[LV] Strengthen assert: VPlan0 doesn't have WidenPHIs (NFC)

[artagnon]

VPWidenCanonicalIV and VPBlend recipes are created by VPPredicator, and VPCanonicalIVPHI and VPInstruction recipes are created by VPlanConstruction. WidenPHIs are never created.

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

@llvm/pr-subscribers-vectorizers

Author: Ramkumar Ramachandra (artagnon)

Changes

VPWidenCanonicalIV and VPBlend recipes are created by VPPredicator, and VPCanonicalIVPHI and VPInstruction recipes are created by VPlanConstruction. WidenPHIs are never created.

---

Full diff: https://github.com/llvm/llvm-project/pull/165715.diff

1 Files Affected:

• (modified) llvm/lib/Transforms/Vectorize/LoopVectorize.cpp (+1-5)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index f7968abbe5b6b..a8a57c8ac8239 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -8335,11 +8335,7 @@ VPlanPtr LoopVectorizationPlanner::tryToBuildVPlanWithVPRecipes(
               &R) ||
           (isa<VPInstruction>(&R) && !UnderlyingValue))
         continue;
-
-      // FIXME: VPlan0, which models a copy of the original scalar loop, should
-      // not use VPWidenPHIRecipe to model the phis.
-      assert((isa<VPWidenPHIRecipe>(&R) || isa<VPInstruction>(&R)) &&
-             UnderlyingValue && "unsupported recipe");
+      assert(isa<VPInstruction>(&R) && UnderlyingValue && "unsupported recipe");
 
       // TODO: Gradually replace uses of underlying instruction by analyses on
       // VPlan.

[fhahn]

LGTM, thanks