Speed up Loop::isLCSSAForm by using a binary search and single-entry cache.

This reduces LCSSA pass time from 1.5s to 0.96s when run on eon in release+asserts mode.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29464 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2006-08-02 00:14:16 +00:00
parent d41ae8bc0c
commit 880ddb018a

View File

@ -481,9 +481,14 @@ Value *Loop::getTripCount() const {
/// isLCSSAForm - Return true if the Loop is in LCSSA form
bool Loop::isLCSSAForm() const {
for (Loop::block_iterator BB = block_begin(), E = block_end();
BB != E; ++BB) {
for (BasicBlock::iterator I = (*BB)->begin(), E = (*BB)->end(); I != E; ++I)
// Sort the blocks vector so that we can use binary search to do quick
// lookups.
std::vector<BasicBlock*> LoopBBs(block_begin(), block_end());
std::sort(LoopBBs.begin(), LoopBBs.end());
for (unsigned i = 0, e = LoopBBs.size(); i != e; ++i) {
BasicBlock *BB = LoopBBs[i];
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E;
++UI) {
BasicBlock *UserBB = cast<Instruction>(*UI)->getParent();
@ -492,11 +497,14 @@ bool Loop::isLCSSAForm() const {
UserBB = p->getIncomingBlock(OperandNo/2);
}
if (!contains(UserBB)) {
// Check the current block, as a fast-path. Most values are used in the
// same block they are defined in.
if (UserBB != BB &&
// Otherwise, binary search LoopBBs for this block.
!std::binary_search(LoopBBs.begin(), LoopBBs.end(), UserBB))
return false;
}
}
}
return true;
}