diff options
Diffstat (limited to 'lib/Transforms/IPO/ConstantMerge.cpp')
| -rw-r--r-- | lib/Transforms/IPO/ConstantMerge.cpp | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/lib/Transforms/IPO/ConstantMerge.cpp b/lib/Transforms/IPO/ConstantMerge.cpp index c3ecb7a..d8fae8a 100644 --- a/lib/Transforms/IPO/ConstantMerge.cpp +++ b/lib/Transforms/IPO/ConstantMerge.cpp @@ -140,18 +140,24 @@ bool ConstantMerge::runOnModule(Module &M) { UsedGlobals.count(GV)) continue; + // This transformation is legal for weak ODR globals in the sense it + // doesn't change semantics, but we really don't want to perform it + // anyway; it's likely to pessimize code generation, and some tools + // (like the Darwin linker in cases involving CFString) don't expect it. + if (GV->isWeakForLinker()) + continue; + Constant *Init = GV->getInitializer(); // Check to see if the initializer is already known. PointerIntPair<Constant*, 1, bool> Pair(Init, hasKnownAlignment(GV)); GlobalVariable *&Slot = CMap[Pair]; - // If this is the first constant we find or if the old on is local, - // replace with the current one. It the current is externally visible + // If this is the first constant we find or if the old one is local, + // replace with the current one. If the current is externally visible // it cannot be replace, but can be the canonical constant we merge with. - if (Slot == 0 || IsBetterCannonical(*GV, *Slot)) { + if (Slot == 0 || IsBetterCannonical(*GV, *Slot)) Slot = GV; - } } // Second: identify all globals that can be merged together, filling in |
