[llvm] 15488ff - [CodeGen] Fix the computation of the alignment of split stores.
Clement Courbet via llvm-commits
llvm-commits at lists.llvm.org
Wed Feb 12 01:37:47 PST 2020
Author: Clement Courbet
Date: 2020-02-12T10:37:30+01:00
New Revision: 15488ff24b4ae205f979be7248b38655acd82f9c
URL: https://github.com/llvm/llvm-project/commit/15488ff24b4ae205f979be7248b38655acd82f9c
DIFF: https://github.com/llvm/llvm-project/commit/15488ff24b4ae205f979be7248b38655acd82f9c.diff
LOG: [CodeGen] Fix the computation of the alignment of split stores.
Summary:
Right now the alignment of the lower half of a store is computed as
align/2, which fails for unaligned stores (align = 1), and is overly
pessimitic for, e.g. a 8 byte store aligned to 4 bytes.
Fixes PR44851
Fixes PR44877
Reviewers: gchatelet, spatel, lebedev.ri
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D74311
Added:
Modified:
llvm/lib/CodeGen/CodeGenPrepare.cpp
llvm/test/Transforms/CodeGenPrepare/PowerPC/split-store-alignment.ll
llvm/test/Transforms/CodeGenPrepare/X86/split-store-alignment.ll
Removed:
################################################################################
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index efcf7ba39009..ce758d698c96 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -6864,12 +6864,19 @@ static bool splitMergedValStore(StoreInst &SI, const DataLayout &DL,
Value *Addr = Builder.CreateBitCast(
SI.getOperand(1),
SplitStoreType->getPointerTo(SI.getPointerAddressSpace()));
- if ((IsLE && Upper) || (!IsLE && !Upper))
+ const bool IsOffsetStore = (IsLE && Upper) || (!IsLE && !Upper);
+ if (IsOffsetStore)
Addr = Builder.CreateGEP(
SplitStoreType, Addr,
ConstantInt::get(Type::getInt32Ty(SI.getContext()), 1));
- Builder.CreateAlignedStore(V, Addr,
- Upper ? SI.getAlign() / 2 : SI.getAlign());
+ MaybeAlign Alignment = SI.getAlign();
+ if (IsOffsetStore && Alignment) {
+ // When splitting the store in half, naturally one half will retain the
+ // alignment of the original wider store, regardless of whether it was
+ // over-aligned or not, while the other will require adjustment.
+ Alignment = commonAlignment(Alignment, HalfValBitSize / 8);
+ }
+ Builder.CreateAlignedStore(V, Addr, Alignment);
};
CreateSplitStore(LValue, false);
diff --git a/llvm/test/Transforms/CodeGenPrepare/PowerPC/split-store-alignment.ll b/llvm/test/Transforms/CodeGenPrepare/PowerPC/split-store-alignment.ll
index 53cf743ef02d..5bc7d3a3b3b4 100644
--- a/llvm/test/Transforms/CodeGenPrepare/PowerPC/split-store-alignment.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/PowerPC/split-store-alignment.ll
@@ -2,6 +2,42 @@
; RUN: opt -S -codegenprepare -mtriple=powerpc64-unknown-linux-gnu -data-layout="E-m:e-i64:64-n32:64" -force-split-store < %s | FileCheck --check-prefixes=ALL,BE %s
; RUN: opt -S -codegenprepare -mtriple=powerpc64le-unknown-linux-gnu -data-layout="e-m:e-i64:64-n32:64" -force-split-store < %s | FileCheck --check-prefixes=ALL,LE %s
+define void @split_store_align1(float %x, i64* %p) {
+; BE-LABEL: @split_store_align1(
+; BE-NEXT: [[B:%.*]] = bitcast float [[X:%.*]] to i32
+; BE-NEXT: [[Z:%.*]] = zext i32 0 to i64
+; BE-NEXT: [[S:%.*]] = shl nuw nsw i64 [[Z]], 32
+; BE-NEXT: [[Z2:%.*]] = zext i32 [[B]] to i64
+; BE-NEXT: [[O:%.*]] = or i64 [[S]], [[Z2]]
+; BE-NEXT: [[TMP1:%.*]] = bitcast i64* [[P:%.*]] to i32*
+; BE-NEXT: [[TMP2:%.*]] = getelementptr i32, i32* [[TMP1]], i32 1
+; BE-NEXT: store i32 [[B]], i32* [[TMP2]], align 1
+; BE-NEXT: [[TMP3:%.*]] = bitcast i64* [[P]] to i32*
+; BE-NEXT: store i32 0, i32* [[TMP3]], align 1
+; BE-NEXT: ret void
+;
+; LE-LABEL: @split_store_align1(
+; LE-NEXT: [[B:%.*]] = bitcast float [[X:%.*]] to i32
+; LE-NEXT: [[Z:%.*]] = zext i32 0 to i64
+; LE-NEXT: [[S:%.*]] = shl nuw nsw i64 [[Z]], 32
+; LE-NEXT: [[Z2:%.*]] = zext i32 [[B]] to i64
+; LE-NEXT: [[O:%.*]] = or i64 [[S]], [[Z2]]
