp, 1, vl);
+
       /* a += x */
-      asm volatile ("vadd.vv      v2, v2, v8");
+      a = __riscv_vadd_vv_u8m1(a, x, vl);
 
       /* *row = a */
-      asm volatile ("vse8.v       v2, (%0)" : : "r" (row));
+      __riscv_vse8_v_u8m1(row, a, vl);
       row += bpp;
    }
 }
@@ -205,18 +208,14 @@ static inline vint16m1_t
 abs_diff(vuint16m1_t a, vuint16m1_t b, size_t vl)
 {
    vint16m1_t diff = __riscv_vreinterpret_v_u16m1_i16m1(__riscv_vsub_vv_u16m1(a, b, vl));
-   vint16m1_t neg = __riscv_vneg_v_i16m1(diff, vl);
-
-   return __riscv_vmax_vv_i16m1(diff, neg, vl);
+   vbool16_t mask = __riscv_vmslt_vx_i16m1_b16(diff, 0, vl);
+   return __riscv_vrsub_vx_i16m1_m(mask, diff, 0, vl);
 }
 
 static inline vint16m1_t
 abs_sum(vint16m1_t a, vint16m1_t b, size_t vl)
 {
-   vint16m1_t sum = __riscv_vadd_vv_i16m1(a, b, vl);
-   vint16m1_t neg = __riscv_vneg_v_i16m1(sum, vl);
-
-   return __riscv_vmax_vv_i16m1(sum, neg, vl);
+   return __riscv_vadd_vv_i16m1(a, b, vl);
 }
 
 static inline void
@@ -229,119 +228,106 @@ png_read_filter_row_paeth_rvv(size_t len, size_t bpp, unsigned char* row,
     * row:  | a | x |
     * prev: | c | b |
     *
-    * mask ..   [v0]
     * a .. [v2](e8)
     * b .. [v4](e8)
     * c .. [v6](e8)
     * x .. [v8](e8)
     * p .. [v12-v13](e16)
-    * pa ..     [v16-v17](e16)
-    * pb ..     [v20-v21](e16)
-    * pc ..     [v24-v25](e16)
-    * tmpmask ..[v31]
+    * pa, pb, pc .. [v16-v17, v20-v21, v24-v25](e16)
     */
 
    /* first pixel */
 
-   asm volatile ("vsetvli      zero, %0, e8, m1" : : "r" (bpp));
+   size_t vl = __riscv_vsetvl_e8m1(bpp);
 
-   /* a = *row + *prev_row */
-   asm volatile ("vle8.v       v2, (%0)" : : "r" (row));
-   asm volatile ("vle8.v       v6, (%0)" : : "r" (prev));
-   prev += bpp;
-   asm volatile ("vadd.vv      v2, v2, v6");
+   /* a = *row */
+   vuint8m1_t a = __riscv_vle8_v_u8m1(row, vl);
+
+   /* c = *prev */
+   vuint8m1_t c = __riscv_vle8_v_u8m1(prev, vl);
+
+   /* a += c */
+   a = __riscv_vadd_vv_u8m1(a, c, vl);
 
    /* *row = a */
-   asm volatile ("vse8.v       v2, (%0)" : : "r" (row));
+   __riscv_vse8_v_u8m1(row, a, vl);
    row += bpp;
+   prev += bpp;
 
    /* remaining pixels */
+
    while (row < rp_end)
    {
-      /* b = *prev_row */
-      asm volatile ("vle8.v       v4, (%0)" : : "r" (prev));
+      /* b = *prev */
+      vuint8m1_t b = __riscv_vle8_v_u8m1(prev, vl);
       prev += bpp;
 
       /* x = *row */
-      asm volatile ("vle8.v       v8, (%0)" : : "r" (row));
+      vuint8m1_t x = __riscv_vle8_v_u8m1(row, vl);
 
-      /* sub (widening to 16bit) */
-      /* p = b - c */
-      asm volatile ("vwsubu.vv    v12, v4, v6");
-      /* pc = a - c */
-      asm volatile ("vwsubu.vv    v24, v2, v6");
+      /* Calculate p = b - c and pc = a - c using widening subtraction */
+      vuint16m2_t p_wide = __riscv_vwsubu_vv_u16m2(b, c, vl);
+      vuint16m2_t pc_wide = __riscv_vwsubu_vv_u16m2(a, c, vl);
 
