PR9838: Fix transform introduced in r127064 to not trigger when only one side of the icmp is an exact shift.

llvm-svn: 130954

3 files changed, 13 insertions, 2 deletions

diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index e7ef6ffd8ad..22a64e1b348 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -1847,7 +1847,7 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
       // fall-through
     case Instruction::SDiv:
     case Instruction::AShr:
-      if (!LBO->isExact() && !RBO->isExact())
+      if (!LBO->isExact() || !RBO->isExact())
         break;
       if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
                                       RBO->getOperand(0), TD, DT, MaxRecurse-1))
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index bb9b88bfe6a..b6963c54999 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -2400,7 +2400,7 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
         // fall-through
       case Instruction::SDiv:
       case Instruction::AShr:
-        if (!BO0->isExact() && !BO1->isExact())
+        if (!BO0->isExact() || !BO1->isExact())
           break;
         return new ICmpInst(I.getPredicate(), BO0->getOperand(0),
                             BO1->getOperand(0));
diff --git a/llvm/test/Transforms/InstCombine/icmp.ll b/llvm/test/Transforms/InstCombine/icmp.ll
index 099540ac745..1237adee74d 100644
--- a/llvm/test/Transforms/InstCombine/icmp.ll
+++ b/llvm/test/Transforms/InstCombine/icmp.ll
@@ -510,3 +510,14 @@ define i1 @test52(i32 %x1) nounwind {
   ret i1 %A
 }
 
+; PR9838
+; CHECK: @test53
+; CHECK-NEXT: ashr exact
+; CHECK-NEXT: ashr
+; CHECK-NEXT: icmp
+define i1 @test53(i32 %a, i32 %b) nounwind {
+ %x = ashr exact i32 %a, 30
+ %y = ashr i32 %b, 30
+ %z = icmp eq i32 %x, %y
+ ret i1 %z
+}