[APInt] Add an isSplat helper and use it in some places.
To complement getSplat. This is more general than the binary
decomposition method as it also handles non-pow2 splat sizes.
llvm-svn: 233195
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index ff5a0d5..c35ab7a 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -1403,17 +1403,10 @@
// immediate field for would be zero, and we prefer to use vxor for it.
if (ValSizeInBytes < ByteSize) return SDValue();
- // If the element value is larger than the splat value, cut it in half and
- // check to see if the two halves are equal. Continue doing this until we
- // get to ByteSize. This allows us to handle 0x01010101 as 0x01.
- while (ValSizeInBytes > ByteSize) {
- ValSizeInBytes >>= 1;
-
- // If the top half equals the bottom half, we're still ok.
- if (((Value >> (ValSizeInBytes*8)) & ((1 << (8*ValSizeInBytes))-1)) !=
- (Value & ((1 << (8*ValSizeInBytes))-1)))
- return SDValue();
- }
+ // If the element value is larger than the splat value, check if it consists
+ // of a repeated bit pattern of size ByteSize.
+ if (!APInt(ValSizeInBytes * 8, Value).isSplat(ByteSize * 8))
+ return SDValue();
// Properly sign extend the value.
int MaskVal = SignExtend32(Value, ByteSize * 8);