From 9181801bb7d3c6ac18b4b05acf08a1405c2ffb5d Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sat, 4 Aug 2007 02:15:24 +0000 Subject: [PATCH] In mem2reg, when handling the single-store case, make sure to remove a using block from the list if we handle it. Not doing this caused us to not be able to promote (with the fast path) allocas which have uses (whoops). This increases the # allocas hitting this fastpath from 4042 to 8935 on the testcase in PR1432, speeding up mem2reg by 2.6x llvm-svn: 40809 --- .../Utils/PromoteMemoryToRegister.cpp | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp b/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp index 6be25d6dfe21..5ec5d182c77a 100644 --- a/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp +++ b/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp @@ -531,28 +531,29 @@ void PromoteMem2Reg::run() { /// the value stored. void PromoteMem2Reg::RewriteSingleStoreAlloca(AllocaInst *AI, AllocaInfo &Info) { + StoreInst *OnlyStore = Info.OnlyStore; + // Be aware of loads before the store. std::set ProcessedBlocks; for (unsigned i = 0, e = Info.UsingBlocks.size(); i != e; ++i) { // If the store dominates the block and if we haven't processed it yet, // do so now. - if (!dominates(Info.OnlyStore->getParent(), Info.UsingBlocks[i])) - continue; - - if (!ProcessedBlocks.insert(Info.UsingBlocks[i]).second) + if (!dominates(OnlyStore->getParent(), Info.UsingBlocks[i])) continue; BasicBlock *UseBlock = Info.UsingBlocks[i]; + if (!ProcessedBlocks.insert(UseBlock).second) + continue; // If the use and store are in the same block, do a quick scan to // verify that there are no uses before the store. - if (UseBlock == Info.OnlyStore->getParent()) { + if (UseBlock == OnlyStore->getParent()) { BasicBlock::iterator I = UseBlock->begin(); - for (; &*I != Info.OnlyStore; ++I) { // scan block for store. + for (; &*I != OnlyStore; ++I) { // scan block for store. if (isa(I) && I->getOperand(0) == AI) break; } - if (&*I != Info.OnlyStore) break; // Do not handle this case. + if (&*I != OnlyStore) break; // Do not handle this case. } // Otherwise, if this is a different block or if all uses happen @@ -562,7 +563,7 @@ void PromoteMem2Reg::RewriteSingleStoreAlloca(AllocaInst *AI, I != E; ) { if (LoadInst *LI = dyn_cast(I++)) { if (LI->getOperand(0) == AI) { - LI->replaceAllUsesWith(Info.OnlyStore->getOperand(0)); + LI->replaceAllUsesWith(OnlyStore->getOperand(0)); if (AST && isa(LI->getType())) AST->deleteValue(LI); LI->eraseFromParent(); @@ -572,6 +573,7 @@ void PromoteMem2Reg::RewriteSingleStoreAlloca(AllocaInst *AI, // Finally, remove this block from the UsingBlock set. Info.UsingBlocks[i] = Info.UsingBlocks.back(); + Info.UsingBlocks.pop_back(); --i; --e; } }