diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelLowering.cpp | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index a0fe4026821..8f2a6ef6264 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -14600,7 +14600,11 @@ static SDValue lowerShuffleWithUndefHalf(const SDLoc &DL, MVT VT, SDValue V1, if (EltWidth == 32 && NumLowerHalves && HalfVT.is128BitVector() && !is128BitUnpackShuffleMask(HalfMask)) return SDValue(); - if (EltWidth == 64) + // If this is a unary shuffle (assume that the 2nd operand is + // canonicalized to undef), then we can use vpermpd. Otherwise, we + // are better off extracting the upper half of 1 operand and using a + // narrow shuffle. + if (EltWidth == 64 && V2.isUndef()) return SDValue(); } // AVX512 has efficient cross-lane shuffles for all legal 512-bit types. |
