From fc6aea37483446372425aca8471f0e8bf7c3a910 Mon Sep 17 00:00:00 2001 From: amidescent <221220072+amidescent@users.noreply.github.com> Date: Sat, 9 Aug 2025 12:30:30 -0300 Subject: [SPIR-V] Emit control flags for `branch/flatten` decorations (#8134) Co-authored-by: Jay Kwak <82421531+jkwak-work@users.noreply.github.com> Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com> --- source/slang/slang-emit-spirv.cpp | 23 +++++++++++++++++++++-- tests/bugs/branch-attribute.slang | 9 ++++++--- tests/bugs/branch-switch-attribute.slang | 6 ++++-- 3 files changed, 31 insertions(+), 7 deletions(-) diff --git a/source/slang/slang-emit-spirv.cpp b/source/slang/slang-emit-spirv.cpp index 0449c6b88..aa4c3bec8 100644 --- a/source/slang/slang-emit-spirv.cpp +++ b/source/slang/slang-emit-spirv.cpp @@ -3962,6 +3962,17 @@ struct SPIRVEmitContext : public SourceEmitterBase, public SPIRVEmitSharedContex } } + SpvSelectionControlMask getSpvBranchSelectionControl(IRInst* inst) + { + if (inst->findDecorationImpl(kIROp_BranchDecoration)) + return SpvSelectionControlDontFlattenMask; + + if (inst->findDecorationImpl(kIROp_FlattenDecoration)) + return SpvSelectionControlFlattenMask; + + return SpvSelectionControlMaskNone; + } + // The instructions that appear inside the basic blocks of // functions are what we will call "local" instructions. // @@ -4269,7 +4280,11 @@ struct SPIRVEmitContext : public SourceEmitterBase, public SPIRVEmitSharedContex { auto ifelseInst = as(inst); auto afterBlockID = getIRInstSpvID(ifelseInst->getAfterBlock()); - emitOpSelectionMerge(parent, nullptr, afterBlockID, SpvSelectionControlMaskNone); + emitOpSelectionMerge( + parent, + nullptr, + afterBlockID, + getSpvBranchSelectionControl(ifelseInst)); auto falseLabel = ifelseInst->getFalseBlock(); result = emitOpBranchConditional( parent, @@ -4284,7 +4299,11 @@ struct SPIRVEmitContext : public SourceEmitterBase, public SPIRVEmitSharedContex { auto switchInst = as(inst); auto mergeBlockID = getIRInstSpvID(switchInst->getBreakLabel()); - emitOpSelectionMerge(parent, nullptr, mergeBlockID, SpvSelectionControlMaskNone); + emitOpSelectionMerge( + parent, + nullptr, + mergeBlockID, + getSpvBranchSelectionControl(switchInst)); result = emitInstCustomOperandFunc( parent, inst, diff --git a/tests/bugs/branch-attribute.slang b/tests/bugs/branch-attribute.slang index 17e30a278..95288ecfa 100644 --- a/tests/bugs/branch-attribute.slang +++ b/tests/bugs/branch-attribute.slang @@ -1,10 +1,13 @@ -//TEST:SIMPLE(filecheck=CHECK): -target hlsl -profile cs_5_0 -entry computeMain +//TEST:SIMPLE(filecheck=HLSL): -target hlsl -profile cs_5_0 -entry computeMain +//TEST:SIMPLE(filecheck=SPIRV): -target spirv -O0 //TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name outputBuffer RWStructuredBuffer outputBuffer; -// CHECK: [branch] -// CHECK: [flatten] +// HLSL: [branch] +// HLSL: [flatten] +// SPIRV: OpSelectionMerge {{.*}} DontFlatten +// SPIRV: OpSelectionMerge {{.*}} Flatten [numthreads(4, 1, 1)] void computeMain(int3 dispatchThreadID : SV_DispatchThreadID) diff --git a/tests/bugs/branch-switch-attribute.slang b/tests/bugs/branch-switch-attribute.slang index 761b80e9e..5fe82b7e4 100644 --- a/tests/bugs/branch-switch-attribute.slang +++ b/tests/bugs/branch-switch-attribute.slang @@ -1,9 +1,11 @@ -//TEST:SIMPLE(filecheck=CHECK): -target hlsl -profile cs_5_0 -entry computeMain +//TEST:SIMPLE(filecheck=HLSL): -target hlsl -profile cs_5_0 -entry computeMain +//TEST:SIMPLE(filecheck=SPIRV): -target spirv -O0 //TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name outputBuffer RWStructuredBuffer outputBuffer; -// CHECK: [branch] +// HLSL: [branch] +// SPIRV: OpSelectionMerge {{.*}} DontFlatten [numthreads(4, 1, 1)] void computeMain(int3 dispatchThreadID : SV_DispatchThreadID) -- cgit v1.2.3