[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 {
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arsenm wrote:

Needs documentation comment. Also wouldn't any "trap" be "noncontinuable"? Can this just be isTrapIntrinsic? 

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