[llvm-commits] [llvm] r150695 - /llvm/trunk/lib/Analysis/InstructionSimplify.cpp
Benjamin Kramer
benny.kra at googlemail.com
Thu Feb 16 07:19:59 PST 2012
Author: d0k
Date: Thu Feb 16 09:19:59 2012
New Revision: 150695
URL: http://llvm.org/viewvc/llvm-project?rev=150695&view=rev
Log:
Revert "InstSimplify: Strip pointer casts early."
Turns out this isn't safe, because the code below depends on LHS and RHS having
the same type.
Modified:
llvm/trunk/lib/Analysis/InstructionSimplify.cpp
Modified: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=150695&r1=150694&r2=150695&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/InstructionSimplify.cpp (original)
+++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp Thu Feb 16 09:19:59 2012
@@ -1542,10 +1542,6 @@
Type *ITy = GetCompareTy(LHS); // The return type.
Type *OpTy = LHS->getType(); // The operand type.
- // Remove pointer casts that don't change the value.
- LHS = LHS->stripPointerCasts();
- RHS = RHS->stripPointerCasts();
-
// icmp X, X -> true/false
// X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
// because X could be 0.
@@ -1595,8 +1591,11 @@
// to the case where LHS is a global variable address or null is pointless,
// since if both LHS and RHS are constants then we already constant folded
// the compare, and if only one of them is then we moved it to RHS already.
- if (isa<AllocaInst>(LHS) && (isa<GlobalValue>(RHS) || isa<AllocaInst>(RHS) ||
- isa<ConstantPointerNull>(RHS)))
+ Value *LHSPtr = LHS->stripPointerCasts();
+ Value *RHSPtr = RHS->stripPointerCasts();
+ if (isa<AllocaInst>(LHSPtr) && (isa<GlobalValue>(RHSPtr) ||
+ isa<AllocaInst>(RHSPtr) ||
+ isa<ConstantPointerNull>(RHSPtr)))
// We already know that LHS != RHS.
return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
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