[llvm] r281110 - LSV: Fix incorrectly increasing alignment
Matt Arsenault via llvm-commits
llvm-commits at lists.llvm.org
Fri Sep 9 15:20:14 PDT 2016
Author: arsenm
Date: Fri Sep 9 17:20:14 2016
New Revision: 281110
URL: http://llvm.org/viewvc/llvm-project?rev=281110&view=rev
Log:
LSV: Fix incorrectly increasing alignment
If the unaligned access has a dynamic offset, it may be odd which
would make the adjusted alignment incorrect to use.
Added:
llvm/trunk/test/Transforms/LoadStoreVectorizer/AMDGPU/adjust-alloca-alignment.ll
Modified:
llvm/trunk/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
Modified: llvm/trunk/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp?rev=281110&r1=281109&r2=281110&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp Fri Sep 9 17:20:14 2016
@@ -31,6 +31,7 @@
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Vectorize.h"
using namespace llvm;
@@ -742,7 +743,8 @@ bool Vectorizer::vectorizeStoreChain(
// Store size should be 1B, 2B or multiple of 4B.
// TODO: Target hook for size constraint?
- unsigned SzInBytes = (Sz / 8) * ChainSize;
+ unsigned EltSzInBytes = Sz / 8;
+ unsigned SzInBytes = EltSzInBytes * ChainSize;
if (SzInBytes > 2 && SzInBytes % 4 != 0) {
DEBUG(dbgs() << "LSV: Size should be 1B, 2B "
"or multiple of 4B. Splitting.\n");
@@ -790,15 +792,11 @@ bool Vectorizer::vectorizeStoreChain(
if (S0->getPointerAddressSpace() != 0)
return false;
- // If we're storing to an object on the stack, we control its alignment,
- // so we can cheat and change it!
- Value *V = GetUnderlyingObject(S0->getPointerOperand(), DL);
- if (AllocaInst *AI = dyn_cast_or_null<AllocaInst>(V)) {
- AI->setAlignment(StackAdjustedAlignment);
- Alignment = StackAdjustedAlignment;
- } else {
+ unsigned NewAlign = getOrEnforceKnownAlignment(S0->getPointerOperand(),
+ StackAdjustedAlignment,
+ DL, S0, nullptr, &DT);
+ if (NewAlign < StackAdjustedAlignment)
return false;
- }
}
BasicBlock::iterator First, Last;
@@ -899,7 +897,8 @@ bool Vectorizer::vectorizeLoadChain(
// Load size should be 1B, 2B or multiple of 4B.
// TODO: Should size constraint be a target hook?
- unsigned SzInBytes = (Sz / 8) * ChainSize;
+ unsigned EltSzInBytes = Sz / 8;
+ unsigned SzInBytes = EltSzInBytes * ChainSize;
if (SzInBytes > 2 && SzInBytes % 4 != 0) {
DEBUG(dbgs() << "LSV: Size should be 1B, 2B "
"or multiple of 4B. Splitting.\n");
@@ -940,15 +939,13 @@ bool Vectorizer::vectorizeLoadChain(
if (L0->getPointerAddressSpace() != 0)
return false;
- // If we're loading from an object on the stack, we control its alignment,
- // so we can cheat and change it!