-      /* switch to widened */
-      asm volatile ("vsetvli      zero, %0, e16, m2" : : "r" (bpp));
+      /* Convert to signed for easier manipulation */
+      size_t vl16 = __riscv_vsetvl_e16m2(bpp);
+      vint16m2_t p = __riscv_vreinterpret_v_u16m2_i16m2(p_wide);
+      vint16m2_t pc = __riscv_vreinterpret_v_u16m2_i16m2(pc_wide);
 
-      /* pa = abs(p) -> pa = p < 0 ? -p : p */
-      asm volatile ("vmv.v.v      v16, v12");             /* pa = p */
-      asm volatile ("vmslt.vx     v0, v16, zero");        /* set mask[i] if pa[i] < 0 */
-      asm volatile ("vrsub.vx     v16, v16, zero, v0.t"); /* invert negative values in pa; vd[i] = 0 - vs2[i] (if mask[i])
-                                                           * could be replaced by vneg in rvv >= 1.0
-                                                           */
+      /* pa = |p| */
+      vbool8_t p_neg_mask = __riscv_vmslt_vx_i16m2_b8(p, 0, vl16);
+      vint16m2_t pa = __riscv_vrsub_vx_i16m2_m(p_neg_mask, p, 0, vl16);
 
-      /* pb = abs(p) -> pb = pc < 0 ? -pc : pc */
-      asm volatile ("vmv.v.v      v20, v24");             /* pb = pc */
-      asm volatile ("vmslt.vx     v0, v20, zero");        /* set mask[i] if pc[i] < 0 */
-      asm volatile ("vrsub.vx     v20, v20, zero, v0.t"); /* invert negative values in pb; vd[i] = 0 - vs2[i] (if mask[i])
-                                                           * could be replaced by vneg in rvv >= 1.0
-                                                           */
+      /* pb = |pc| */
+      vbool8_t pc_neg_mask = __riscv_vmslt_vx_i16m2_b8(pc, 0, vl16);
+      vint16m2_t pb = __riscv_vrsub_vx_i16m2_m(pc_neg_mask, pc, 0, vl16);
 
-      /* pc = abs(p + pc) -> pc = (p + pc) < 0 ? -(p + pc) : p + pc */
-      asm volatile ("vadd.vv      v24, v24, v12");        /* pc = p + pc */
-      asm volatile ("vmslt.vx     v0, v24, zero");        /* set mask[i] if pc[i] < 0 */
-      asm volatile ("vrsub.vx     v24, v24, zero, v0.t"); /* invert negative values in pc; vd[i] = 0 - vs2[i] (if mask[i])
-                                                           * could be replaced by vneg in rvv >= 1.0
-                                                           */
+      /* pc = |p + pc| */
+      vint16m2_t p_plus_pc = __riscv_vadd_vv_i16m2(p, pc, vl16);
+      vbool8_t p_plus_pc_neg_mask = __riscv_vmslt_vx_i16m2_b8(p_plus_pc, 0, vl16);
+      pc = __riscv_vrsub_vx_i16m2_m(p_plus_pc_neg_mask, p_plus_pc, 0, vl16);
 
       /*
-       * if (pb < pa)
-       * {
-       *    pa = pb;
-       *    a = b;
-       *    // see (*1)
-       * }
+       * The key insight is that we want the minimum of pa, pb, pc.
+       * - If pa <= pb and pa <= pc, use a
+       * - Else if pb <= pc, use b
+       * - Else use c
        */
-      asm volatile ("vmslt.vv     v0, v20, v16");         /* set mask[i] if pb[i] < pa[i] */
-      asm volatile ("vmerge.vvm   v16, v16, v20, v0");    /* pa[i] = pb[i] (if mask[i]) */
 
-      /*
-       * if (pc < pa)
-       * {
-       *    a = c;
-       *    // see (*2)
-       * }
-       */
-      asm volatile ("vmslt.vv     v31, v24, v16");        /* set tmpmask[i] if pc[i] < pa[i] */
+      /* Find which predictor to use based on minimum absolute difference */
+      vbool8_t pa_le_pb = __riscv_vmsle_vv_i16m2_b8(pa, pb, vl16);
+      vbool8_t pa_le_pc = __riscv_vmsle_vv_i16m2_b8(pa, pc, vl16);
+      vbool8_t pb_le_pc = __riscv_vmsle_vv_i16m2_b8(pb, pc, vl16);
 
