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author | Hans Wennborg <hans@hanshq.net> | 2012-11-16 20:14:40 +0000 |
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committer | Hans Wennborg <hans@hanshq.net> | 2012-11-16 20:14:40 +0000 |
commit | 21863332ca402263c518840742aee2b126d53007 (patch) | |
tree | 2a926d1196874c833de59bbb1edcdee70697d28b /lib/Transforms/IPO/GlobalOpt.cpp | |
parent | 3481efbe83bbd775b609ea02ee426fb956b9c43a (diff) | |
download | llvm-21863332ca402263c518840742aee2b126d53007.tar.gz llvm-21863332ca402263c518840742aee2b126d53007.tar.bz2 llvm-21863332ca402263c518840742aee2b126d53007.tar.xz |
Merge r168037 from trunk:
Make GlobalOpt be conservative with TLS variables (PR14309)
For global variables that get the same value stored into them
everywhere, GlobalOpt will replace them with a constant. The problem is
that a thread-local GlobalVariable looks like one value (the address of
the TLS var), but is different between threads.
This patch introduces Constant::isThreadDependent() which returns true
for thread-local variables and constants which depend on them (e.g. a GEP
into a thread-local array), and teaches GlobalOpt not to track such
values.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_32@168192 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/IPO/GlobalOpt.cpp')
-rw-r--r-- | lib/Transforms/IPO/GlobalOpt.cpp | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp index 678189b3d6..591278fa62 100644 --- a/lib/Transforms/IPO/GlobalOpt.cpp +++ b/lib/Transforms/IPO/GlobalOpt.cpp @@ -225,6 +225,7 @@ static bool AnalyzeGlobal(const Value *V, GlobalStatus &GS, // Don't hack on volatile stores. if (SI->isVolatile()) return true; + GS.Ordering = StrongerOrdering(GS.Ordering, SI->getOrdering()); // If this is a direct store to the global (i.e., the global is a scalar @@ -234,6 +235,14 @@ static bool AnalyzeGlobal(const Value *V, GlobalStatus &GS, if (const GlobalVariable *GV = dyn_cast<GlobalVariable>( SI->getOperand(1))) { Value *StoredVal = SI->getOperand(0); + + if (Constant *C = dyn_cast<Constant>(StoredVal)) { + if (C->isThreadDependent()) { + // The stored value changes between threads; don't track it. + return true; + } + } + if (StoredVal == GV->getInitializer()) { if (GS.StoredType < GlobalStatus::isInitializerStored) GS.StoredType = GlobalStatus::isInitializerStored; |