[llvm-commits] [llvm] r89489 - /llvm/trunk/lib/CodeGen/RegAllocLinearScan.cpp

[David Greene]

Author: greened
Date: Fri Nov 20 15:13:27 2009
New Revision: 89489

URL: http://llvm.org/viewvc/llvm-project?rev=89489&view=rev
Log:

Cleanups.

Make things a little more efficient as suggested by Evan.

Modified:
    llvm/trunk/lib/CodeGen/RegAllocLinearScan.cpp

Modified: llvm/trunk/lib/CodeGen/RegAllocLinearScan.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegAllocLinearScan.cpp?rev=89489&r1=89488&r2=89489&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/RegAllocLinearScan.cpp (original)
+++ llvm/trunk/lib/CodeGen/RegAllocLinearScan.cpp Fri Nov 20 15:13:27 2009
@@ -87,6 +87,7 @@
       // 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 @@
     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();
       }
     }