SPV 1.4: Use OpSelect for trivial typed non-scalar/vector expressions.

This commit is contained in:
John Kessenich 2019-01-10 18:23:06 +07:00
parent cfea59d357
commit 0c1e71a123
4 changed files with 209 additions and 5 deletions

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@ -2615,6 +2615,19 @@ bool TGlslangToSpvTraverser::visitAggregate(glslang::TVisit visit, glslang::TInt
// next layer copies r-values into memory to use the access-chain mechanism
bool TGlslangToSpvTraverser::visitSelection(glslang::TVisit /* visit */, glslang::TIntermSelection* node)
{
// see if OpSelect can handle it
const auto isOpSelectable = [&]() {
if (node->getBasicType() == glslang::EbtVoid)
return false;
// OpSelect can do all other types starting with SPV 1.4
if (glslangIntermediate->getSpv().spv < glslang::EShTargetSpv_1_4) {
// pre-1.4, only scalars and vectors can be handled
if ((!node->getType().isScalar() && !node->getType().isVector()))
return false;
}
return true;
};
// See if it simple and safe, or required, to execute both sides.
// Crucially, side effects must be either semantically required or avoided,
// and there are performance trade-offs.
@ -2633,9 +2646,7 @@ bool TGlslangToSpvTraverser::visitSelection(glslang::TVisit /* visit */, glslang
// if not required to execute both, decide based on performance/practicality...
// see if OpSelect can handle it
if ((!node->getType().isScalar() && !node->getType().isVector()) ||
node->getBasicType() == glslang::EbtVoid)
if (!isOpSelectable())
return false;
assert(node->getType() == node->getTrueBlock() ->getAsTyped()->getType() &&
@ -2672,14 +2683,16 @@ bool TGlslangToSpvTraverser::visitSelection(glslang::TVisit /* visit */, glslang
// emit code to select between trueValue and falseValue
// see if OpSelect can handle it
if (node->getType().isScalar() || node->getType().isVector()) {
if (isOpSelectable()) {
// Emit OpSelect for this selection.
// smear condition to vector, if necessary (AST is always scalar)
if (builder.isVector(trueValue))
// Before 1.4, smear like for mix(), starting with 1.4, keep it scalar
if (glslangIntermediate->getSpv().spv < glslang::EShTargetSpv_1_4 && builder.isVector(trueValue)) {
condition = builder.smearScalar(spv::NoPrecision, condition,
builder.makeVectorType(builder.makeBoolType(),
builder.getNumComponents(trueValue)));
}
// OpSelect
result = builder.createTriOp(spv::OpSelect,

