[clang] 4aa87a1 - [OpenMP][AMDGPU] Add 'uniform-work-group' attribute to OpenMP kernels

[Joseph Huber via cfe-commits]

Author: Joseph Huber
Date: 2022-10-06T18:22:09-05:00
New Revision: 4aa87a131f93de73b8e245021af0294545d063c5

URL: https://github.com/llvm/llvm-project/commit/4aa87a131f93de73b8e245021af0294545d063c5
DIFF: https://github.com/llvm/llvm-project/commit/4aa87a131f93de73b8e245021af0294545d063c5.diff

LOG: [OpenMP][AMDGPU] Add 'uniform-work-group' attribute to OpenMP kernels

The `cl-uniform-work-group` attribute asserts that the global work-size
be a multiple of the work-group specified work group size. This should
allow optimizations. It is already present by default in the AMD
compiler and for HIP kernels so it should be safe to allow this for
OpenMP kernels by default.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D135374

Added: 
    

Modified: 
    clang/lib/CodeGen/TargetInfo.cpp
    clang/test/OpenMP/amdgcn-attributes.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index 02bcf8a19bbfb..74997f0f9e9dc 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -9423,8 +9423,12 @@ void AMDGPUTargetCodeGenInfo::setTargetAttributes(
 
   const bool IsHIPKernel =
       M.getLangOpts().HIP && FD && FD->hasAttr<CUDAGlobalAttr>();
+  const bool IsOpenMPkernel =
+      M.getLangOpts().OpenMPIsDevice &&
+      (F->getCallingConv() == llvm::CallingConv::AMDGPU_KERNEL);
 
-  if (IsHIPKernel)
+  // TODO: This should be moved to language specific attributes instead.
+  if (IsHIPKernel || IsOpenMPkernel)
     F->addFnAttr("uniform-work-group-size", "true");
 
   if (M.getContext().getTargetInfo().allowAMDGPUUnsafeFPAtomics())

diff  --git a/clang/test/OpenMP/amdgcn-attributes.cpp b/clang/test/OpenMP/amdgcn-attributes.cpp
index ab11bf765b9bc..506989a8de138 100644
--- a/clang/test/OpenMP/amdgcn-attributes.cpp
+++ b/clang/test/OpenMP/amdgcn-attributes.cpp
@@ -32,10 +32,10 @@ int callable(int x) {
   return x + 1;
 }
 
-  // DEFAULT: attributes #0 = { convergent noinline norecurse nounwind optnone "frame-pointer"="none" "kernel" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
-  // CPU: attributes #0 = { convergent noinline norecurse nounwind optnone "frame-pointer"="none" "kernel" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="gfx900" "target-features"="+16-bit-insts,+ci-insts,+dpp,+flat-address-space,+gfx8-insts,+gfx9-insts,+s-memrealtime,+s-memtime-inst" }
-  // NOIEEE: attributes #0 = { convergent noinline norecurse nounwind optnone "amdgpu-ieee"="false" "frame-pointer"="none" "kernel" "min-legal-vector-width"="0" "no-nans-fp-math"="true" "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
-  // UNSAFEATOMIC: attributes #0 = { convergent noinline norecurse nounwind optnone "amdgpu-unsafe-fp-atomics"="true" "frame-pointer"="none" "kernel" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
+// DEFAULT: attributes #0 = { convergent noinline norecurse nounwind optnone "frame-pointer"="none" "kernel" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "uniform-work-group-size"="true" }
+// CPU: attributes #0 = { convergent noinline norecurse nounwind optnone "frame-pointer"="none" "kernel" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="gfx900" "target-features"="+16-bit-insts,+ci-insts,+dpp,+flat-address-space,+gfx8-insts,+gfx9-insts,+s-memrealtime,+s-memtime-inst" "uniform-work-group-size"="true" }
+// NOIEEE: attributes #0 = { convergent noinline norecurse nounwind optnone "amdgpu-ieee"="false" "frame-pointer"="none" "kernel" "min-legal-vector-width"="0" "no-nans-fp-math"="true" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "uniform-work-group-size"="true" }
+// UNSAFEATOMIC: attributes #0 = { convergent noinline norecurse nounwind optnone "amdgpu-unsafe-fp-atomics"="true" "frame-pointer"="none" "kernel" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "uniform-work-group-size"="true" }
 
 // DEFAULT: attributes #1 = { convergent mustprogress noinline nounwind optnone "frame-pointer"="none" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
 // CPU: attributes #1 = { convergent mustprogress noinline nounwind optnone "frame-pointer"="none" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="gfx900" "target-features"="+16-bit-insts,+ci-insts,+dpp,+flat-address-space,+gfx8-insts,+gfx9-insts,+s-memrealtime,+s-memtime-inst" }