From: Cameron Zwarich <zwarich@apple.com>
Date: Tue, 1 Mar 2011 21:13:53 +0000 (+0000)
Subject: Stop computing the number of uses twice per value in CodeGenPrepare's sinking of
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=4c078f0d6df6136cbbcf581c254869051d455fdc;p=oota-llvm.git

Stop computing the number of uses twice per value in CodeGenPrepare's sinking of
addressing code. On 403.gcc this almost halves CodeGenPrepare time and reduces
total llc time by 9.5%. Unfortunately, getNumUses() is still the hottest function
in llc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126782 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Scalar/CodeGenPrepare.cpp b/lib/Transforms/Scalar/CodeGenPrepare.cpp
index 9536939ba2d..5d17e5f8d52 100644
--- a/lib/Transforms/Scalar/CodeGenPrepare.cpp
+++ b/lib/Transforms/Scalar/CodeGenPrepare.cpp
@@ -701,7 +701,7 @@ bool CodeGenPrepare::OptimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
   // the addressing mode obtained from the non-PHI roots of the graph
   // are equivalent.
   Value *Consensus = 0;
-  unsigned NumUses = 0;
+  unsigned NumUsesConsensus = 0;
   SmallVector<Instruction*, 16> AddrModeInsts;
   ExtAddrMode AddrMode;
   while (!worklist.empty()) {
@@ -734,9 +734,10 @@ bool CodeGenPrepare::OptimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
     // such root as representative, select the one with the most uses in order
     // to keep the cost modeling heuristics in AddressingModeMatcher applicable.
     if (!Consensus || NewAddrMode == AddrMode) {
-      if (V->getNumUses() > NumUses) {
+      unsigned NumUses = V->getNumUses();
+      if (NumUses > NumUsesConsensus) {
         Consensus = V;
-        NumUses = V->getNumUses();
+        NumUsesConsensus = NumUses;
         AddrMode = NewAddrMode;
         AddrModeInsts = NewAddrModeInsts;
       }