[llvm] [AArch64] Don't run loop-idiom-vectorize pass in the O0 pipeline (PR #156802)

[Fangrui Song via llvm-commits]

https://github.com/MaskRay created https://github.com/llvm/llvm-project/pull/156802

As noted in 156787


>From f6181ec619752de5403176d33ae9159aba649a97 Mon Sep 17 00:00:00 2001
From: Fangrui Song <i at maskray.me>
Date: Wed, 3 Sep 2025 21:49:42 -0700
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
 =?UTF-8?q?l=20version?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Created using spr 1.3.5-bogner
---
 llvm/lib/Target/AArch64/AArch64TargetMachine.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Target/AArch64/AArch64TargetMachine.cpp b/llvm/lib/Target/AArch64/AArch64TargetMachine.cpp
index e67bd5869ccd1..4650b2d0c8151 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetMachine.cpp
+++ b/llvm/lib/Target/AArch64/AArch64TargetMachine.cpp
@@ -589,7 +589,8 @@ void AArch64TargetMachine::registerPassBuilderCallbacks(PassBuilder &PB) {
 
   PB.registerLateLoopOptimizationsEPCallback(
       [=](LoopPassManager &LPM, OptimizationLevel Level) {
-        LPM.addPass(LoopIdiomVectorizePass());
+        if (Level != OptimizationLevel::O0)
+          LPM.addPass(LoopIdiomVectorizePass());
       });
   if (getTargetTriple().isOSWindows())
     PB.registerPipelineEarlySimplificationEPCallback(