[llvm-commits] [llvm] r127069 - /llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp
Cameron Zwarich
zwarich at apple.com
Sat Mar 5 00:12:26 PST 2011
Author: zwarich
Date: Sat Mar 5 02:12:26 2011
New Revision: 127069
URL: http://llvm.org/viewvc/llvm-project?rev=127069&view=rev
Log:
Fix PR9398 - 10% of llc compile time is spent in Value::getNumUses. This reduces
the percentage of time spent in CodeGenPrepare when llcing 403.gcc from 12.6% to
1.8% of total llc time.
Modified:
llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp?rev=127069&r1=127068&r2=127069&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp Sat Mar 5 02:12:26 2011
@@ -569,6 +569,7 @@
// are equivalent.
Value *Consensus = 0;
unsigned NumUsesConsensus = 0;
+ bool IsNumUsesConsensusValid = false;
SmallVector<Instruction*, 16> AddrModeInsts;
ExtAddrMode AddrMode;
while (!worklist.empty()) {
@@ -595,17 +596,31 @@
ExtAddrMode NewAddrMode =
AddressingModeMatcher::Match(V, AccessTy,MemoryInst,
NewAddrModeInsts, *TLI);
-
- // Ensure that the obtained addressing mode is equivalent to that obtained
- // for all other roots of the PHI traversal. Also, when choosing one
- // 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) {
+
+ // This check is broken into two cases with very similar code to avoid using
+ // getNumUses() as much as possible. Some values have a lot of uses, so
+ // calling getNumUses() unconditionally caused a significant compile-time
+ // regression.
+ if (!Consensus) {
+ Consensus = V;
+ AddrMode = NewAddrMode;
+ AddrModeInsts = NewAddrModeInsts;
+ continue;
+ } else if (NewAddrMode == AddrMode) {
+ if (!IsNumUsesConsensusValid) {
+ NumUsesConsensus = Consensus->getNumUses();
+ IsNumUsesConsensusValid = true;
+ }
+
+ // Ensure that the obtained addressing mode is equivalent to that obtained
+ // for all other roots of the PHI traversal. Also, when choosing one
+ // such root as representative, select the one with the most uses in order
+ // to keep the cost modeling heuristics in AddressingModeMatcher
+ // applicable.
unsigned NumUses = V->getNumUses();
if (NumUses > NumUsesConsensus) {
Consensus = V;
NumUsesConsensus = NumUses;
- AddrMode = NewAddrMode;
AddrModeInsts = NewAddrModeInsts;
}
continue;
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