[llvm] [IR] Add nowrap flags for trunc instruction (PR #85592)

[Matt Arsenault via llvm-commits]

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@@ -386,11 +394,17 @@ void Instruction::setNonNeg(bool b) {
 }
 
 bool Instruction::hasNoUnsignedWrap() const {
-  return cast<OverflowingBinaryOperator>(this)->hasNoUnsignedWrap();
+  if (auto Inst = cast<OverflowingBinaryOperator>(this))
+    return Inst->hasNoUnsignedWrap();
+
+  return cast<PossiblyNoWrapInst>(this)->hasNoUnsignedWrap();
 }
 
 bool Instruction::hasNoSignedWrap() const {
-  return cast<OverflowingBinaryOperator>(this)->hasNoSignedWrap();
+  if (auto Inst = cast<OverflowingBinaryOperator>(this))
+    return Inst->hasNoSignedWrap();
+
+  return cast<PossiblyNoWrapInst>(this)->hasNoSignedWrap();
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arsenm wrote:

Can there be a common base class for has nuw/nsw instead of requiring this split? 

https://github.com/llvm/llvm-project/pull/85592