Emit Int64Atomics for imageAtomicStore

This covers a corner case wherein imageAtomicStore is used exclusively.
The proxy type for imageAtomicStore is inferred from the image type.

Fix #2975.

SPIRV/GlslangToSpv.cpp

@@ -5581,10 +5581,12 @@ spv::Id TGlslangToSpvTraverser::createImageTextureFunctionCall(glslang::TIntermO
             operands.push_back(sample);
 
             spv::Id resultTypeId;
+            glslang::TBasicType typeProxy = node->getBasicType();
             // imageAtomicStore has a void return type so base the pointer type on
             // the type of the value operand.
             if (node->getOp() == glslang::EOpImageAtomicStore) {
                 resultTypeId = builder.makePointer(spv::StorageClassImage, builder.getTypeId(*opIt));
+                typeProxy = node->getAsAggregate()->getSequence()[0]->getAsTyped()->getType().getSampler().type;
             } else {
                 resultTypeId = builder.makePointer(spv::StorageClassImage, resultType());
             }
@@ -5598,7 +5600,7 @@ spv::Id TGlslangToSpvTraverser::createImageTextureFunctionCall(glslang::TIntermO
             for (; opIt != arguments.end(); ++opIt)
                 operands.push_back(*opIt);
 
-            return createAtomicOperation(node->getOp(), precision, resultType(), operands, node->getBasicType(),
+            return createAtomicOperation(node->getOp(), precision, resultType(), operands, typeProxy,
                 lvalueCoherentFlags);
         }
     }

Test/baseResults/spv.imageAtomic64.comp.out

@@ -0,0 +1,58 @@
+spv.imageAtomic64.comp
+// Module Version 10000
+// Generated by (magic number): 8000a
+// Id's are bound by 28
+
+                              Capability Shader
+                              Capability Int64
+                              Capability Int64Atomics
+                              Capability Int64ImageEXT
+                              Extension  "SPV_EXT_shader_image_int64"
+               1:             ExtInstImport  "GLSL.std.450"
+                              MemoryModel Logical GLSL450
+                              EntryPoint GLCompute 4  "main"
+                              ExecutionMode 4 LocalSize 1 1 1
+                              Source GLSL 450
+                              SourceExtension  "GL_EXT_shader_explicit_arithmetic_types_int64"
+                              SourceExtension  "GL_EXT_shader_image_int64"
+                              SourceExtension  "GL_KHR_memory_scope_semantics"
+                              Name 4  "main"
+                              Name 9  "z"
+                              Name 14  "ssbo"
+                              MemberName 14(ssbo) 0  "y"
+                              Name 16  ""
+                              Decorate 9(z) DescriptorSet 0
+                              Decorate 9(z) Binding 1
+                              MemberDecorate 14(ssbo) 0 Offset 0
+                              Decorate 14(ssbo) BufferBlock
+                              Decorate 16 DescriptorSet 0
+                              Decorate 16 Binding 0
+               2:             TypeVoid
+               3:             TypeFunction 2
+               6:             TypeInt 64 0
+               7:             TypeImage 6(int64_t) 2D nonsampled format:R64ui
+               8:             TypePointer UniformConstant 7
+            9(z):      8(ptr) Variable UniformConstant
+              10:             TypeInt 32 1
+              11:             TypeVector 10(int) 2
+              12:     10(int) Constant 1
+              13:   11(ivec2) ConstantComposite 12 12
+        14(ssbo):             TypeStruct 6(int64_t)
+              15:             TypePointer Uniform 14(ssbo)
+              16:     15(ptr) Variable Uniform
+              17:     10(int) Constant 0
+              18:             TypePointer Uniform 6(int64_t)
+              21:     10(int) Constant 2048
+              22:             TypeInt 32 0
+              23:     22(int) Constant 0
+              24:             TypePointer Image 6(int64_t)
+              26:     22(int) Constant 1
+              27:     22(int) Constant 2048
+         4(main):           2 Function None 3
+               5:             Label
+              19:     18(ptr) AccessChain 16 17
+              20:  6(int64_t) Load 19
+              25:     24(ptr) ImageTexelPointer 9(z) 13 23
+                              AtomicStore 25 12 27 20
+                              Return
+                              FunctionEnd

Test/spv.imageAtomic64.comp

@@ -0,0 +1,12 @@
+#version 450
+#extension GL_EXT_shader_explicit_arithmetic_types_int64 : enable
+#extension GL_EXT_shader_image_int64 : enable
+#extension GL_KHR_memory_scope_semantics : enable
+
+layout(set = 0, binding = 0) buffer ssbo { uint64_t y; };
+layout(set = 0, binding = 1, r64ui) uniform u64image2D z;
+
+void main() {
+    // Test imageAtomicStore exclusively. Do NOT add other atomic operations to this test.
+    imageAtomicStore(z, ivec2(1, 1), y, gl_ScopeDevice, gl_StorageSemanticsImage, gl_SemanticsRelaxed);
+}

gtests/Spv.FromFile.cpp

@@ -444,6 +444,7 @@ INSTANTIATE_TEST_SUITE_P(
         "spv.textureBuffer.vert",
         "spv.image.frag",
         "spv.imageAtomic64.frag",
+        "spv.imageAtomic64.comp",
         "spv.types.frag",
         "spv.uint.frag",
         "spv.uniformArray.frag",