[llvm] r259674 - [InstCombine] Revert r238452: Fold IntToPtr and PtrToInt into preceding loads.
Quentin Colombet via llvm-commits
llvm-commits at lists.llvm.org
Wed Feb 3 10:04:13 PST 2016
Author: qcolombet
Date: Wed Feb 3 12:04:13 2016
New Revision: 259674
URL: http://llvm.org/viewvc/llvm-project?rev=259674&view=rev
Log:
[InstCombine] Revert r238452: Fold IntToPtr and PtrToInt into preceding loads.
According to git bisect, this is the root cause of a miscompile for Regex in
libLLVMSupport. I am still working on reducing a test case.
The actual bug may be elsewhere and this commit just exposed it.
Anyway, at the moment, to reproduce, follow these steps:
1. Build clang and libLTO in release mode.
2. Create a new build directory <stage2> and cd into it.
3. Use clang and libLTO from #1 to build llvm-extract in Release mode + asserts
using -O2 -flto
4. Run llvm-extract -ralias '.*bar' -S test/Other/extract-alias.ll
Result:
program doesn't contain global named '.*bar'!
Expected result:
@a0a0bar = alias void ()* @bar
@a0bar = alias void ()* @bar
declare void @bar()
Note: In step #3, if you don't use lto or asserts, the miscompile disappears.
Removed:
llvm/trunk/test/Transforms/InstCombine/load-bitcast32.ll
llvm/trunk/test/Transforms/InstCombine/load-bitcast64.ll
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
llvm/trunk/test/Transforms/InstCombine/memset_chk-1.ll
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp?rev=259674&r1=259673&r2=259674&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp Wed Feb 3 12:04:13 2016
@@ -495,17 +495,12 @@ static Instruction *combineLoadToOperati
}
// Fold away bit casts of the loaded value by loading the desired type.
- // We can do this for BitCastInsts as well as casts from and to pointer types,
- // as long as those are noops (i.e., the source or dest type have the same
- // bitwidth as the target's pointers).
if (LI.hasOneUse())
- if (auto* CI = dyn_cast<CastInst>(LI.user_back())) {
- if (CI->isNoopCast(DL)) {
- LoadInst *NewLoad = combineLoadToNewType(IC, LI, CI->getDestTy());
- CI->replaceAllUsesWith(NewLoad);
- IC.eraseInstFromFunction(*CI);
- return &LI;
- }
+ if (auto *BC = dyn_cast<BitCastInst>(LI.user_back())) {
+ LoadInst *NewLoad = combineLoadToNewType(IC, LI, BC->getDestTy());
+ BC->replaceAllUsesWith(NewLoad);
+ IC.eraseInstFromFunction(*BC);
+ return &LI;
}
// FIXME: We should also canonicalize loads of vectors when their elements are
Removed: llvm/trunk/test/Transforms/InstCombine/load-bitcast32.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/load-bitcast32.ll?rev=259673&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/load-bitcast32.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/load-bitcast32.ll (removed)
@@ -1,79 +0,0 @@
-; RUN: opt -instcombine -S < %s | FileCheck %s
-
-target datalayout = "p:32:32:32"
-
-
-define i64* @test1(i8* %x) {
-entry:
-; CHECK-LABEL: @test1(
-; CHECK: load i64, i64*
-; CHECK: ret
- %a = bitcast i8* %x to i64*
- %b = load i64, i64* %a
- %c = inttoptr i64 %b to i64*
-
- ret i64* %c
-}
-
-define i32* @test2(i8* %x) {
-entry:
-; CHECK-LABEL: @test2(
-; CHECK: load i32*, i32**
-; CHECK: ret
- %a = bitcast i8* %x to i32*
- %b = load i32, i32* %a
- %c = inttoptr i32 %b to i32*
-
- ret i32* %c
-}
-
-define i64* @test3(i8* %x) {
-entry:
-; CHECK-LABEL: @test3(
-; CHECK: load i64*, i64**
-; CHECK: ret
- %a = bitcast i8* %x to i32*
- %b = load i32, i32* %a
- %c = inttoptr i32 %b to i64*
-
- ret i64* %c
-}
-
