From a96fc2f3ad3b31ffb605c0ace86fcd53260fb903 Mon Sep 17 00:00:00 2001
From: David Greene <greened@obbligato.org>
Date: Fri, 20 Nov 2009 21:13:27 +0000
Subject: Cleanups.

Make things a little more efficient as suggested by Evan.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89489 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/RegAllocLinearScan.cpp | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

(limited to 'lib/CodeGen/RegAllocLinearScan.cpp')

diff --git a/lib/CodeGen/RegAllocLinearScan.cpp b/lib/CodeGen/RegAllocLinearScan.cpp
index 708ecbe..4ff5129 100644
--- a/lib/CodeGen/RegAllocLinearScan.cpp
+++ b/lib/CodeGen/RegAllocLinearScan.cpp
@@ -87,6 +87,7 @@ namespace {
       // Initialize the queue to record recently-used registers.
       if (NumRecentlyUsedRegs > 0)
         RecentRegs.resize(NumRecentlyUsedRegs, 0);
+      RecentNext = RecentRegs.begin();
     }
 
     typedef std::pair<LiveInterval*, LiveInterval::iterator> IntervalPtr;
@@ -154,14 +155,16 @@ namespace {
     std::auto_ptr<Spiller> spiller_;
 
     // The queue of recently-used registers.
-    SmallVector<unsigned, 3> RecentRegs;
+    SmallVector<unsigned, 4> RecentRegs;
+    SmallVector<unsigned, 4>::iterator RecentNext;
 
     // Record that we just picked this register.
     void recordRecentlyUsed(unsigned reg) {
       assert(reg != 0 && "Recently used register is NOREG!");
       if (!RecentRegs.empty()) {
-        std::copy(RecentRegs.begin() + 1, RecentRegs.end(), RecentRegs.begin());
-        RecentRegs.back() = reg;
+        *RecentNext++ = reg;
+        if (RecentNext == RecentRegs.end())
+          RecentNext = RecentRegs.begin();
       }
     }
 
-- 
cgit v1.1