1 files changed, 9 insertions, 3 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index e80d6a9ee39..ed0e1c90888 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -1462,11 +1462,17 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) {
   if (Value *V = SimplifyUsingDistributiveLaws(I))
     return ReplaceInstUsesWith(I, V);
 
-  // If this is a 'B = x-(-A)', change to B = x+A.  This preserves NSW/NUW.
+  // If this is a 'B = x-(-A)', change to B = x+A.
   if (Value *V = dyn_castNegVal(Op1)) {
     BinaryOperator *Res = BinaryOperator::CreateAdd(Op0, V);
-    Res->setHasNoSignedWrap(I.hasNoSignedWrap());
-    Res->setHasNoUnsignedWrap(I.hasNoUnsignedWrap());
+
+    if (const auto *BO = dyn_cast<BinaryOperator>(Op1)) {
+      assert(BO->getOpcode() == Instruction::Sub &&
+             "Expected a subtraction operator!");
+      if (BO->hasNoSignedWrap() && I.hasNoSignedWrap())
+        Res->setHasNoSignedWrap(true);
+    }
+
     return Res;
   }