From 386e26b0e33c6e142e2a456ae670ddc1c2e168a1 Mon Sep 17 00:00:00 2001 From: Wojciech Matyjewicz Date: Sun, 15 Jun 2008 19:07:39 +0000 Subject: Fix PR2434. When scanning for exising binary operator to reuse don't take into account the instrucion pointed by InsertPt. Thanks to it, returning the new value of InsertPt to the InsertBinop() caller can be avoided. The bug was, actually, in visitAddRecExpr() method which wasn't correctly handling changes of InsertPt. There shouldn't be any performance regression, as -gvn pass (run after -indvars) removes any redundant binops. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52291 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/ScalarEvolutionExpander.cpp | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) (limited to 'lib/Analysis/ScalarEvolutionExpander.cpp') diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp index a241960..9872ced 100644 --- a/lib/Analysis/ScalarEvolutionExpander.cpp +++ b/lib/Analysis/ScalarEvolutionExpander.cpp @@ -73,7 +73,7 @@ Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V, /// InsertBinop - Insert the specified binary operator, doing a small amount /// of work to avoid inserting an obviously redundant operation. Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode, Value *LHS, - Value *RHS, Instruction *&InsertPt) { + Value *RHS, Instruction *InsertPt) { // Fold a binop with constant operands. if (Constant *CLHS = dyn_cast(LHS)) if (Constant *CRHS = dyn_cast(RHS)) @@ -81,21 +81,21 @@ Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode, Value *LHS, // Do a quick scan to see if we have this binop nearby. If so, reuse it. unsigned ScanLimit = 6; - for (BasicBlock::iterator IP = InsertPt, E = InsertPt->getParent()->begin(); - ScanLimit; --IP, --ScanLimit) { - if (BinaryOperator *BinOp = dyn_cast(IP)) - if (BinOp->getOpcode() == Opcode && BinOp->getOperand(0) == LHS && - BinOp->getOperand(1) == RHS) { - // If we found the instruction *at* the insert point, insert later - // instructions after it. - if (BinOp == InsertPt) - InsertPt = ++IP; - return BinOp; - } - if (IP == E) break; + BasicBlock::iterator BlockBegin = InsertPt->getParent()->begin(); + if (InsertPt != BlockBegin) { + // Scanning starts from the last instruction before InsertPt. + BasicBlock::iterator IP = InsertPt; + --IP; + for (; ScanLimit; --IP, --ScanLimit) { + if (BinaryOperator *BinOp = dyn_cast(IP)) + if (BinOp->getOpcode() == Opcode && BinOp->getOperand(0) == LHS && + BinOp->getOperand(1) == RHS) + return BinOp; + if (IP == BlockBegin) break; + } } - - // If we don't have + + // If we haven't found this binop, insert it. return BinaryOperator::Create(Opcode, LHS, RHS, "tmp", InsertPt); } -- cgit v1.1