[PATCH] D46085: AMDGPU/SI: Don't promote alloca to vector for atomic load/store

[Changpeng Fang via Phabricator via llvm-commits]

cfang created this revision.
cfang added reviewers: arsenm, msearles.
Herald added subscribers: t-tye, tpr, dstuttard, yaxunl, nhaehnle, wdng, kzhuravl.

Don't promote alloca to vector for atomic load/store


https://reviews.llvm.org/D46085

Files:
  lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp
  test/CodeGen/AMDGPU/vector-alloca-atomic.ll


Index: test/CodeGen/AMDGPU/vector-alloca-atomic.ll
===================================================================
--- /dev/null
+++ test/CodeGen/AMDGPU/vector-alloca-atomic.ll
@@ -0,0 +1,67 @@
+; RUN: opt -S -mtriple=amdgcn---amdgiz -amdgpu-promote-alloca -sroa -instcombine < %s | FileCheck -check-prefix=OPT %s
+target datalayout = "A5"
+
+
+; Show that what the alloca promotion pass will do for non-atomic load/store.
+
+; OPT-LABEL: @vector_alloca_not_atomic(
+;
+; OPT: extractelement <3 x i32> <i32 0, i32 1, i32 2>, i64 %index
+define amdgpu_kernel void @vector_alloca_not_atomic(i32 addrspace(1)* %out, i64 %index) {
+entry:
+  %alloca = alloca [3 x i32], addrspace(5)
+  %a0 = getelementptr [3 x i32], [3 x i32] addrspace(5)* %alloca, i32 0, i32 0
+  %a1 = getelementptr [3 x i32], [3 x i32] addrspace(5)* %alloca, i32 0, i32 1
+  %a2 = getelementptr [3 x i32], [3 x i32] addrspace(5)* %alloca, i32 0, i32 2
+  store i32 0, i32 addrspace(5)* %a0
+  store i32 1, i32 addrspace(5)* %a1
+  store i32 2, i32 addrspace(5)* %a2
+  %tmp = getelementptr [3 x i32], [3 x i32] addrspace(5)* %alloca, i64 0, i64 %index
+  %data = load i32, i32 addrspace(5)* %tmp
+  store i32 %data, i32 addrspace(1)* %out
+  ret void
+}
+
+; OPT-LABEL: @vector_alloca_atomic_read(
+;
+; OPT: alloca [3 x i32]
+; OPT: store i32 0
+; OPT: store i32 1
+; OPT: store i32 2
+; OPT: load atomic i32
+define amdgpu_kernel void @vector_alloca_atomic_read(i32 addrspace(1)* %out, i64 %index) {
+entry:
+  %alloca = alloca [3 x i32], addrspace(5)
+  %a0 = getelementptr [3 x i32], [3 x i32] addrspace(5)* %alloca, i32 0, i32 0
+  %a1 = getelementptr [3 x i32], [3 x i32] addrspace(5)* %alloca, i32 0, i32 1
+  %a2 = getelementptr [3 x i32], [3 x i32] addrspace(5)* %alloca, i32 0, i32 2
+  store i32 0, i32 addrspace(5)* %a0
+  store i32 1, i32 addrspace(5)* %a1
+  store i32 2, i32 addrspace(5)* %a2
+  %tmp = getelementptr [3 x i32], [3 x i32] addrspace(5)* %alloca, i64 0, i64 %index
+  %data = load atomic i32, i32 addrspace(5)* %tmp acquire, align 4
+  store i32 %data, i32 addrspace(1)* %out
+  ret void
+}
+
+; OPT-LABEL: @vector_alloca_atomic_srite(
+;
+; OPT: alloca [3 x i32]
+; OPT: store atomic i32 0
+; OPT: store atomic i32 1
+; OPT: store atomic i32 2
+; OPT: load i32
+define amdgpu_kernel void @vector_alloca_atomic_write(i32 addrspace(1)* %out, i64 %index) {
+entry:
+  %alloca = alloca [3 x i32], addrspace(5)
+  %a0 = getelementptr [3 x i32], [3 x i32] addrspace(5)* %alloca, i32 0, i32 0
+  %a1 = getelementptr [3 x i32], [3 x i32] addrspace(5)* %alloca, i32 0, i32 1
+  %a2 = getelementptr [3 x i32], [3 x i32] addrspace(5)* %alloca, i32 0, i32 2
+  store atomic i32 0, i32 addrspace(5)* %a0 release, align 4
+  store atomic i32 1, i32 addrspace(5)* %a1 release, align 4
+  store atomic i32 2, i32 addrspace(5)* %a2  release, align 4
+  %tmp = getelementptr [3 x i32], [3 x i32] addrspace(5)* %alloca, i64 0, i64 %index
+  %data = load i32, i32 addrspace(5)* %tmp
+  store i32 %data, i32 addrspace(1)* %out
+  ret void
+}
Index: lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp
===================================================================
--- lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp
+++ lib/Target/AMDGPU/AMDGPUPromoteAlloca.cpp
@@ -324,6 +324,8 @@
   switch (Inst->getOpcode()) {
   case Instruction::Load: {
     LoadInst *LI = cast<LoadInst>(Inst);
+    if (LI->getOrdering() != AtomicOrdering::NotAtomic)
+      return false;
     // Currently only handle the case where the Pointer Operand is a GEP so check for that case.
     return isa<GetElementPtrInst>(LI->getPointerOperand()) && !LI->isVolatile();
   }
@@ -334,6 +336,8 @@
     // Must be the stored pointer operand, not a stored value, plus
     // since it should be canonical form, the User should be a GEP.
     StoreInst *SI = cast<StoreInst>(Inst);
+    if (SI->getOrdering() != AtomicOrdering::NotAtomic)
+      return false;
     return (SI->getPointerOperand() == User) && isa<GetElementPtrInst>(User) && !SI->isVolatile();
   }
   default:


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