- Value *V = GetUnderlyingObject(L0->getPointerOperand(), DL);
- if (AllocaInst *AI = dyn_cast_or_null<AllocaInst>(V)) {
- AI->setAlignment(StackAdjustedAlignment);
- Alignment = StackAdjustedAlignment;
- } else {
+ unsigned NewAlign = getOrEnforceKnownAlignment(L0->getPointerOperand(),
+ StackAdjustedAlignment,
+ DL, L0, nullptr, &DT);
+ if (NewAlign < StackAdjustedAlignment)
return false;
- }
+
+ Alignment = NewAlign;
}
DEBUG({
@@ -1029,6 +1026,7 @@ bool Vectorizer::accessIsMisaligned(unsi
unsigned Alignment) {
if (Alignment % SzInBytes == 0)
return false;
+
bool Fast = false;
bool Allows = TTI.allowsMisalignedMemoryAccesses(F.getParent()->getContext(),
SzInBytes * 8, AddressSpace,
Added: llvm/trunk/test/Transforms/LoadStoreVectorizer/AMDGPU/adjust-alloca-alignment.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoadStoreVectorizer/AMDGPU/adjust-alloca-alignment.ll?rev=281110&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/LoadStoreVectorizer/AMDGPU/adjust-alloca-alignment.ll (added)
+++ llvm/trunk/test/Transforms/LoadStoreVectorizer/AMDGPU/adjust-alloca-alignment.ll Fri Sep 9 17:20:14 2016
@@ -0,0 +1,129 @@
+; RUN: opt -S -load-store-vectorizer -mattr=-unaligned-buffer-access,+max-private-element-size-16 < %s | FileCheck -check-prefix=ALIGNED -check-prefix=ALL %s
+; RUN: opt -S -load-store-vectorizer -mattr=+unaligned-buffer-access,+max-private-element-size-16 < %s | FileCheck -check-prefix=UNALIGNED -check-prefix=ALL %s
+
+target datalayout = "e-p:32:32-p1:64:64-p2:64:64-p3:32:32-p4:64:64-p5:32:32-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64"
+target triple = "amdgcn--"
+
+; ALL-LABEL: @load_unknown_offset_align1_i8(
+; ALL: alloca [128 x i8], align 1
+; UNALIGNED: load <2 x i8>, <2 x i8>* %{{[0-9]+}}, align 1{{$}}
+
+; ALIGNED: load i8, i8* %ptr0, align 1{{$}}
+; ALIGNED: load i8, i8* %ptr1, align 1{{$}}
+define void @load_unknown_offset_align1_i8(i8 addrspace(1)* noalias %out, i32 %offset) #0 {
+ %alloca = alloca [128 x i8], align 1
+ %ptr0 = getelementptr inbounds [128 x i8], [128 x i8]* %alloca, i32 0, i32 %offset
+ %val0 = load i8, i8* %ptr0, align 1
+ %ptr1 = getelementptr inbounds i8, i8* %ptr0, i32 1
+ %val1 = load i8, i8* %ptr1, align 1
+ %add = add i8 %val0, %val1
+ store i8 %add, i8 addrspace(1)* %out
+ ret void
+}
+
+; ALL-LABEL: @load_unknown_offset_align1_i16(
+; ALL: alloca [128 x i16], align 1{{$}}
+; UNALIGNED: load <2 x i16>, <2 x i16>* %{{[0-9]+}}, align 1{{$}}
+
+; ALIGNED: load i16, i16* %ptr0, align 1{{$}}
+; ALIGNED: load i16, i16* %ptr1, align 1{{$}}
+define void @load_unknown_offset_align1_i16(i16 addrspace(1)* noalias %out, i32 %offset) #0 {
+ %alloca = alloca [128 x i16], align 1
+ %ptr0 = getelementptr inbounds [128 x i16], [128 x i16]* %alloca, i32 0, i32 %offset
+ %val0 = load i16, i16* %ptr0, align 1
+ %ptr1 = getelementptr inbounds i16, i16* %ptr0, i32 1
+ %val1 = load i16, i16* %ptr1, align 1
+ %add = add i16 %val0, %val1
+ store i16 %add, i16 addrspace(1)* %out
+ ret void
+}
+
+; FIXME: Although the offset is unknown here, we know it is a multiple
+; of the element size, so should still be align 4
+
+; ALL-LABEL: @load_unknown_offset_align1_i32(
+; ALL: alloca [128 x i32], align 1
+; UNALIGNED: load <2 x i32>, <2 x i32>* %{{[0-9]+}}, align 1{{$}}
+
+; ALIGNED: load i32, i32* %ptr0, align 1
+; ALIGNED: load i32, i32* %ptr1, align 1