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@ -0,0 +1,153 @@
spv.1.4.OpSelect.frag
Validation failed
// Module Version 10400
// Generated by (magic number): 80007
// Id's are bound by 98
Capability Shader
1: ExtInstImport "GLSL.std.450"
MemoryModel Logical GLSL450
EntryPoint Fragment 4 "main" 17 20 82 84
ExecutionMode 4 OriginUpperLeft
Source GLSL 450
Name 4 "main"
Name 6 "fun1("
Name 8 "fun2("
Name 12 "f1"
Name 14 "f2"
Name 17 "outv"
Name 20 "cond"
Name 30 "iv1"
Name 34 "iv2"
Name 53 "m1"
Name 59 "m2"
Name 75 "S1"
MemberName 75(S1) 0 "a"
MemberName 75(S1) 1 "b"
Name 77 "fv"
Name 82 "in1"
Name 84 "in2"
Decorate 17(outv) Location 0
Decorate 20(cond) Flat
Decorate 20(cond) Location 4
Decorate 82(in1) Flat
Decorate 82(in1) Location 0
Decorate 84(in2) Flat
Decorate 84(in2) Location 2
2: TypeVoid
3: TypeFunction 2
10: TypeFloat 32
11: TypePointer Function 10(float)
13: 10(float) Constant 1065353216
15: 10(float) Constant 1073741824
16: TypePointer Output 10(float)
17(outv): 16(ptr) Variable Output
18: TypeInt 32 1
19: TypePointer Input 18(int)
20(cond): 19(ptr) Variable Input
22: 18(int) Constant 8
23: TypeBool
28: TypeVector 18(int) 4
29: TypePointer Function 28(ivec4)
39: 18(int) Constant 0
44: TypeInt 32 0
45: 44(int) Constant 2
50: TypeVector 10(float) 3
51: TypeMatrix 50(fvec3) 3
52: TypePointer Function 51
54: 10(float) Constant 0
55: 50(fvec3) ConstantComposite 13 54 54
56: 50(fvec3) ConstantComposite 54 13 54
57: 50(fvec3) ConstantComposite 54 54 13
58: 51 ConstantComposite 55 56 57
60: 50(fvec3) ConstantComposite 15 54 54
61: 50(fvec3) ConstantComposite 54 15 54
62: 50(fvec3) ConstantComposite 54 54 15
63: 51 ConstantComposite 60 61 62
65: 18(int) Constant 20
70: 18(int) Constant 2
71: 44(int) Constant 1
75(S1): TypeStruct 10(float) 18(int)
76: TypePointer Function 75(S1)
79: 18(int) Constant 5
81: TypePointer Input 75(S1)
82(in1): 81(ptr) Variable Input
84(in2): 81(ptr) Variable Input
4(main): 2 Function None 3
5: Label
12(f1): 11(ptr) Variable Function
14(f2): 11(ptr) Variable Function
30(iv1): 29(ptr) Variable Function
34(iv2): 29(ptr) Variable Function
53(m1): 52(ptr) Variable Function
59(m2): 52(ptr) Variable Function
77(fv): 76(ptr) Variable Function
Store 12(f1) 13
Store 14(f2) 15
21: 18(int) Load 20(cond)
24: 23(bool) SLessThan 21 22
25: 10(float) Load 12(f1)
26: 10(float) Load 14(f2)
27: 10(float) Select 24 25 26
Store 17(outv) 27
31: 10(float) Load 12(f1)
32: 18(int) ConvertFToS 31
33: 28(ivec4) CompositeConstruct 32 32 32 32
Store 30(iv1) 33
35: 10(float) Load 14(f2)
36: 18(int) ConvertFToS 35
37: 28(ivec4) CompositeConstruct 36 36 36 36
Store 34(iv2) 37
38: 18(int) Load 20(cond)
40: 23(bool) SGreaterThan 38 39
41: 28(ivec4) Load 30(iv1)
42: 28(ivec4) Load 34(iv2)
43: 28(ivec4) Select 40 41 42
46: 18(int) CompositeExtract 43 2
47: 10(float) ConvertSToF 46
48: 10(float) Load 17(outv)
49: 10(float) FMul 48 47
Store 17(outv) 49
Store 53(m1) 58
Store 59(m2) 63
64: 18(int) Load 20(cond)
66: 23(bool) SLessThan 64 65
67: 51 Load 53(m1)
68: 51 Load 59(m2)
69: 51 Select 66 67 68
72: 10(float) CompositeExtract 69 2 1
73: 10(float) Load 17(outv)
74: 10(float) FMul 73 72
Store 17(outv) 74
78: 18(int) Load 20(cond)
80: 23(bool) SGreaterThan 78 79
83: 75(S1) Load 82(in1)
85: 75(S1) Load 84(in2)
86: 75(S1) Select 80 83 85
Store 77(fv) 86
87: 11(ptr) AccessChain 77(fv) 39
88: 10(float) Load 87
89: 10(float) Load 17(outv)
90: 10(float) FMul 89 88
Store 17(outv) 90
91: 18(int) Load 20(cond)
92: 23(bool) SGreaterThan 91 39
SelectionMerge 94 None
BranchConditional 92 93 96
93: Label
95: 2 FunctionCall 6(fun1()
Branch 94
96: Label
97: 2 FunctionCall 8(fun2()
Branch 94
94: Label
Return
FunctionEnd
6(fun1(): 2 Function None 3
7: Label
Return
FunctionEnd
8(fun2(): 2 Function None 3
9: Label
Return
FunctionEnd

37
Test/spv.1.4.OpSelect.frag Executable file
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@ -0,0 +1,37 @@
#version 450
struct S1 {
float a;
int b;
};
layout(location = 0) flat in S1 in1;
layout(location = 2) flat in S1 in2;
layout(location = 4) flat in int cond;
layout(location = 0) out float outv;
void fun1(){}
void fun2(){}
void main()
{
// glslang will only make OpSelect for very trivial looking expressions
float f1 = 1.0;
float f2 = 2.0;
outv = cond < 8 ? f1 : f2; // in all versions
ivec4 iv1 = ivec4(f1);
ivec4 iv2 = ivec4(f2);
outv *= (cond > 0 ? iv1 : iv2).z; // in all versions, but in 1.4 as scalar condition, not smeared ala mix()
mat3 m1 = mat3(1.0);
mat3 m2 = mat3(2.0);
outv *= (cond < 20 ? m1 : m2)[2][1]; // in 1.4, but not before
S1 fv = cond > 5 ? in1 : in2; // in 1.4, but not before
outv *= fv.a;
cond > 0 ? fun1() : fun2(); // not allowed by any version
}

1
gtests/Spv.FromFile.cpp Normal file → Executable file
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@ -466,6 +466,7 @@ INSTANTIATE_TEST_CASE_P(
Glsl, CompileToSpirv14Test,
::testing::ValuesIn(std::vector<std::string>({
"spv.1.4.OpEntryPoint.frag",
"spv.1.4.OpSelect.frag",
})),
FileNameAsCustomTestSuffix
);