[llvm] [VPlan] Only skip expansion for SCEVUnknown if it isn't an instruction. (PR #125235)

[Florian Hahn via llvm-commits]

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@@ -1451,7 +1451,7 @@ Value *SCEVExpander::expandCodeFor(const SCEV *SH, Type *Ty) {
   // Expand the code for this SCEV.
   Value *V = expand(SH);
 
-  if (Ty) {
+  if (Ty && Ty != V->getType()) {
     assert(SE.getTypeSizeInBits(Ty) == SE.getTypeSizeInBits(SH->getType()) &&
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fhahn wrote:

I *think* `expand` is guaranteed to return a value matching `SH`'s type. But in any case clarifying this would probably be best done separately, if needed.

https://github.com/llvm/llvm-project/pull/125235