From 880ddb018a4bdcff00d35f28988d9eddb557b8e6 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Wed, 2 Aug 2006 00:14:16 +0000 Subject: [PATCH] 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 --- lib/Analysis/LoopInfo.cpp | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp index 49162a66353..0ea513368dc 100644 --- a/lib/Analysis/LoopInfo.cpp +++ b/lib/Analysis/LoopInfo.cpp @@ -480,10 +480,15 @@ 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) +bool Loop::isLCSSAForm() const { + // Sort the blocks vector so that we can use binary search to do quick + // lookups. + std::vector 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(*UI)->getParent(); @@ -492,9 +497,12 @@ 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; - } } }