+; LE-NEXT: [[TMP1:%.*]] = bitcast i64* [[P:%.*]] to i32*
+; LE-NEXT: store i32 [[B]], i32* [[TMP1]], align 1
+; LE-NEXT: [[TMP2:%.*]] = bitcast i64* [[P]] to i32*
+; LE-NEXT: [[TMP3:%.*]] = getelementptr i32, i32* [[TMP2]], i32 1
+; LE-NEXT: store i32 0, i32* [[TMP3]], align 1
+; LE-NEXT: ret void
+;
+ %b = bitcast float %x to i32
+ %z = zext i32 0 to i64
+ %s = shl nuw nsw i64 %z, 32
+ %z2 = zext i32 %b to i64
+ %o = or i64 %s, %z2
+ store i64 %o, i64* %p, align 1
+ ret void
+}
+
define void @split_store_align2(float %x, i64* %p) {
; BE-LABEL: @split_store_align2(
; BE-NEXT: [[B:%.*]] = bitcast float [[X:%.*]] to i32
@@ -13,7 +49,7 @@ define void @split_store_align2(float %x, i64* %p) {
; BE-NEXT: [[TMP2:%.*]] = getelementptr i32, i32* [[TMP1]], i32 1
; BE-NEXT: store i32 [[B]], i32* [[TMP2]], align 2
; BE-NEXT: [[TMP3:%.*]] = bitcast i64* [[P]] to i32*
-; BE-NEXT: store i32 0, i32* [[TMP3]], align 1
+; BE-NEXT: store i32 0, i32* [[TMP3]], align 2
; BE-NEXT: ret void
;
; LE-LABEL: @split_store_align2(
@@ -26,7 +62,7 @@ define void @split_store_align2(float %x, i64* %p) {
; LE-NEXT: store i32 [[B]], i32* [[TMP1]], align 2
; LE-NEXT: [[TMP2:%.*]] = bitcast i64* [[P]] to i32*
; LE-NEXT: [[TMP3:%.*]] = getelementptr i32, i32* [[TMP2]], i32 1
-; LE-NEXT: store i32 0, i32* [[TMP3]], align 1
+; LE-NEXT: store i32 0, i32* [[TMP3]], align 2
; LE-NEXT: ret void
;
%b = bitcast float %x to i32
@@ -47,9 +83,9 @@ define void @split_store_align8(float %x, i64* %p) {
; BE-NEXT: [[O:%.*]] = or i64 [[S]], [[Z2]]
; BE-NEXT: [[TMP1:%.*]] = bitcast i64* [[P:%.*]] to i32*
; BE-NEXT: [[TMP2:%.*]] = getelementptr i32, i32* [[TMP1]], i32 1
-; BE-NEXT: store i32 [[B]], i32* [[TMP2]], align 8
+; BE-NEXT: store i32 [[B]], i32* [[TMP2]], align 4
; BE-NEXT: [[TMP3:%.*]] = bitcast i64* [[P]] to i32*
-; BE-NEXT: store i32 0, i32* [[TMP3]], align 4
+; BE-NEXT: store i32 0, i32* [[TMP3]], align 8
; BE-NEXT: ret void
;
; LE-LABEL: @split_store_align8(
diff --git a/llvm/test/Transforms/CodeGenPrepare/X86/split-store-alignment.ll b/llvm/test/Transforms/CodeGenPrepare/X86/split-store-alignment.ll
index 7e0f5125f087..7eb8cb8ebfe1 100644
--- a/llvm/test/Transforms/CodeGenPrepare/X86/split-store-alignment.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/X86/split-store-alignment.ll
@@ -4,6 +4,29 @@
target datalayout = "e-m:x-p:32:32-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:32-n8:16:32-a:0:32-S32"
target triple = "i686-w64-windows-gnu"
+define void @split_store_align1(float %x, i64* %p) {
+; CHECK-LABEL: @split_store_align1(
+; CHECK-NEXT: [[B:%.*]] = bitcast float [[X:%.*]] to i32
+; CHECK-NEXT: [[Z:%.*]] = zext i32 0 to i64
+; CHECK-NEXT: [[S:%.*]] = shl nuw nsw i64 [[Z]], 32
+; CHECK-NEXT: [[Z2:%.*]] = zext i32 [[B]] to i64
+; CHECK-NEXT: [[O:%.*]] = or i64 [[S]], [[Z2]]
+; CHECK-NEXT: [[TMP1:%.*]] = bitcast i64* [[P:%.*]] to i32*
+; CHECK-NEXT: store i32 [[B]], i32* [[TMP1]], align 1
+; CHECK-NEXT: [[TMP2:%.*]] = bitcast i64* [[P]] to i32*
+; CHECK-NEXT: [[TMP3:%.*]] = getelementptr i32, i32* [[TMP2]], i32 1
+; CHECK-NEXT: store i32 0, i32* [[TMP3]], align 1
+; CHECK-NEXT: ret void
+;
+ %b = bitcast float %x to i32
+ %z = zext i32 0 to i64
+ %s = shl nuw nsw i64 %z, 32
+ %z2 = zext i32 %b to i64
+ %o = or i64 %s, %z2
+ store i64 %o, i64* %p, align 1
+ ret void
+}
+
define void @split_store_align2(float %x, i64* %p) {
; CHECK-LABEL: @split_store_align2(
; CHECK-NEXT: [[B:%.*]] = bitcast float [[X:%.*]] to i32
@@ -15,7 +38,7 @@ define void @split_store_align2(float %x, i64* %p) {
; CHECK-NEXT: store i32 [[B]], i32* [[TMP1]], align 2
; CHECK-NEXT: [[TMP2:%.*]] = bitcast i64* [[P]] to i32*
; CHECK-NEXT: [[TMP3:%.*]] = getelementptr i32, i32* [[TMP2]], i32 1
-; CHECK-NEXT: store i32 0, i32* [[TMP3]], align 1
+; CHECK-NEXT: store i32 0, i32* [[TMP3]], align 2
; CHECK-NEXT: ret void
;
%b = bitcast float %x to i32
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