From: Evgeny Stupachenko <evstupac@gmail.com>
Date: Wed, 30 Nov 2016 22:23:51 +0000 (+0000)
Subject: Fix LSR best register search algorithm.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=e18cb89a650d9e151b0090c9abd17a87b0bce9c3;p=llvm

Fix LSR best register search algorithm.

Summary:
Fix a case when first register in a search has maximum
RegUses.getUsedByIndices(Reg).count()

Reviewers: qcolombet

Differential Revision: http://reviews.llvm.org/D26877

From: Evgeny Stupachenko <evstupac@gmail.com>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288278 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 2a378a43728..a61f646042a 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -4178,9 +4178,10 @@ void LSRInstance::NarrowSearchSpaceByPickingWinnerRegs() {
     for (const SCEV *Reg : RegUses) {
       if (Taken.count(Reg))
         continue;
-      if (!Best)
+      if (!Best) {
         Best = Reg;
-      else {
+        BestNum = RegUses.getUsedByIndices(Reg).count();
+      } else {
         unsigned Count = RegUses.getUsedByIndices(Reg).count();
         if (Count > BestNum) {
           Best = Reg;