[llvm-commits] CVS: llvm/lib/Analysis/ScalarEvolutionExpander.cpp

[Chris Lattner]

Changes in directory llvm/lib/Analysis:

ScalarEvolutionExpander.cpp updated: 1.16 -> 1.17
---
Log message:

Be more careful when inserting reused instructions.  This fixes CodeGen/Generic/2007-04-17-lsr-crash.ll


---
Diffs of the changes:  (+7 -2)

 ScalarEvolutionExpander.cpp |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)


Index: llvm/lib/Analysis/ScalarEvolutionExpander.cpp
diff -u llvm/lib/Analysis/ScalarEvolutionExpander.cpp:1.16 llvm/lib/Analysis/ScalarEvolutionExpander.cpp:1.17
--- llvm/lib/Analysis/ScalarEvolutionExpander.cpp:1.16	Fri Apr 13 00:04:18 2007
+++ llvm/lib/Analysis/ScalarEvolutionExpander.cpp	Tue Apr 17 18:43:50 2007
@@ -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;
   }