mewin/glslang
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Generate correctly structured do-while loops.

Browse Source 
The loop test is always emitted before the loop body.

For do-while loops, use a phi node to track whether we're
on the first loop iteration, and only check the loop test
on the second and subsequent iterations.

For do-while loops, the loop test branch no longer occurs
at the top of the loop, so it must get its own selection
merge instruction.

A block can't be the target of more than one merge instruction.
So when the loop test executes after the body (as in do-while in GLSL)
we need to introduce a dummy block to be the target of the selection
merge just before the loop test conditional branch.

The other arm of the branch exits the loop and hence is the
"break block" exception in the structured control flow rules.
This commit is contained in:
David Neto
2015-07-15 16:21:26 -04:00
parent 51b31b5785
commit c22f37cfb4
8 changed files with 1486 additions and 1373 deletions
Download Patch File Download Diff File Expand all files Collapse all files

59
Test/baseResults/spv.do-simple.vert.out
View File

@@ -5,7 +5,7 @@ Linked vertex stage:
// Module Version 99
// Generated by (magic number): 51a00bb
// Id's are bound by 26
// Id's are bound by 30
Source ESSL 300
1: ExtInstImport "GLSL.std.450"
@@ -13,45 +13,52 @@ Linked vertex stage:
EntryPoint Vertex 4
Name 4 "main"
Name 9 "i"
Name 24 "gl_VertexID"
Name 25 "gl_InstanceID"
Name 28 "gl_VertexID"
Name 29 "gl_InstanceID"
Decorate 9(i) PrecisionHigh
Decorate 24(gl_VertexID) PrecisionHigh
Decorate 24(gl_VertexID) BuiltIn VertexId
Decorate 24(gl_VertexID) NoStaticUse
Decorate 25(gl_InstanceID) PrecisionHigh
Decorate 25(gl_InstanceID) BuiltIn InstanceId
Decorate 25(gl_InstanceID) NoStaticUse
Decorate 28(gl_VertexID) PrecisionHigh
Decorate 28(gl_VertexID) BuiltIn VertexId
Decorate 28(gl_VertexID) NoStaticUse
Decorate 29(gl_InstanceID) PrecisionHigh
Decorate 29(gl_InstanceID) BuiltIn InstanceId
Decorate 29(gl_InstanceID) NoStaticUse
2: TypeVoid
3: TypeFunction 2
7: TypeInt 32 1
8: TypePointer Function 7(int)
10: 7(int) Constant 0
16: 7(int) Constant 1
19: 7(int) Constant 10
20: TypeBool
23: TypePointer Input 7(int)
24(gl_VertexID): 23(ptr) Variable Input
25(gl_InstanceID): 23(ptr) Variable Input
14: TypeBool
15: 14(bool) ConstantTrue
20: 7(int) Constant 10
24: 7(int) Constant 1
26: 14(bool) ConstantFalse
27: TypePointer Input 7(int)
28(gl_VertexID): 27(ptr) Variable Input
29(gl_InstanceID): 27(ptr) Variable Input
4(main): 2 Function None 3
5: Label
9(i): 8(ptr) Variable Function
Store 9(i) 10
Branch 11
11: Label
13: 14(bool) Phi 15 5 26 17
LoopMerge 12 None
Branch 13
13: Label
15: 7(int) Load 9(i)
17: 7(int) IAdd 15 16
Store 9(i) 17
Branch 14
14: Label
18: 7(int) Load 9(i)
21: 20(bool) SLessThan 18 19
BranchConditional 21 22 12
Branch 16
16: Label
SelectionMerge 17 None
BranchConditional 13 17 18
18: Label
19: 7(int) Load 9(i)
21: 14(bool) SLessThan 19 20
SelectionMerge 22 None
BranchConditional 21 22 12
22: Label
Branch 11
Branch 17
17: Label
23: 7(int) Load 9(i)
25: 7(int) IAdd 23 24
Store 9(i) 25
Branch 11
12: Label
Branch 6
6: Label