-      /* switch to narrow */
-      asm volatile ("vsetvli      zero, %0, e8, m1" : : "r" (bpp));
+      /* use_a = pa <= pb && pa <= pc */
+      vbool8_t use_a = __riscv_vmand_mm_b8(pa_le_pb, pa_le_pc, vl16);
 
-      /* (*1) */
-      asm volatile ("vmerge.vvm   v2, v2, v4, v0");       /* a = b (if mask[i]) */
+      /* use_b = !use_a && pb <= pc */
+      vbool8_t not_use_a = __riscv_vmnot_m_b8(use_a, vl16);
+      vbool8_t use_b = __riscv_vmand_mm_b8(not_use_a, pb_le_pc, vl16);
 
-      /* (*2) */
-      asm volatile ("vmand.mm     v0, v31, v31");         /* mask = tmpmask
-                                                           * vmand works for rvv 0.7 up to 1.0
-                                                           * could be replaced by vmcpy in 0.7.1/0.8.1
-                                                           * or vmmv.m in 1.0
-                                                           */
-      asm volatile ("vmerge.vvm   v2, v2, v6, v0");       /* a = c (if mask[i]) */
+      /* Switch back to e8m1 for final operations */
+      vl = __riscv_vsetvl_e8m1(bpp);
 
-      /* a += x */
-      asm volatile ("vadd.vv      v2, v2, v8");
+      /* Start with a, then conditionally replace with b or c */
+      vuint8m1_t result = a;
+      result = __riscv_vmerge_vvm_u8m1(result, b, use_b, vl);
+
+      /* use_c = !use_a && !use_b */
+      vbool8_t use_c = __riscv_vmnand_mm_b8(__riscv_vmor_mm_b8(use_a, use_b, vl), __riscv_vmor_mm_b8(use_a, use_b, vl), vl);
+      result = __riscv_vmerge_vvm_u8m1(result, c, use_c, vl);
+
+      /* a = result + x */
+      a = __riscv_vadd_vv_u8m1(result, x, vl);
 
       /* *row = a */
-      asm volatile ("vse8.v       v2, (%0)" : : "r" (row));
+      __riscv_vse8_v_u8m1(row, a, vl);
       row += bpp;
 
-      /* prepare next iteration (prev is already in a) */
-      /* c = b */
-      asm volatile ("vmv.v.v      v6, v4");
+      /* c = b for next iteration */
+      c = b;
    }
 }
-
 void
 png_read_filter_row_paeth3_rvv(png_row_infop row_info, png_bytep row,
     png_const_bytep prev_row)
@@ -349,8 +335,6 @@ png_read_filter_row_paeth3_rvv(png_row_infop row_info, png_bytep row,
    size_t len = row_info->rowbytes;
 
    png_read_filter_row_paeth_rvv(len, 3, row, prev_row);
-
-   PNG_UNUSED(prev_row)
 }
 
 void
@@ -360,9 +344,7 @@ png_read_filter_row_paeth4_rvv(png_row_infop row_info, png_bytep row,
    size_t len = row_info->rowbytes;
 
    png_read_filter_row_paeth_rvv(len, 4, row, prev_row);
-
-   PNG_UNUSED(prev_row)
 }
 
-#endif /* PNG_RISCV_RVV_IMPLEMENTATION */
-#endif /* READ */
+#endif /* PNG_RISCV_RVV_IMPLEMENTATION == 1 */
+#endif /* PNG_READ_SUPPORTED */

riscv/riscv_init.c

@@ -16,20 +16,6 @@
 
 #include <riscv_vector.h>
 
-#ifdef PNG_RISCV_RVV_CHECK_SUPPORTED /* Do run-time checks */
-/* WARNING: it is strongly recommended that you do not build libpng with
- * run-time checks for CPU features if at all possible. In the case of the
- * RISC-V Vector instructions there is no processor-specific way of detecting
- * the presence of the required support, therefore run-time detection is
- * extremely OS specific.
- *
- * You may set the macro PNG_RISCV_RVV_FILE to the file name of file containing
- * a fragment of C source code which defines the png_have_rvv function. There
- * are a number of implementations in contrib/riscv-rvv, but the only one that
- * has partial support is contrib/riscv-rvv/linux.c - a generic Linux
- * implementation which reads /proc/cpuinfo.
- */
-
 #include <signal.h>
 
