diff options
Diffstat (limited to 'llvm/lib/CodeGen')
| -rw-r--r-- | llvm/lib/CodeGen/GlobalMerge.cpp | 26 |
1 files changed, 14 insertions, 12 deletions
diff --git a/llvm/lib/CodeGen/GlobalMerge.cpp b/llvm/lib/CodeGen/GlobalMerge.cpp index 41e01a1..7b76155 100644 --- a/llvm/lib/CodeGen/GlobalMerge.cpp +++ b/llvm/lib/CodeGen/GlobalMerge.cpp @@ -423,12 +423,24 @@ bool GlobalMergeImpl::doMerge(SmallVectorImpl<GlobalVariable *> &Globals, } } + // Now we found a bunch of sets of globals used together. We accumulated + // the number of times we encountered the sets (i.e., the number of functions + // that use that exact set of globals). + // + // Multiply that by the size of the set to give us a crude profitability + // metric. + llvm::stable_sort(UsedGlobalSets, + [](const UsedGlobalSet &UGS1, const UsedGlobalSet &UGS2) { + return UGS1.Globals.count() * UGS1.UsageCount < + UGS2.Globals.count() * UGS2.UsageCount; + }); + // We can choose to merge all globals together, but ignore globals never used // with another global. This catches the obviously non-profitable cases of // having a single global, but is aggressive enough for any other case. if (GlobalMergeIgnoreSingleUse) { BitVector AllGlobals(Globals.size()); - for (const UsedGlobalSet &UGS : UsedGlobalSets) { + for (const UsedGlobalSet &UGS : llvm::reverse(UsedGlobalSets)) { if (UGS.UsageCount == 0) continue; if (UGS.Globals.count() > 1) @@ -437,16 +449,6 @@ bool GlobalMergeImpl::doMerge(SmallVectorImpl<GlobalVariable *> &Globals, return doMerge(Globals, AllGlobals, M, isConst, AddrSpace); } - // Now we found a bunch of sets of globals used together. We accumulated - // the number of times we encountered the sets (i.e., the number of functions - // that use that exact set of globals). Multiply that by the size of the set - // to give us a crude profitability metric. - llvm::stable_sort(UsedGlobalSets, - [](const UsedGlobalSet &UGS1, const UsedGlobalSet &UGS2) { - return UGS1.Globals.count() * UGS1.UsageCount >= - UGS2.Globals.count() * UGS2.UsageCount; - }); - // Starting from the sets with the best (=biggest) profitability, find a // good combination. // The ideal (and expensive) solution can only be found by trying all @@ -456,7 +458,7 @@ bool GlobalMergeImpl::doMerge(SmallVectorImpl<GlobalVariable *> &Globals, BitVector PickedGlobals(Globals.size()); bool Changed = false; - for (const UsedGlobalSet &UGS : UsedGlobalSets) { + for (const UsedGlobalSet &UGS : llvm::reverse(UsedGlobalSets)) { if (UGS.UsageCount == 0) continue; if (PickedGlobals.anyCommon(UGS.Globals)) |