return MI->isAsCheapAsAMove();
}
+ /// Return true if the instruction should be sunk by MachineSink.
+ ///
+ /// MachineSink determines on its own whether the instruction is safe to sink;
+ /// this gives the target a hook to override the default behavior with regards
+ /// to which instructions should be sunk.
+ /// The default behavior is to not sink insert_subreg, subreg_to_reg, and
+ /// reg_sequence. These are meant to be close to the source to make it easier
+ /// to coalesce.
+ virtual bool shouldSink(const MachineInstr &MI) const {
+ return !MI.isInsertSubreg() && !MI.isSubregToReg() && !MI.isRegSequence();
+ }
+
/// Re-issue the specified 'original' instruction at the
/// specific location targeting a new destination register.
/// The register in Orig->getOperand(0).getReg() will be substituted by
return true;
}
-static bool AvoidsSinking(MachineInstr *MI, MachineRegisterInfo *MRI) {
- return MI->isInsertSubreg() || MI->isSubregToReg() || MI->isRegSequence();
-}
-
/// collectDebgValues - Scan instructions following MI and collect any
/// matching DBG_VALUEs.
static void collectDebugValues(MachineInstr *MI,
/// instruction out of its current block into a successor.
bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore,
AllSuccsCache &AllSuccessors) {
- // Don't sink insert_subreg, subreg_to_reg, reg_sequence. These are meant to
- // be close to the source to make it easier to coalesce.
- if (AvoidsSinking(MI, MRI))
+ // Don't sink instructions that the target prefers not to sink.
+ if (!TII->shouldSink(*MI))
return false;
// Check if it's safe to move the instruction.