 #ifndef PNG_RISCV_RVV_FILE
@@ -40,11 +26,10 @@
 #  endif
 #endif
 
-static int png_have_rvv(png_structp png_ptr);
+static int png_have_rvv();
 #ifdef PNG_RISCV_RVV_FILE
 #  include PNG_RISCV_RVV_FILE
 #endif
-#endif /* PNG_RISCV_RVV_CHECK_SUPPORTED */
 
 #ifndef PNG_ALIGNED_MEMORY_SUPPORTED
 #  error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
@@ -53,59 +38,16 @@ static int png_have_rvv(png_structp png_ptr);
 void
 png_init_filter_functions_rvv(png_structp pp, unsigned int bpp)
 {
-   /* The switch statement is compiled in for RISCV_RVV_API, the call to
-    * png_have_rvv is compiled in for RISCV_RVV_CHECK.  If both are
-    * defined the check is only performed if the API has not set the VECTOR
-    * option on or off explicitly.  In this case the check controls what
-    * happens.
-    */
    png_debug(1, "in png_init_filter_functions_rvv");
-#ifdef PNG_RISCV_RVV_API_SUPPORTED
-   switch ((pp->options >> PNG_RISCV_RVV) & 3)
-   {
-      case PNG_OPTION_UNSET:
-         /* Allow the run-time check to execute if it has been enabled -
-          * thus both API and CHECK can be turned on.  If it isn't supported
-          * this case will fall through to the 'default' below, which just
-          * returns.
-          */
-#endif /* PNG_RISCV_RVV_API_SUPPORTED */
-#ifdef PNG_RISCV_RVV_CHECK_SUPPORTED
-         {
+
    static volatile sig_atomic_t no_rvv = -1; /* not checked */
 
    if (no_rvv < 0)
-               no_rvv = !png_have_rvv(pp);
+      no_rvv = !png_have_rvv();
 
    if (no_rvv)
       return;
-         }
-#ifdef PNG_RISCV_RVV_API_SUPPORTED
-         break;
-#endif
-#endif /* PNG_RISCV_RVV_CHECK_SUPPORTED */
 
-#ifdef PNG_RISCV_RVV_API_SUPPORTED
-      default: /* OFF or INVALID */
-         return;
-
-      case PNG_OPTION_ON:
-         /* Option turned on */
-         break;
-   }
-#endif /* PNG_RISCV_RVV_API_SUPPORTED */
-
-   /* IMPORTANT: any new external functions used here must be declared using
-    * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the
-    * 'prefix' option to configure works:
-    *
-    *    ./configure --with-libpng-prefix=foobar_
-    *
-    * Verify you have got this right by running the above command, doing a build
-    * and examining pngprefix.h; it must contain a #define for every external
-    * function you add.  (Notice that this happens automatically for the
-    * initialization function.)
-    */
    pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_rvv;
 
    if (bpp == 3)

scripts/libpng-config-head.in

@@ -11,7 +11,7 @@
 
 # Modeled after libxml-config.
 
-version=1.6.49
+version=1.6.51.git
 prefix=""
 libdir=""
 libs=""

scripts/libpng.pc.in

@@ -5,6 +5,6 @@ includedir=@includedir@/libpng16
 
 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.6.49
+Version: 1.6.51.git
 Libs: -L${libdir} -lpng16
 Cflags: -I${includedir}

scripts/pnglibconf.h.prebuilt

@@ -1,6 +1,6 @@
 /* pnglibconf.h - library build configuration */
 
-/* libpng version 1.6.49 */
+/* libpng version 1.6.51.git */
 
 /* Copyright (c) 2018-2025 Cosmin Truta */
 /* Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson */

test-driver

@@ -1,7 +1,7 @@
 #! /bin/sh
 # test-driver - basic testsuite driver script.
 
-scriptversion=2024-12-03.03; # UTC
+scriptversion=2025-06-18.21; # UTC
 
 # Copyright (C) 2011-2025 Free Software Foundation, Inc.
 #
@@ -154,7 +154,7 @@ echo ":copy-in-global-log: $gcopy" >> $trs_file
 # sh-indentation: 2
 # eval: (add-hook 'before-save-hook 'time-stamp nil t)
 # time-stamp-start: "scriptversion="
-# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-format: "%Y-%02m-%02d.%02H"
 # time-stamp-time-zone: "UTC0"
 # time-stamp-end: "; # UTC"
 # End: