[PATCH] D50841: [TableGen] TypeSetByHwMode::operator== optimization
Simon Pilgrim via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Thu Aug 16 07:11:02 PDT 2018
RKSimon created this revision.
RKSimon added reviewers: sdardis, kparzysz, zturner, rengolin, MatzeB, fhahn.
This operator is called a great deal, by checking for the cheap isSimple equality cases first (a common occurrence) we can improve performance as we avoid a lot of std::map find/iteration in hasDefault.
isSimple also means that a default value is present, so we can avoid some hasDefault calls.
This also avoids a rather dodgy piece of logic that was checking for isSimple() && !VTS.isSimple() but not the inverse - it now uses the general hasDefault mode comparison test instead.
Saves around 15secs in debug builds of x86 -gen-dag-isel.
Repository:
rL LLVM
https://reviews.llvm.org/D50841
Files:
utils/TableGen/CodeGenDAGPatterns.cpp
Index: utils/TableGen/CodeGenDAGPatterns.cpp
===================================================================
--- utils/TableGen/CodeGenDAGPatterns.cpp
+++ utils/TableGen/CodeGenDAGPatterns.cpp
@@ -198,16 +198,18 @@
}
bool TypeSetByHwMode::operator==(const TypeSetByHwMode &VTS) const {
- bool HaveDefault = hasDefault();
- if (HaveDefault != VTS.hasDefault())
+ // The isSimple call is much quicker than hasDefault - check this first.
+ bool IsSimple = isSimple();
+ bool VTSIsSimple = VTS.isSimple();
+ if (IsSimple && VTSIsSimple)
+ return *begin() == *VTS.begin();
+
+ // Speedup: We have a default if the set is simple.
+ bool HaveDefault = IsSimple || hasDefault();
+ bool VTSHaveDefault = VTSIsSimple || VTS.hasDefault();
+ if (HaveDefault != VTSHaveDefault)
return false;
- if (isSimple()) {
- if (VTS.isSimple())
- return *begin() == *VTS.begin();
- return false;
- }
-
SmallDenseSet<unsigned, 4> Modes;
for (auto &I : *this)
Modes.insert(I.first);
-------------- next part --------------
A non-text attachment was scrubbed...
Name: D50841.161024.patch
Type: text/x-patch
Size: 1035 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20180816/d3be15af/attachment.bin>
More information about the llvm-commits
mailing list