[llvm] [LV] Strengthen assert: VPlan0 doesn't have WidenPHIs (NFC) (PR #165715)

[Ramkumar Ramachandra via llvm-commits]

https://github.com/artagnon created https://github.com/llvm/llvm-project/pull/165715

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

>From 8572fb73fefa95f589c87b27a3dfc52c2c49ec5f Mon Sep 17 00:00:00 2001
From: Ramkumar Ramachandra <ramkumar.ramachandra at codasip.com>
Date: Thu, 30 Oct 2025 12:35:52 +0000
Subject: [PATCH] [LV] Strengthen assert: VPlan0 doesn't have WidenPHIs (NFC)

VPWidenCanonicalIV and VPBlend recipes are created by VPPredicator, and
VPCanonicalIVPHI and VPInstruction recipes are created by
VPlanConstruction. WidenPHIs are never created.
---
 llvm/lib/Transforms/Vectorize/LoopVectorize.cpp | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

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.