[llvm] [CodeGen] Avoid generating trap instructions after exception restore intrinsics (PR #109560)

[Matt Arsenault via llvm-commits]

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@@ -3125,6 +3125,14 @@ bool IRTranslator::translateUnreachable(const User &U, MachineIRBuilder &MIRBuil
     // Do not emit an additional trap instruction.
     if (Call->isNonContinuableTrap())
       return true;
+    // Do not emit trap instructions after EH_RETURN intrinsics.
+    // This can cause problems later down the line when other machine passes
+    // attempt to use the last instruction in a BB to determine terminator behavior.
+    if (const auto *II = dyn_cast<IntrinsicInst>(Call)) {
+      const auto IID = II->getIntrinsicID();
+      if (IID == Intrinsic::eh_return_i32 || IID == Intrinsic::eh_return_i64)
+        return true;
+    }
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arsenm wrote:

These intrinsics are missing from the langref and I don't know what's expected of them. Should these really be terminators in the first place? Can the insert point just be adjusted? 

> use the last instruction in a BB to determine terminator behavior.

This comment doesn't exactly make sense 

https://github.com/llvm/llvm-project/pull/109560