From 4fedc84270af2e8925439152e8c324487d01c8d7 Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper@intel.com>
Date: Fri, 3 Nov 2017 21:08:13 +0000
Subject: [PATCH] [SimplifyCFG] When merging conditional stores, don't count
the store we're merging against the PHINodeFoldingThreshold
Merging conditional stores tries to check to see if the code is if convertible after the store is moved. But the store hasn't been moved yet so its being counted against the threshold.
The patch adds 1 to the threshold comparison to make sure we don't count the store. I've adjusted a test to use a lower threshold to ensure we still do that conversion with the lower threshold.
Differential Revision: https://reviews.llvm.org/D39570
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317368 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/Transforms/Utils/SimplifyCFG.cpp | 4 +++-
test/Transforms/SimplifyCFG/merge-cond-stores-2.ll | 2 +-
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index 3c4dae92ebf..e0045e9f48a 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -2901,7 +2901,9 @@ static bool mergeConditionalStoreToAddress(BasicBlock *PTB, BasicBlock *PFB,
else
return false;
}
- return N <= PHINodeFoldingThreshold;
+ // The store we want to merge is counted in N, so add 1 to make sure
+ // we're counting the instructions that would be left.
+ return N <= (PHINodeFoldingThreshold + 1);
};
if (!MergeCondStoresAggressively &&
diff --git a/test/Transforms/SimplifyCFG/merge-cond-stores-2.ll b/test/Transforms/SimplifyCFG/merge-cond-stores-2.ll
index a2b94038001..a2ca63d0a2d 100644
--- a/test/Transforms/SimplifyCFG/merge-cond-stores-2.ll
+++ b/test/Transforms/SimplifyCFG/merge-cond-stores-2.ll
@@ -1,5 +1,5 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -S < %s -simplifycfg -simplifycfg-merge-cond-stores=true -simplifycfg-merge-cond-stores-aggressively=false -phi-node-folding-threshold=2 | FileCheck %s
+; RUN: opt -S < %s -simplifycfg -simplifycfg-merge-cond-stores=true -simplifycfg-merge-cond-stores-aggressively=false -phi-node-folding-threshold=1 | FileCheck %s
target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
target triple = "armv7--linux-gnueabihf"
--
2.40.0