Revert "[NFC] More ConstantMerge refactoring"
Sanitizers seem unhappy.
llvm-svn: 339480
diff --git a/llvm/lib/Transforms/IPO/ConstantMerge.cpp b/llvm/lib/Transforms/IPO/ConstantMerge.cpp
index 16a77c0..5ddf2e2 100644
--- a/llvm/lib/Transforms/IPO/ConstantMerge.cpp
+++ b/llvm/lib/Transforms/IPO/ConstantMerge.cpp
@@ -40,7 +40,7 @@
#define DEBUG_TYPE "constmerge"
-STATISTIC(NumIdenticalMerged, "Number of identical global constants merged");
+STATISTIC(NumMerged, "Number of global constants merged");
/// Find values that are marked as llvm.used.
static void FindUsedValues(GlobalVariable *LLVMUsed,
@@ -131,28 +131,25 @@
// Map unique constants to globals.
DenseMap<Constant *, GlobalVariable *> CMap;
- SmallVector<std::pair<GlobalVariable *, GlobalVariable *>, 32>
- SameContentReplacements;
+ // Replacements - This vector contains a list of replacements to perform.
+ SmallVector<std::pair<GlobalVariable*, GlobalVariable*>, 32> Replacements;
- size_t ChangesMade = 0;
- size_t OldChangesMade = 0;
+ bool MadeChange = false;
// Iterate constant merging while we are still making progress. Merging two
// constants together may allow us to merge other constants together if the
// second level constants have initializers which point to the globals that
// were just merged.
while (true) {
- // Find the canonical constants others will be merged with.
+ // First: Find the canonical constants others will be merged with.
for (Module::global_iterator GVI = M.global_begin(), E = M.global_end();
GVI != E; ) {
GlobalVariable *GV = &*GVI++;
- Constant *Init = GV->getInitializer();
// If this GV is dead, remove it.
GV->removeDeadConstantUsers();
if (GV->use_empty() && GV->hasLocalLinkage()) {
GV->eraseFromParent();
- ++ChangesMade;
continue;
}
@@ -174,6 +171,8 @@
if (hasMetadataOtherThanDebugLoc(GV))
continue;
+ Constant *Init = GV->getInitializer();
+
// Check to see if the initializer is already known.
GlobalVariable *&Slot = CMap[Init];
@@ -188,14 +187,13 @@
}
}
- // Identify all globals that can be merged together, filling in the
- // SameContentReplacements vector. We cannot do the replacement in this pass
+ // Second: identify all globals that can be merged together, filling in
+ // the Replacements vector. We cannot do the replacement in this pass
// because doing so may cause initializers of other globals to be rewritten,
// invalidating the Constant* pointers in CMap.
for (Module::global_iterator GVI = M.global_begin(), E = M.global_end();
GVI != E; ) {
GlobalVariable *GV = &*GVI++;
- Constant *Init = GV->getInitializer();
// Only process constants with initializers in the default address space.
if (!GV->isConstant() || !GV->hasDefinitiveInitializer() ||
@@ -208,6 +206,8 @@
if (!GV->hasLocalLinkage())
continue;
+ Constant *Init = GV->getInitializer();
+
// Check to see if the initializer is already known.
auto Found = CMap.find(Init);
if (Found == CMap.end())
@@ -223,29 +223,26 @@
// Make all uses of the duplicate constant use the canonical version.
LLVM_DEBUG(dbgs() << "Will replace: @" << GV->getName() << " -> @"
<< Slot->getName() << "\n");
- SameContentReplacements.push_back(std::make_pair(GV, Slot));
+ Replacements.push_back(std::make_pair(GV, Slot));
}
+ if (Replacements.empty())
+ return MadeChange;
+ CMap.clear();
+
// Now that we have figured out which replacements must be made, do them all
// now. This avoid invalidating the pointers in CMap, which are unneeded
// now.
- for (unsigned i = 0, e = SameContentReplacements.size(); i != e; ++i) {
- GlobalVariable *Old = SameContentReplacements[i].first;
- GlobalVariable *New = SameContentReplacements[i].second;
+ for (unsigned i = 0, e = Replacements.size(); i != e; ++i) {
+ GlobalVariable *Old = Replacements[i].first;
+ GlobalVariable *New = Replacements[i].second;
replace(M, Old, New);
- ++ChangesMade;
- ++NumIdenticalMerged;
+ MadeChange = true;
}
- if (ChangesMade == OldChangesMade)
- break;
- OldChangesMade = ChangesMade;
-
- SameContentReplacements.clear();
- CMap.clear();
+ NumMerged += Replacements.size();
+ Replacements.clear();
}
-
- return ChangesMade;
}
PreservedAnalyses ConstantMergePass::run(Module &M, ModuleAnalysisManager &) {