BBVectorize: Check the input types of shuffles for legality

This fixes a bug where shuffles were being fused such that the
resulting input types were not legal on the target. This would
occur only when both inputs and dependencies were also foldable
operations (such as other shuffles) and there were other connected
pairs in the same block.

llvm-svn: 167731

1 files changed, 6 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/Vectorize/BBVectorize.cpp b/llvm/lib/Transforms/Vectorize/BBVectorize.cpp
index 4653a7d7c8c..93cd27e02d9 100644
--- a/llvm/lib/Transforms/Vectorize/BBVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/BBVectorize.cpp
@@ -483,6 +483,8 @@ namespace {
 
       if (SelectInst *SI = dyn_cast<SelectInst>(I)) {
         T2 = SI->getCondition()->getType();
+      } else if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(I)) {
+        T2 = SI->getOperand(0)->getType();
       }
     }
 
@@ -987,10 +989,11 @@ namespace {
       // We don't want to fuse to a type that will be split, even
       // if the two input types will also be split and there is no other
       // associated cost.
-      unsigned VParts = VTTI->getNumberOfParts(VT1);
-      if (VParts > 1)
+      unsigned VParts1 = VTTI->getNumberOfParts(VT1),
+               VParts2 = VTTI->getNumberOfParts(VT2);
+      if (VParts1 > 1 || VParts2 > 1)
         return false;
-      else if (!VParts && VCost == ICost + JCost)
+      else if ((!VParts1 || !VParts2) && VCost == ICost + JCost)
         return false;
 
       CostSavings = ICost + JCost - VCost;