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authorrdivacky <rdivacky@FreeBSD.org>2009-12-15 18:09:07 +0000
committerrdivacky <rdivacky@FreeBSD.org>2009-12-15 18:09:07 +0000
commit40a6fcdb85efd93fe0e36c9552cfb0b18b5eacd6 (patch)
tree076117cdf3579003f07cad4cdf0593347ce58150 /lib/Transforms/Utils/SimplifyCFG.cpp
parente7908924d847e63b02bc82bfaa1709ab9c774dcd (diff)
downloadFreeBSD-src-40a6fcdb85efd93fe0e36c9552cfb0b18b5eacd6.zip
FreeBSD-src-40a6fcdb85efd93fe0e36c9552cfb0b18b5eacd6.tar.gz
Update LLVM to 91430.
Diffstat (limited to 'lib/Transforms/Utils/SimplifyCFG.cpp')
-rw-r--r--lib/Transforms/Utils/SimplifyCFG.cpp63
1 files changed, 0 insertions, 63 deletions
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index 89b0bd9..d7ca45e 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -1589,69 +1589,6 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI) {
return true;
}
-/// EliminateDuplicatePHINodes - Check for and eliminate duplicate PHI
-/// nodes in this block. This doesn't try to be clever about PHI nodes
-/// which differ only in the order of the incoming values, but instcombine
-/// orders them so it usually won't matter.
-///
-bool llvm::EliminateDuplicatePHINodes(BasicBlock *BB) {
- bool Changed = false;
-
- // This implementation doesn't currently consider undef operands
- // specially. Theroetically, two phis which are identical except for
- // one having an undef where the other doesn't could be collapsed.
-
- // Map from PHI hash values to PHI nodes. If multiple PHIs have
- // the same hash value, the element is the first PHI in the
- // linked list in CollisionMap.
- DenseMap<uintptr_t, PHINode *> HashMap;
-
- // Maintain linked lists of PHI nodes with common hash values.
- DenseMap<PHINode *, PHINode *> CollisionMap;
-
- // Examine each PHI.
- for (BasicBlock::iterator I = BB->begin();
- PHINode *PN = dyn_cast<PHINode>(I++); ) {
- // Compute a hash value on the operands. Instcombine will likely have sorted
- // them, which helps expose duplicates, but we have to check all the
- // operands to be safe in case instcombine hasn't run.
- uintptr_t Hash = 0;
- for (User::op_iterator I = PN->op_begin(), E = PN->op_end(); I != E; ++I) {
- // This hash algorithm is quite weak as hash functions go, but it seems
- // to do a good enough job for this particular purpose, and is very quick.
- Hash ^= reinterpret_cast<uintptr_t>(static_cast<Value *>(*I));
- Hash = (Hash << 7) | (Hash >> (sizeof(uintptr_t) * CHAR_BIT - 7));
- }
- // If we've never seen this hash value before, it's a unique PHI.
- std::pair<DenseMap<uintptr_t, PHINode *>::iterator, bool> Pair =
- HashMap.insert(std::make_pair(Hash, PN));
- if (Pair.second) continue;
- // Otherwise it's either a duplicate or a hash collision.
- for (PHINode *OtherPN = Pair.first->second; ; ) {
- if (OtherPN->isIdenticalTo(PN)) {
- // A duplicate. Replace this PHI with its duplicate.
- PN->replaceAllUsesWith(OtherPN);
- PN->eraseFromParent();
- Changed = true;
- break;
- }
- // A non-duplicate hash collision.
- DenseMap<PHINode *, PHINode *>::iterator I = CollisionMap.find(OtherPN);
- if (I == CollisionMap.end()) {
- // Set this PHI to be the head of the linked list of colliding PHIs.
- PHINode *Old = Pair.first->second;
- Pair.first->second = PN;
- CollisionMap[PN] = Old;
- break;
- }
- // Procede to the next PHI in the list.
- OtherPN = I->second;
- }
- }
-
- return Changed;
-}
-
/// SimplifyCFG - This function is used to do simplification of a CFG. For
/// example, it adjusts branches to branches to eliminate the extra hop, it
/// eliminates unreachable basic blocks, and does other "peephole" optimization
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