From: Chandler Carruth <chandlerc@gmail.com>
Date: Thu, 5 Jul 2012 12:40:45 +0000 (+0000)
Subject: Optimize extendIntervalEndTo a tiny bit by saving one call through the
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=95c88b8cb210ffad127519a143fade685ab21f5b;p=oota-llvm.git

Optimize extendIntervalEndTo a tiny bit by saving one call through the
vector erase. No functionality changed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159746 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/LiveInterval.cpp b/lib/CodeGen/LiveInterval.cpp
index 8990360a721..3d34c089b9f 100644
--- a/lib/CodeGen/LiveInterval.cpp
+++ b/lib/CodeGen/LiveInterval.cpp
@@ -196,16 +196,16 @@ void LiveInterval::extendIntervalEndTo(Ranges::iterator I, SlotIndex NewEnd) {
   // If NewEnd was in the middle of an interval, make sure to get its endpoint.
   I->end = std::max(NewEnd, prior(MergeTo)->end);
 
-  // Erase any dead ranges.
-  ranges.erase(llvm::next(I), MergeTo);
-
   // If the newly formed range now touches the range after it and if they have
   // the same value number, merge the two ranges into one range.
-  Ranges::iterator Next = llvm::next(I);
-  if (Next != ranges.end() && Next->start <= I->end && Next->valno == ValNo) {
-    I->end = Next->end;
-    ranges.erase(Next);
+  if (MergeTo != ranges.end() && MergeTo->start <= I->end &&
+      MergeTo->valno == ValNo) {
+    I->end = MergeTo->end;
+    ++MergeTo;
   }
+
+  // Erase any dead ranges.
+  ranges.erase(llvm::next(I), MergeTo);
 }