[compiler-rt] [llvm] [flang] [clang] [clang-tools-extra] [VPlan] Replace VPRecipeOrVPValue with VP2VP recipe simplification. (PR #76090)

[Florian Hahn via llvm-commits]

================
@@ -8292,13 +8271,13 @@ VPRecipeOrVPValueTy VPRecipeBuilder::tryToBlend(PHINode *Phi,
   for (unsigned In = 0; In < NumIncoming; In++) {
     VPValue *EdgeMask =
         createEdgeMask(Phi->getIncomingBlock(In), Phi->getParent(), *Plan);
-    assert((EdgeMask || NumIncoming == 1) &&
+    assert((EdgeMask || NumIncoming == 1 || Operands[In] == Operands[0]) &&
----------------
fhahn wrote:

There can be degenerate cases like

```
loop.1.header:
  %iv.1 = phi i32 [ 0, %entry ], [ %iv.1.next, %loop.1.latch ]
  %l = load i32, ptr %A
  br i1 %c, label %loop.1.latch, label %loop.1.latch

loop.1.latch:
  %p = phi i32 [ %l, %loop.1.header ], [ %l, %loop.1.header ]
  %iv.1.next = add nuw nsw i32 %iv.1, 1
  %ec.1 = icmp eq i32 %iv.1.next, 100
  br i1 %ec.1, label %exit.1, label %loop.1.header
```

https://github.com/llvm/llvm-project/pull/76090