[llvm] [SCCP] Support constant structure in PhiNode (PR #163713)

[Nikita Popov via llvm-commits]

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@@ -2125,6 +2143,21 @@ void SCCPInstVisitor::handleCallResult(CallBase &CB) {
   }
 }
 
+bool SCCPInstVisitor::isInstOverDefined(Instruction &Inst) {
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nikic wrote:

```suggestion
bool SCCPInstVisitor::isInstFullyOverDefined(Instruction &Inst) {
```
Maybe? To make it clearer that this only returns true if all the elements are overdefined.

https://github.com/llvm/llvm-project/pull/163713