[llvm] [SCEVExpander] Don't try to reuse SCEVUnknown values (PR #115141)

[Nikita Popov via llvm-commits]

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@@ -14,12 +14,14 @@ define i8 @widget(ptr %arr, i8 %t9) {
 ; CHECK-NEXT:    br i1 [[C]], label [[FOR_PREHEADER:%.*]], label [[BB6]]
 ; CHECK:       for.preheader:
 ; CHECK-NEXT:    [[T1_0_LCSSA:%.*]] = phi ptr [ [[T1_0]], [[BB6]] ]
+; CHECK-NEXT:    [[T1_0_LCSSA4:%.*]] = phi ptr [ [[T1_0]], [[BB6]] ]
+; CHECK-NEXT:    [[T1_0_LCSSA1:%.*]] = phi ptr [ [[T1_0]], [[BB6]] ]
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nikic wrote:

Downside is that we might generate more LCSSA phis, but this seems like an independent SCEVExpander problem.

https://github.com/llvm/llvm-project/pull/115141