AMDGPU: Don't promote alloca to LDS for leaf functions

[arsenm]

Summary

LDS use in leaf functions not currently handled.

[arsenm]

ping

[arsenm]

ping

[arsenm]

ping

[arsenm]

ping

[kzhuravl]

LGTM.

[arsenm]

r301958

lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp

void AMDGPUPromoteAlloca::handleAlloca(AllocaInst &I) {
   DEBUG(dbgs() << "Trying to promote " << I << '\n');
 
   if (tryPromoteAllocaToVector(&I)) {
     DEBUG(dbgs() << " alloca is not a candidate for vectorization.\n");
     return;
   }
 
   const Function &ContainingFunction = *I.getParent()->getParent();
+  CallingConv::ID CC = ContainingFunction.getCallingConv();
 
   // Don't promote the alloca to LDS for shader calling conventions as the work
   // item ID intrinsics are not supported for these calling conventions.
   // Furthermore not all LDS is available for some of the stages.
-  if (AMDGPU::isShader(ContainingFunction.getCallingConv()))
+  switch (CC) {
+  case CallingConv::AMDGPU_KERNEL:
+  case CallingConv::SPIR_KERNEL:
+    break;
+  default:
+    DEBUG(dbgs() << " promote alloca to LDS not supported with calling convention.\n");
     return;
+  }
 
   const AMDGPUSubtarget &ST =
     TM->getSubtarget<AMDGPUSubtarget>(ContainingFunction);
   // FIXME: We should also try to get this value from the reqd_work_group_size
   // function attribute if it is available.
   unsigned WorkGroupSize = ST.getFlatWorkGroupSizes(ContainingFunction).second;
 
   const DataLayout &DL = Mod->getDataLayout();

test/CodeGen/AMDGPU/promote-alloca-calling-conv.ll

+; RUN: opt -S -mtriple=amdgcn-unknown-unknown -amdgpu-promote-alloca < %s | FileCheck -check-prefix=IR %s
+; RUN: llc -march=amdgcn -mcpu=tonga < %s | FileCheck -check-prefix=ASM %s
+
+; IR-LABEL: define amdgpu_vs void @promote_alloca_shaders(i32 addrspace(1)* inreg %out, i32 addrspace(1)* inreg %in) #0 {
+; IR: alloca [5 x i32]
+; ASM-LABEL: {{^}}promote_alloca_shaders:
+; ASM: ; LDSByteSize: 0 bytes/workgroup (compile time only)
+
+define amdgpu_vs void @promote_alloca_shaders(i32 addrspace(1)* inreg %out, i32 addrspace(1)* inreg %in) #0 {
+entry:
+  %stack = alloca [5 x i32], align 4
+  %tmp0 = load i32, i32 addrspace(1)* %in, align 4
+  %arrayidx1 = getelementptr inbounds [5 x i32], [5 x i32]* %stack, i32 0, i32 %tmp0
+  store i32 4, i32* %arrayidx1, align 4
+  %arrayidx2 = getelementptr inbounds i32, i32 addrspace(1)* %in, i32 1
+  %tmp1 = load i32, i32 addrspace(1)* %arrayidx2, align 4
+  %arrayidx3 = getelementptr inbounds [5 x i32], [5 x i32]* %stack, i32 0, i32 %tmp1
+  store i32 5, i32* %arrayidx3, align 4
+  %arrayidx4 = getelementptr inbounds [5 x i32], [5 x i32]* %stack, i32 0, i32 0
+  %tmp2 = load i32, i32* %arrayidx4, align 4
+  store i32 %tmp2, i32 addrspace(1)* %out, align 4
+  %arrayidx5 = getelementptr inbounds [5 x i32], [5 x i32]* %stack, i32 0, i32 1
+  %tmp3 = load i32, i32* %arrayidx5
+  %arrayidx6 = getelementptr inbounds i32, i32 addrspace(1)* %out, i32 1
+  store i32 %tmp3, i32 addrspace(1)* %arrayidx6
+  ret void
+}
+
+; OPT-LABEL: @promote_to_vector_call_c(
+; OPT-NOT: alloca
+; OPT: extractelement <2 x i32> %{{[0-9]+}}, i32 %in
+; ASM: ; LDSByteSize: 0 bytes/workgroup (compile time only)
+define void @promote_to_vector_call_c(i32 addrspace(1)* %out, i32 %in) #0 {
+entry:
+  %tmp = alloca [2 x i32]
+  %tmp1 = getelementptr [2 x i32], [2 x i32]* %tmp, i32 0, i32 0
+  %tmp2 = getelementptr [2 x i32], [2 x i32]* %tmp, i32 0, i32 1
+  store i32 0, i32* %tmp1
+  store i32 1, i32* %tmp2
+  %tmp3 = getelementptr [2 x i32], [2 x i32]* %tmp, i32 0, i32 %in
+  %tmp4 = load i32, i32* %tmp3
+  %tmp5 = call i32 @llvm.amdgcn.workitem.id.x()
+  %tmp6 = add i32 %tmp4, %tmp5
+  store i32 %tmp6, i32 addrspace(1)* %out
+  ret void
+}
+
+; OPT-LABEL: @no_promote_to_lds_c(
+; OPT: alloca
+; ASM: ; LDSByteSize: 0 bytes/workgroup (compile time only)
+define void @no_promote_to_lds(i32 addrspace(1)* nocapture %out, i32 addrspace(1)* nocapture %in) #0 {
+entry:
+  %stack = alloca [5 x i32], align 4
+  %0 = load i32, i32 addrspace(1)* %in, align 4
+  %arrayidx1 = getelementptr inbounds [5 x i32], [5 x i32]* %stack, i32 0, i32 %0
+  store i32 4, i32* %arrayidx1, align 4
+  %arrayidx2 = getelementptr inbounds i32, i32 addrspace(1)* %in, i32 1
+  %1 = load i32, i32 addrspace(1)* %arrayidx2, align 4
+  %arrayidx3 = getelementptr inbounds [5 x i32], [5 x i32]* %stack, i32 0, i32 %1
+  store i32 5, i32* %arrayidx3, align 4
+  %arrayidx10 = getelementptr inbounds [5 x i32], [5 x i32]* %stack, i32 0, i32 0
+  %2 = load i32, i32* %arrayidx10, align 4
+  store i32 %2, i32 addrspace(1)* %out, align 4
+  %arrayidx12 = getelementptr inbounds [5 x i32], [5 x i32]* %stack, i32 0, i32 1
+  %3 = load i32, i32* %arrayidx12
+  %arrayidx13 = getelementptr inbounds i32, i32 addrspace(1)* %out, i32 1
+  store i32 %3, i32 addrspace(1)* %arrayidx13
+  ret void
+}
+
+declare i32 @llvm.amdgcn.workitem.id.x() #1
+
+attributes #0 = { nounwind "amdgpu-max-work-group-size"="64" }
+attributes #1 = { nounwind readnone }