+define void @load_unknown_offset_align1_i32(i32 addrspace(1)* noalias %out, i32 %offset) #0 {
+ %alloca = alloca [128 x i32], align 1
+ %ptr0 = getelementptr inbounds [128 x i32], [128 x i32]* %alloca, i32 0, i32 %offset
+ %val0 = load i32, i32* %ptr0, align 1
+ %ptr1 = getelementptr inbounds i32, i32* %ptr0, i32 1
+ %val1 = load i32, i32* %ptr1, align 1
+ %add = add i32 %val0, %val1
+ store i32 %add, i32 addrspace(1)* %out
+ ret void
+}
+
+; FIXME: Should always increase alignment of the load
+; Make sure alloca alignment isn't decreased
+; ALL-LABEL: @load_alloca16_unknown_offset_align1_i32(
+; ALL: alloca [128 x i32], align 16
+
+; UNALIGNED: load <2 x i32>, <2 x i32>* %{{[0-9]+}}, align 1{{$}}
+; ALIGNED: load <2 x i32>, <2 x i32>* %{{[0-9]+}}, align 4{{$}}
+define void @load_alloca16_unknown_offset_align1_i32(i32 addrspace(1)* noalias %out, i32 %offset) #0 {
+ %alloca = alloca [128 x i32], align 16
+ %ptr0 = getelementptr inbounds [128 x i32], [128 x i32]* %alloca, i32 0, i32 %offset
+ %val0 = load i32, i32* %ptr0, align 1
+ %ptr1 = getelementptr inbounds i32, i32* %ptr0, i32 1
+ %val1 = load i32, i32* %ptr1, align 1
+ %add = add i32 %val0, %val1
+ store i32 %add, i32 addrspace(1)* %out
+ ret void
+}
+
+; ALL-LABEL: @store_unknown_offset_align1_i8(
+; ALL: alloca [128 x i8], align 1
+; UNALIGNED: store <2 x i8> <i8 9, i8 10>, <2 x i8>* %{{[0-9]+}}, align 1{{$}}
+
+; ALIGNED: store i8 9, i8* %ptr0, align 1{{$}}
+; ALIGNED: store i8 10, i8* %ptr1, align 1{{$}}
+define void @store_unknown_offset_align1_i8(i8 addrspace(1)* noalias %out, i32 %offset) #0 {
+ %alloca = alloca [128 x i8], align 1
+ %ptr0 = getelementptr inbounds [128 x i8], [128 x i8]* %alloca, i32 0, i32 %offset
+ store i8 9, i8* %ptr0, align 1
+ %ptr1 = getelementptr inbounds i8, i8* %ptr0, i32 1
+ store i8 10, i8* %ptr1, align 1
+ ret void
+}
+
+; ALL-LABEL: @store_unknown_offset_align1_i16(
+; ALL: alloca [128 x i16], align 1
+; UNALIGNED: store <2 x i16> <i16 9, i16 10>, <2 x i16>* %{{[0-9]+}}, align 1{{$}}
+
+; ALIGNED: store i16 9, i16* %ptr0, align 1{{$}}
+; ALIGNED: store i16 10, i16* %ptr1, align 1{{$}}
+define void @store_unknown_offset_align1_i16(i16 addrspace(1)* noalias %out, i32 %offset) #0 {
+ %alloca = alloca [128 x i16], align 1
+ %ptr0 = getelementptr inbounds [128 x i16], [128 x i16]* %alloca, i32 0, i32 %offset
+ store i16 9, i16* %ptr0, align 1
+ %ptr1 = getelementptr inbounds i16, i16* %ptr0, i32 1
+ store i16 10, i16* %ptr1, align 1
+ ret void
+}
+
+; FIXME: Although the offset is unknown here, we know it is a multiple
+; of the element size, so it still should be align 4.
+
+; ALL-LABEL: @store_unknown_offset_align1_i32(
+; ALL: alloca [128 x i32], align 1
+
+; UNALIGNED: store <2 x i32> <i32 9, i32 10>, <2 x i32>* %{{[0-9]+}}, align 1{{$}}
+
+; ALIGNED: store i32 9, i32* %ptr0, align 1
+; ALIGNED: store i32 10, i32* %ptr1, align 1
+define void @store_unknown_offset_align1_i32(i32 addrspace(1)* noalias %out, i32 %offset) #0 {
+ %alloca = alloca [128 x i32], align 1
+ %ptr0 = getelementptr inbounds [128 x i32], [128 x i32]* %alloca, i32 0, i32 %offset
+ store i32 9, i32* %ptr0, align 1
+ %ptr1 = getelementptr inbounds i32, i32* %ptr0, i32 1
+ store i32 10, i32* %ptr1, align 1
+ ret void
+}
+
+attributes #0 = { nounwind }
+
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