[llvm] [VPlan] Handle ExplicitVectorLength in opcodeMayReadOrWriteFromMemory (PR #167647)

[Luke Lau via llvm-commits]

https://github.com/lukel97 created https://github.com/llvm/llvm-project/pull/167647

This has no effect for now from what I can tell but is needed if we ever want to extend narrowInterleaveGroups to handle EVL tail folded loops.
diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index 80cd112dbcd8..488470d24796 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -1259,6 +1259,7 @@ bool VPInstruction::opcodeMayReadOrWriteFromMemory() const {
   case VPInstruction::ExtractLastLanePerPart:
   case VPInstruction::ExtractPenultimateElement:
   case VPInstruction::ActiveLaneMask:
+  case VPInstruction::ExplicitVectorLength:
   case VPInstruction::FirstActiveLane:
   case VPInstruction::FirstOrderRecurrenceSplice:
   case VPInstruction::LogicalAnd:


>From f8a80b12ddaea0a47577edc163f68f9f7dc94b3e Mon Sep 17 00:00:00 2001
From: Luke Lau <luke at igalia.com>
Date: Wed, 12 Nov 2025 14:57:18 +0800
Subject: [PATCH] [VPlan] Handle ExplicitVectorLength in
 opcodeMayReadOrWriteFromMemory

This has no effect for now from what I can tell but is needed if we ever want to extend narrowInterleaveGroups to handle EVL tail folded loops.
diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index 80cd112dbcd8..488470d24796 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -1259,6 +1259,7 @@ bool VPInstruction::opcodeMayReadOrWriteFromMemory() const {
   case VPInstruction::ExtractLastLanePerPart:
   case VPInstruction::ExtractPenultimateElement:
   case VPInstruction::ActiveLaneMask:
+  case VPInstruction::ExplicitVectorLength:
   case VPInstruction::FirstActiveLane:
   case VPInstruction::FirstOrderRecurrenceSplice:
   case VPInstruction::LogicalAnd:
---
 llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index 80cd112dbcd8a..488470d247968 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -1259,6 +1259,7 @@ bool VPInstruction::opcodeMayReadOrWriteFromMemory() const {
   case VPInstruction::ExtractLastLanePerPart:
   case VPInstruction::ExtractPenultimateElement:
   case VPInstruction::ActiveLaneMask:
+  case VPInstruction::ExplicitVectorLength:
   case VPInstruction::FirstActiveLane:
   case VPInstruction::FirstOrderRecurrenceSplice:
   case VPInstruction::LogicalAnd: