Be more careful when inserting reused instructions. This fixes CodeGen/Generic/2007-04-17-lsr-crash.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36231 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp
index a9b88c1..c88c781 100644
--- a/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -71,15 +71,20 @@
/// 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) {
// 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<BinaryOperator>(IP))
if (BinOp->getOpcode() == Opcode && BinOp->getOperand(0) == LHS &&
- BinOp->getOperand(1) == RHS)
+ 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;
}