ARMInstrInfo: Improve isSwiftFastImmShift

An instruction with less than 3 inputs is trivially a fast immediate shift.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183256 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Arnold Schwaighofer 2013-06-04 22:15:43 +00:00
parent 54d63ccdb7
commit ede7eeae32

View File

@ -4152,6 +4152,8 @@ bool ARMBaseInstrInfo::hasNOP() const {
}
bool ARMBaseInstrInfo::isSwiftFastImmShift(const MachineInstr *MI) const {
if (MI->getNumOperands() < 4)
return true;
unsigned ShOpVal = MI->getOperand(3).getImm();
unsigned ShImm = ARM_AM::getSORegOffset(ShOpVal);
// Swift supports faster shifts for: lsl 2, lsl 1, and lsr 1.