-define i64 @test4(i8* %x) {
-entry:
-; CHECK-LABEL: @test4(
-; CHECK: load i32, i32*
-; CHECK: zext
-; CHECK: ret
- %a = bitcast i8* %x to i64**
- %b = load i64*, i64** %a
- %c = ptrtoint i64* %b to i64
-
- ret i64 %c
-}
-
-define i32 @test5(i8* %x) {
-entry:
-; CHECK-LABEL: @test5(
-; CHECK: load i32, i32*
-; CHECK: ret
- %a = bitcast i8* %x to i32**
- %b = load i32*, i32** %a
- %c = ptrtoint i32* %b to i32
-
- ret i32 %c
-}
-
-define i64 @test6(i8* %x) {
-entry:
-; CHECK-LABEL: @test6(
-; CHECK: load i32, i32*
-; CHECK: zext
-; CHECK: ret
- %a = bitcast i8* %x to i32**
- %b = load i32*, i32** %a
- %c = ptrtoint i32* %b to i64
-
- ret i64 %c
-}
-
Removed: llvm/trunk/test/Transforms/InstCombine/load-bitcast64.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/load-bitcast64.ll?rev=259673&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/load-bitcast64.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/load-bitcast64.ll (removed)
@@ -1,78 +0,0 @@
-; RUN: opt -instcombine -S < %s | FileCheck %s
-
-target datalayout = "p:64:64:64"
-
-
-define i64* @test1(i8* %x) {
-entry:
-; CHECK-LABEL: @test1(
-; CHECK: load i64*, i64**
-; CHECK: ret
- %a = bitcast i8* %x to i64*
- %b = load i64, i64* %a
- %c = inttoptr i64 %b to i64*
-
- ret i64* %c
-}
-
-define i32* @test2(i8* %x) {
-entry:
-; CHECK-LABEL: @test2(
-; CHECK: load i32, i32*
-; CHECK: ret
- %a = bitcast i8* %x to i32*
- %b = load i32, i32* %a
- %c = inttoptr i32 %b to i32*
-
- ret i32* %c
-}
-
-define i64* @test3(i8* %x) {
-entry:
-; CHECK-LABEL: @test3(
-; CHECK: load i32, i32*
-; CHECK: ret
- %a = bitcast i8* %x to i32*
- %b = load i32, i32* %a
- %c = inttoptr i32 %b to i64*
-
- ret i64* %c
-}
-
-define i64 @test4(i8* %x) {
-entry:
-; CHECK-LABEL: @test4(
-; CHECK: load i64, i64*
-; CHECK: ret
- %a = bitcast i8* %x to i64**
- %b = load i64*, i64** %a
- %c = ptrtoint i64* %b to i64
-
- ret i64 %c
-}
-
-define i32 @test5(i8* %x) {
-entry:
-; CHECK-LABEL: @test5(
-; CHECK: load i64, i64*
-; CHECK: trunc
-; CHECK: ret
- %a = bitcast i8* %x to i32**
- %b = load i32*, i32** %a
- %c = ptrtoint i32* %b to i32
-
- ret i32 %c
-}
-
-define i64 @test6(i8* %x) {
-entry:
-; CHECK-LABEL: @test6(
-; CHECK: load i64, i64*
-; CHECK: ret
- %a = bitcast i8* %x to i32**
- %b = load i32*, i32** %a
- %c = ptrtoint i32* %b to i64
-
- ret i64 %c
-}
-
Modified: llvm/trunk/test/Transforms/InstCombine/memset_chk-1.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/memset_chk-1.ll?rev=259674&r1=259673&r2=259674&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/memset_chk-1.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/memset_chk-1.ll Wed Feb 3 12:04:13 2016
@@ -72,14 +72,14 @@ entry:
%yo107 = call i64 @llvm.objectsize.i64.p0i8(i8* %b, i1 false)
%call50 = call i8* @__memmove_chk(i8* %b, i8* %a, i64 %add180, i64 %yo107)
; CHECK: %strlen = call i64 @strlen(i8* %b)
-; CHECK-NEXT: %strchr2 = getelementptr i8, i8* %b, i64 %strlen
+; CHECK-NEXT: [[STRCHR:%[0-9a-zA-Z_-]+]] = getelementptr i8, i8* %b, i64 %strlen
%call51i = call i8* @strrchr(i8* %b, i32 0)
%d = load i8*, i8** %c, align 8
%sub182 = ptrtoint i8* %d to i64
%sub183 = ptrtoint i8* %b to i64
%sub184 = sub i64 %sub182, %sub183
%add52.i.i = add nsw i64 %sub184, 1
-; CHECK: call void @llvm.memset.p0i8.i64(i8* %strchr2
+; CHECK: call void @llvm.memset.p0i8.i64(i8* [[STRCHR]]
%call185 = call i8* @__memset_chk(i8* %call51i, i32 0, i64 %add52.i.i, i64 -1)
ret i32 4
}
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