InstSimplify: Ignore pointer casts when constant folding compares between pointers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150690 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp
index 7656220..9d5b74c 100644
--- a/lib/Analysis/InstructionSimplify.cpp
+++ b/lib/Analysis/InstructionSimplify.cpp
@@ -1591,8 +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));
diff --git a/test/Transforms/InstSimplify/compare.ll b/test/Transforms/InstSimplify/compare.ll
index 0c4153f..60f5990 100644
--- a/test/Transforms/InstSimplify/compare.ll
+++ b/test/Transforms/InstSimplify/compare.ll
@@ -10,6 +10,26 @@
; CHECK: ret i1 false
}
+define i1 @bitcast() {
+; CHECK: @bitcast
+ %a = alloca i32
+ %b = alloca i64
+ %x = bitcast i32* %a to i8*
+ %y = bitcast i64* %b to i8*
+ %cmp = icmp eq i8* %x, %y
+ ret i1 %cmp
+; CHECK-NEXT: ret i1 false
+}
+
+define i1 @gep() {
+; CHECK: @gep
+ %a = alloca [3 x i8], align 8
+ %x = getelementptr inbounds [3 x i8]* %a, i32 0, i32 0
+ %cmp = icmp eq i8* %x, null
+ ret i1 %cmp
+; CHECK-NEXT: ret i1 false
+}
+
define i1 @zext(i32 %x) {
; CHECK: @zext
%e1 = zext i32 %x to i64