From cc4c43f648a8021c7dc410a090559e9733fc0bbb Mon Sep 17 00:00:00 2001 From: Nick Lewycky Date: Mon, 24 Oct 2011 04:35:36 +0000 Subject: A dead malloc, a free(NULL) and a free(undef) are all trivially dead instructions. This doesn't introduce any optimizations we weren't doing before (except potentially due to pass ordering issues), now passes will eliminate them sooner as part of their own cleanups. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142787 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Utils/Local.cpp | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'lib/Transforms/Utils/Local.cpp') diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp index 7034feb227..134ab71050 100644 --- a/lib/Transforms/Utils/Local.cpp +++ b/lib/Transforms/Utils/Local.cpp @@ -28,6 +28,7 @@ #include "llvm/Analysis/DIBuilder.h" #include "llvm/Analysis/Dominators.h" #include "llvm/Analysis/InstructionSimplify.h" +#include "llvm/Analysis/MemoryBuiltins.h" #include "llvm/Analysis/ProfileInfo.h" #include "llvm/Analysis/ValueTracking.h" #include "llvm/Target/TargetData.h" @@ -257,6 +258,13 @@ bool llvm::isInstructionTriviallyDead(Instruction *I) { II->getIntrinsicID() == Intrinsic::lifetime_end) return isa(II->getArgOperand(1)); } + + if (extractMallocCall(I)) return true; + + if (CallInst *CI = isFreeCall(I)) + if (Constant *C = dyn_cast(CI->getArgOperand(0))) + return C->isNullValue() || isa(C); + return false; } -- cgit v1.2.3