[llvm] [CodeGen] Do not emit TRAP for `unreachable` after `@llvm.trap` (PR #94570)

[Matt Arsenault via llvm-commits]

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@@ -1836,6 +1837,16 @@ class CallInst : public CallBase {
   bool canReturnTwice() const { return hasFnAttr(Attribute::ReturnsTwice); }
   void setCanReturnTwice() { addFnAttr(Attribute::ReturnsTwice); }
 
+  bool isNonContinuableTrap() const {
+    switch (getIntrinsicID()) {
+    case Intrinsic::trap:
+    case Intrinsic::ubsantrap:
+      return !hasFnAttr("trap-func-name");
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arsenm wrote:

It's not obvious to me why this attribute matters. Could this just be any noreturn intrinsic? 

https://github.com/llvm/llvm-project/pull/94570