[ARM] Prevent PerformVCVTCombine from combining a vmul/vcvt with 8 lanes

This would result in a crash since the vcvt used does not support v8i32 types.

llvm-svn: 224332

1 files changed, 5 insertions, 3 deletions

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index 3fce38e2e3d..e908c42e975 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -9355,16 +9355,18 @@ static SDValue PerformVCVTCombine(SDNode *N,
 
   MVT FloatTy = Op.getSimpleValueType().getVectorElementType();
   MVT IntTy = N->getSimpleValueType(0).getVectorElementType();
-  if (FloatTy.getSizeInBits() != 32 || IntTy.getSizeInBits() > 32) {
+  unsigned NumLanes = Op.getValueType().getVectorNumElements();
+  if (FloatTy.getSizeInBits() != 32 || IntTy.getSizeInBits() > 32 ||
+      NumLanes > 4) {
     // These instructions only exist converting from f32 to i32. We can handle
     // smaller integers by generating an extra truncate, but larger ones would
-    // be lossy.
+    // be lossy. We also can't handle more then 4 lanes, since these intructions
+    // only support v2i32/v4i32 types.
     return SDValue();
   }
 
   unsigned IntrinsicOpcode = isSigned ? Intrinsic::arm_neon_vcvtfp2fxs :
     Intrinsic::arm_neon_vcvtfp2fxu;
-  unsigned NumLanes = Op.getValueType().getVectorNumElements();
   SDValue FixConv =  DAG.getNode(ISD::INTRINSIC_WO_CHAIN, SDLoc(N),
                                  NumLanes == 2 ? MVT::v2i32 : MVT::v4i32,
                                  DAG.getConstant(IntrinsicOpcode, MVT::i32), N0,