test/CodeGen/AMDGPU/promote-alloca-shaders.ll

-; RUN: opt -S -mtriple=amdgcn-unknown-unknown -amdgpu-promote-alloca < %s | FileCheck -check-prefix=IR %s
-; RUN: llc -march=amdgcn -mcpu=tonga < %s | FileCheck -check-prefix=ASM %s
-
-; IR-LABEL: define amdgpu_vs void @promote_alloca_shaders(i32 addrspace(1)* inreg %out, i32 addrspace(1)* inreg %in) #0 {
-; IR: alloca [5 x i32]
-; ASM-LABEL: {{^}}promote_alloca_shaders:
-; ASM: ; LDSByteSize: 0 bytes/workgroup (compile time only)
-
-define amdgpu_vs void @promote_alloca_shaders(i32 addrspace(1)* inreg %out, i32 addrspace(1)* inreg %in) #0 {
-entry:
-  %stack = alloca [5 x i32], align 4
-  %tmp0 = load i32, i32 addrspace(1)* %in, align 4
-  %arrayidx1 = getelementptr inbounds [5 x i32], [5 x i32]* %stack, i32 0, i32 %tmp0
-  store i32 4, i32* %arrayidx1, align 4
-  %arrayidx2 = getelementptr inbounds i32, i32 addrspace(1)* %in, i32 1
-  %tmp1 = load i32, i32 addrspace(1)* %arrayidx2, align 4
-  %arrayidx3 = getelementptr inbounds [5 x i32], [5 x i32]* %stack, i32 0, i32 %tmp1
-  store i32 5, i32* %arrayidx3, align 4
-  %arrayidx4 = getelementptr inbounds [5 x i32], [5 x i32]* %stack, i32 0, i32 0
-  %tmp2 = load i32, i32* %arrayidx4, align 4
-  store i32 %tmp2, i32 addrspace(1)* %out, align 4
-  %arrayidx5 = getelementptr inbounds [5 x i32], [5 x i32]* %stack, i32 0, i32 1
-  %tmp3 = load i32, i32* %arrayidx5
-  %arrayidx6 = getelementptr inbounds i32, i32 addrspace(1)* %out, i32 1
-  store i32 %tmp3, i32 addrspace(1)* %arrayidx6
-  ret void
-}
-
-attributes #0 = { nounwind "amdgpu-max-work-group-size"="64" }