Check for side effects before splitting loop.
Patch by Jakub Staszak!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@102928 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopIndexSplit.cpp b/lib/Transforms/Scalar/LoopIndexSplit.cpp
index 16d3f2f..101ff5b 100644
--- a/lib/Transforms/Scalar/LoopIndexSplit.cpp
+++ b/lib/Transforms/Scalar/LoopIndexSplit.cpp
@@ -948,6 +948,25 @@
if (!IVBasedValues.count(SplitCondition->getOperand(!SVOpNum)))
return false;
+ // Check for side effects.
+ for (Loop::block_iterator I = L->block_begin(), E = L->block_end();
+ I != E; ++I) {
+ BasicBlock *BB = *I;
+
+ assert(DT->dominates(Header, BB));
+ if (DT->properlyDominates(SplitCondition->getParent(), BB))
+ continue;
+
+ for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
+ BI != BE; ++BI) {
+ Instruction *Inst = BI;
+
+ if (!Inst->isSafeToSpeculativelyExecute() && !isa<PHINode>(Inst)
+ && !isa<BranchInst>(Inst) && !isa<DbgInfoIntrinsic>(Inst))
+ return false;
+ }
+ }
+
// Normalize loop conditions so that it is easier to calculate new loop
// bounds.
if (IVisGT(*ExitCondition) || IVisGE(*ExitCondition)) {