From b491a2d641add36f1a2f7674d6b5df038c2d638e Mon Sep 17 00:00:00 2001 From: Bruno Cardoso Lopes Date: Thu, 1 Oct 2015 22:43:53 +0000 Subject: [SimplifyLibCalls] Fix instruction misplacement in string/memory libcall optimization 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 --- llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp') diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp index 763e3c05a9d..d5d802ded56 100644 --- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp @@ -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(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; } -- cgit v1.2.3