diff --git a/lib/Transforms/Scalar/LoopIndexSplit.cpp b/lib/Transforms/Scalar/LoopIndexSplit.cpp index 16d3f2f703f..101ff5b2001 100644 --- a/lib/Transforms/Scalar/LoopIndexSplit.cpp +++ b/lib/Transforms/Scalar/LoopIndexSplit.cpp @@ -948,6 +948,25 @@ bool LoopIndexSplit::splitLoop() { 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(Inst) + && !isa(Inst) && !isa(Inst)) + return false; + } + } + // Normalize loop conditions so that it is easier to calculate new loop // bounds. if (IVisGT(*ExitCondition) || IVisGE(*ExitCondition)) { diff --git a/test/Transforms/LoopIndexSplit/PR4174-2.ll b/test/Transforms/LoopIndexSplit/PR4174-2.ll new file mode 100644 index 00000000000..cc17bc0a933 --- /dev/null +++ b/test/Transforms/LoopIndexSplit/PR4174-2.ll @@ -0,0 +1,38 @@ +; RUN: llvm-as < %s | opt -loop-index-split | llvm-dis | not grep clone + +declare void @f() + +define fastcc i32 @main() nounwind { +entry: + br label %bb1552 + +bb1552: + %j295.0.reg2mem.0 = phi i32 [ %storemerge110, %bb1669 ], [ 0, %entry ] + br label %bb1553 + +bb1553: + call void @f() + %tmp1628 = icmp sgt i32 %j295.0.reg2mem.0, -3 + br i1 %tmp1628, label %bb1588, label %bb1616 + +bb1588: + br label %bb1616 + +bb1616: + %tmp1629 = icmp sgt i32 %j295.0.reg2mem.0, -3 + br i1 %tmp1629, label %bb1649, label %bb1632 + +bb1632: + br label %bb1669 + +bb1649: + br label %bb1669 + +bb1669: + %storemerge110 = add i32 %j295.0.reg2mem.0, 1 + %tmp1672 = icmp sgt i32 %storemerge110, 3 + br i1 %tmp1672, label %bb1678, label %bb1552 + +bb1678: + ret i32 0 +} diff --git a/test/Transforms/LoopIndexSplit/PR4174.ll b/test/Transforms/LoopIndexSplit/PR4174.ll new file mode 100644 index 00000000000..e8f5a737f05 --- /dev/null +++ b/test/Transforms/LoopIndexSplit/PR4174.ll @@ -0,0 +1,23 @@ +; RUN: llvm-as < %s | opt -loop-index-split | llvm-dis | not grep clone + +declare void @f() + +define i32 @main() { +entry: + br label %head +head: + %i = phi i32 [0, %entry], [%i1, %tail] + call void @f() + %splitcond = icmp slt i32 %i, 2 + br i1 %splitcond, label %yes, label %no +yes: + br label %tail +no: + br label %tail +tail: + %i1 = add i32 %i, 1 + %exitcond = icmp slt i32 %i1, 4 + br i1 %exitcond, label %head, label %exit +exit: + ret i32 0 +}