[llvm-commits] [llvm] r150863 - in /llvm/trunk: lib/Analysis/InstructionSimplify.cpp test/Transforms/InstSimplify/compare.ll

[Eli Friedman]

Author: efriedma
Date: Fri Feb 17 21:29:25 2012
New Revision: 150863

URL: http://llvm.org/viewvc/llvm-project?rev=150863&view=rev
Log:
Fix a rather nasty regression from r150690: LHS != RHS does not imply LHS->stripPointerCasts() != RHS->stripPointerCasts().


Modified:
    llvm/trunk/lib/Analysis/InstructionSimplify.cpp
    llvm/trunk/test/Transforms/InstSimplify/compare.ll

Modified: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=150863&r1=150862&r2=150863&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/InstructionSimplify.cpp (original)
+++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp Fri Feb 17 21:29:25 2012
@@ -1593,10 +1593,11 @@
   // the compare, and if only one of them is then we moved it to RHS already.
   Value *LHSPtr = LHS->stripPointerCasts();
   Value *RHSPtr = RHS->stripPointerCasts();
+  if (LHSPtr == RHSPtr)
+    return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
   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));
 
   // If we are comparing with zero then try hard since this is a common case.

Modified: llvm/trunk/test/Transforms/InstSimplify/compare.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/compare.ll?rev=150863&r1=150862&r2=150863&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/compare.ll (original)
+++ llvm/trunk/test/Transforms/InstSimplify/compare.ll Fri Feb 17 21:29:25 2012
@@ -30,6 +30,16 @@
 ; CHECK-NEXT: ret i1 false
 }
 
+define i1 @gep2() {
+; CHECK: @gep2
+  %a = alloca [3 x i8], align 8
+  %x = getelementptr inbounds [3 x i8]* %a, i32 0, i32 0
+  %y = getelementptr inbounds [3 x i8]* %a, i32 0, i32 0
+  %cmp = icmp eq i8* %x, %y
+  ret i1 %cmp
+; CHECK-NEXT: ret i1 true
+}
+
 define i1 @zext(i32 %x) {
 ; CHECK: @zext
   %e1 = zext i32 %x to i64