1 files changed, 34 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index fd38738..c55c40c 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -839,6 +839,35 @@ InstCombinerImpl::foldIntrinsicWithOverflowCommon(IntrinsicInst *II) {
   if (OptimizeOverflowCheck(WO->getBinaryOp(), WO->isSigned(), WO->getLHS(),
                             WO->getRHS(), *WO, OperationResult, OverflowResult))
     return createOverflowTuple(WO, OperationResult, OverflowResult);
+
+  // See whether we can optimize the overflow check with assumption information.
+  for (User *U : WO->users()) {
+    if (!match(U, m_ExtractValue<1>(m_Value())))
+      continue;
+
+    for (auto &AssumeVH : AC.assumptionsFor(U)) {
+      if (!AssumeVH)
+        continue;
+      CallInst *I = cast<CallInst>(AssumeVH);
+      if (!match(I->getArgOperand(0), m_Not(m_Specific(U))))
+        continue;
+      if (!isValidAssumeForContext(I, II, /*DT=*/nullptr,
+                                   /*AllowEphemerals=*/true))
+        continue;
+      Value *Result =
+          Builder.CreateBinOp(WO->getBinaryOp(), WO->getLHS(), WO->getRHS());
+      Result->takeName(WO);
+      if (auto *Inst = dyn_cast<Instruction>(Result)) {
+        if (WO->isSigned())
+          Inst->setHasNoSignedWrap();
+        else
+          Inst->setHasNoUnsignedWrap();
+      }
+      return createOverflowTuple(WO, Result,
+                                 ConstantInt::getFalse(U->getType()));
+    }
+  }
+
   return nullptr;
 }
 
@@ -2644,8 +2673,11 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
     // Propagate sign argument through nested calls:
     // copysign Mag, (copysign ?, X) --> copysign Mag, X
     Value *X;
-    if (match(Sign, m_Intrinsic<Intrinsic::copysign>(m_Value(), m_Value(X))))
-      return replaceOperand(*II, 1, X);
+    if (match(Sign, m_Intrinsic<Intrinsic::copysign>(m_Value(), m_Value(X)))) {
+      Value *CopySign =
+          Builder.CreateCopySign(Mag, X, FMFSource::intersect(II, Sign));
+      return replaceInstUsesWith(*II, CopySign);
+    }
 
     // Clear sign-bit of constant magnitude:
     // copysign -MagC, X --> copysign MagC, X