[ARM] Fixed an assumption of power-of-2 vector MVT

I am about to introduce some non-power-of-2 width vector MVTs. This
commit fixes a power-of-2 assumption that my forthcoming change would
otherwise break, as shown by test/CodeGen/ARM/vcvt_combine.ll and
vdiv_combine.ll.

Differential Revision: https://reviews.llvm.org/D58927

Change-Id: I56a282e365d3874ab0621e5bdef98a612f702317
llvm-svn: 356341

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index bc985f744d81256ccaff1fc7f9bb1419e7b397e8..b8e60028fd2907f81aed41aa91a8ef13a47a0e2a 100644 (file)
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -12154,11 +12154,11 @@ static SDValue PerformVCVTCombine(SDNode *N, SelectionDAG &DAG,
   MVT IntTy = N->getSimpleValueType(0).getVectorElementType();
   uint32_t IntBits = IntTy.getSizeInBits();
   unsigned NumLanes = Op.getValueType().getVectorNumElements();
-  if (FloatBits != 32 || IntBits > 32 || NumLanes > 4) {
+  if (FloatBits != 32 || IntBits > 32 || (NumLanes != 4 && NumLanes != 2)) {
     // 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. We also can't handle more then 4 lanes, since these intructions
-    // only support v2i32/v4i32 types.
+    // be lossy. We also can't handle anything other than 2 or 4 lanes, since
+    // these intructions only support v2i32/v4i32 types.
     return SDValue();
   }
 
@@ -12212,11 +12212,11 @@ static SDValue PerformVDIVCombine(SDNode *N, SelectionDAG &DAG,
   MVT IntTy = Op.getOperand(0).getSimpleValueType().getVectorElementType();
   uint32_t IntBits = IntTy.getSizeInBits();
   unsigned NumLanes = Op.getValueType().getVectorNumElements();
-  if (FloatBits != 32 || IntBits > 32 || NumLanes > 4) {
+  if (FloatBits != 32 || IntBits > 32 || (NumLanes != 4 && NumLanes != 2)) {
     // These instructions only exist converting from i32 to f32. We can handle
     // smaller integers by generating an extra extend, but larger ones would
-    // be lossy. We also can't handle more then 4 lanes, since these intructions
-    // only support v2i32/v4i32 types.
+    // be lossy. We also can't handle anything other than 2 or 4 lanes, since
+    // these intructions only support v2i32/v4i32 types.
     return SDValue();
   }