6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-07-15 19:24:33 +00:00
Code Issues Projects Releases Wiki Activity

Use information already present in the ValueTable to fast-fail when we know there won't be a value number match. This speeds up GVN on a case where there are very few redundancies by ~25%.

Browse Source 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53108 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson
2008-07-03 17:44:33 +00:00
parent 77a01136ff
commit 0ae33ef202
1 changed files with 11 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
lib/Transforms/Scalar/GVN.cpp
View File

@@ -166,6 +166,7 @@ namespace {
void setAliasAnalysis(AliasAnalysis* A) { AA = A; } void setAliasAnalysis(AliasAnalysis* A) { AA = A; }
void setMemDep(MemoryDependenceAnalysis* M) { MD = M; } void setMemDep(MemoryDependenceAnalysis* M) { MD = M; }
void setDomTree(DominatorTree* D) { DT = D; } void setDomTree(DominatorTree* D) { DT = D; }
uint32_t getNextUnusedValueNumber() { return nextValueNumber; }
}; };
} }
@@ -1058,11 +1059,12 @@ bool GVN::processInstruction(Instruction *I,
return changed; return changed;
} }
uint32_t nextNum = VN.getNextUnusedValueNumber();
unsigned num = VN.lookup_or_add(I); unsigned num = VN.lookup_or_add(I);
// Allocations are always uniquely numbered, so we can save time and memory // Allocations are always uniquely numbered, so we can save time and memory
// by fast failing them. // by fast failing them.
if (isa<AllocationInst>(I)) { if (isa<AllocationInst>(I) || isa<TerminatorInst>(I)) {
localAvail[I->getParent()]->table.insert(std::make_pair(num, I)); localAvail[I->getParent()]->table.insert(std::make_pair(num, I));
return false; return false;
} }
@@ -1082,6 +1084,13 @@ bool GVN::processInstruction(Instruction *I,
} else { } else {
localAvail[I->getParent()]->table.insert(std::make_pair(num, I)); localAvail[I->getParent()]->table.insert(std::make_pair(num, I));
} }
// If the number we were assigned was a brand new VN, then we don't
// need to do a lookup to see if the number already exists
// somewhere in the domtree: it can't!
} else if (num == nextNum) {
localAvail[I->getParent()]->table.insert(std::make_pair(num, I));
// Perform value-number based elimination // Perform value-number based elimination
} else if (Value* repl = lookupNumber(I->getParent(), num)) { } else if (Value* repl = lookupNumber(I->getParent(), num)) {
// Remove it! // Remove it!
@@ -1092,7 +1101,7 @@ bool GVN::processInstruction(Instruction *I,
I->replaceAllUsesWith(repl); I->replaceAllUsesWith(repl);
toErase.push_back(I); toErase.push_back(I);
return true; return true;
} else if (!I->isTerminator()) { } else {
localAvail[I->getParent()]->table.insert(std::make_pair(num, I)); localAvail[I->getParent()]->table.insert(std::make_pair(num, I));
} }