diff options
Diffstat (limited to 'lib/Target')
| -rw-r--r-- | lib/Target/X86/X86ISelLowering.cpp | 5 | ||||
| -rw-r--r-- | lib/Target/X86/X86ISelLowering.h | 5 |
2 files changed, 10 insertions, 0 deletions
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp index b89eef0fb2..0136f90ec4 100644 --- a/lib/Target/X86/X86ISelLowering.cpp +++ b/lib/Target/X86/X86ISelLowering.cpp @@ -6877,6 +6877,11 @@ bool X86TargetLowering::isZExtFree(MVT VT1, MVT VT2) const { return VT1 == MVT::i32 && VT2 == MVT::i64 && Subtarget->is64Bit(); } +bool X86TargetLowering::isNarrowingProfitable(MVT VT1, MVT VT2) const { + // i16 instructions are longer (0x66 prefix) and potentially slower. + return !(VT1 == MVT::i32 && VT2 == MVT::i16); +} + /// isShuffleMaskLegal - Targets can use this to indicate that they only /// support *some* VECTOR_SHUFFLE operations, those with specific masks. /// By default, if a target supports the VECTOR_SHUFFLE node, all mask values diff --git a/lib/Target/X86/X86ISelLowering.h b/lib/Target/X86/X86ISelLowering.h index badbd2462f..550f8bdf9b 100644 --- a/lib/Target/X86/X86ISelLowering.h +++ b/lib/Target/X86/X86ISelLowering.h @@ -466,6 +466,11 @@ namespace llvm { virtual bool isZExtFree(const Type *Ty1, const Type *Ty2) const; virtual bool isZExtFree(MVT VT1, MVT VT2) const; + /// isNarrowingProfitable - Return true if it's profitable to narrow + /// operations of type VT1 to VT2. e.g. on x86, it's profitable to narrow + /// from i32 to i8 but not from i32 to i16. + virtual bool isNarrowingProfitable(MVT VT1, MVT VT2) const; + /// isShuffleMaskLegal - Targets can use this to indicate that they only /// support *some* VECTOR_SHUFFLE operations, those with specific masks. /// By default, if a target supports the VECTOR_SHUFFLE node, all mask |