When expanding expressions which are using post-inc mode for multiple loops,
ensure that the expansion is dominated by the increments of those loops.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100748 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 631092b..6eaa93d 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -2820,6 +2820,22 @@
else
Inputs.push_back(IVIncInsertPos);
}
+ // The expansion must also be dominated by the increment positions of any
+ // loops it for which it is using post-inc mode.
+ for (PostIncLoopSet::const_iterator I = LF.PostIncLoops.begin(),
+ E = LF.PostIncLoops.end(); I != E; ++I) {
+ const Loop *PIL = *I;
+ if (PIL == L) continue;
+
+ SmallVector<BasicBlock *, 4> ExitingBlocks;
+ PIL->getExitingBlocks(ExitingBlocks);
+ if (!ExitingBlocks.empty()) {
+ BasicBlock *BB = ExitingBlocks[0];
+ for (unsigned i = 1, e = ExitingBlocks.size(); i != e; ++i)
+ BB = DT.findNearestCommonDominator(BB, ExitingBlocks[i]);
+ Inputs.push_back(BB->getTerminator());
+ }
+ }
// Then, climb up the immediate dominator tree as far as we can go while
// still being dominated by the input positions.