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[SimplifyLibCalls] Fix instruction misplacement in string/memory libcall optimization

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When trying to optimize fortified library functions use the right
location to insert new instructions in order to preserve correct
def-use order.

This fixes an issue where a misplaced instruction definition would
happen to be *after* one of its use after a RAUW, forming invalid IR.
This behavior was introduced by r227250.

Differential Revision: http://reviews.llvm.org/D13301

rdar://problem/22802369

llvm-svn: 249092
This commit is contained in:
Bruno Cardoso Lopes 2015-10-01 22:43:53 +00:00
parent 27753ff832
commit f80e20287d
2 changed files with 32 additions and 2 deletions
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8
lib/Transforms/Utils/SimplifyLibCalls.cpp
View File

@ -2075,13 +2075,17 @@ Value *LibCallSimplifier::optimizeCall(CallInst *CI) {
if (Value *SimplifiedFortifiedCI = FortifiedSimplifier.optimizeCall(CI)) {
// Try to further simplify the result.
CallInst *SimplifiedCI = dyn_cast<CallInst>(SimplifiedFortifiedCI);
if (SimplifiedCI && SimplifiedCI->getCalledFunction())
if (Value *V = optimizeStringMemoryLibCall(SimplifiedCI, Builder)) {
if (SimplifiedCI && SimplifiedCI->getCalledFunction()) {
// Use an IR Builder from SimplifiedCI if available instead of CI
// to guarantee we reach all uses we might replace later on.
IRBuilder<> TmpBuilder(SimplifiedCI);
if (Value *V = optimizeStringMemoryLibCall(SimplifiedCI, TmpBuilder)) {
// If we were able to further simplify, remove the now redundant call.
SimplifiedCI->replaceAllUsesWith(V);
SimplifiedCI->eraseFromParent();
return V;
}
}
return SimplifiedFortifiedCI;
}

26
test/Transforms/InstCombine/memset_chk-1.ll
View File

@ -63,4 +63,30 @@ define i8* @test_no_simplify2() {
ret i8* %ret
}
; Test that RAUW in SimplifyLibCalls for __memset_chk generates valid IR
define i32 @test_rauw(i8* %a, i8* %b, i8** %c) {
; CHECK-LABEL: test_rauw
entry:
%call49 = call i64 @strlen(i8* %a)
%add180 = add i64 %call49, 1
%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
%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
%call185 = call i8* @__memset_chk(i8* %call51i, i32 0, i64 %add52.i.i, i64 -1)
ret i32 4
}
declare i8* @__memmove_chk(i8*, i8*, i64, i64)
declare i8* @strrchr(i8*, i32)
declare i64 @strlen(i8* nocapture)
declare i64 @llvm.objectsize.i64.p0i8(i8*, i1)
declare i8* @__memset_chk(i8*, i32, i64, i64)