Enable early if conversion on PPC
On cores for which we know the misprediction penalty, and we have
the isel instruction, we can profitably perform early if conversion.
This enables us to replace some small branch sequences with selects
and avoid the potential stalls from mispredicting the branches.
Enabling this feature required implementing canInsertSelect and
insertSelect in PPCInstrInfo; isel code in PPCISelLowering was
refactored to use these functions as well.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178926 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCInstrInfo.h b/lib/Target/PowerPC/PPCInstrInfo.h
index 635e348..b851216 100644
--- a/lib/Target/PowerPC/PPCInstrInfo.h
+++ b/lib/Target/PowerPC/PPCInstrInfo.h
@@ -120,6 +120,17 @@
MachineBasicBlock *FBB,
const SmallVectorImpl<MachineOperand> &Cond,
DebugLoc DL) const;
+
+ // Select analysis.
+ virtual bool canInsertSelect(const MachineBasicBlock&,
+ const SmallVectorImpl<MachineOperand> &Cond,
+ unsigned, unsigned, int&, int&, int&) const;
+ virtual void insertSelect(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MI, DebugLoc DL,
+ unsigned DstReg,
+ const SmallVectorImpl<MachineOperand> &Cond,
+ unsigned TrueReg, unsigned FalseReg) const;
+
virtual void copyPhysReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I, DebugLoc DL,
unsigned DestReg, unsigned SrcReg,