Provide an option to restore old-style if-conversion heuristics for Thumb2.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115339 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/Thumb2InstrInfo.cpp b/lib/Target/ARM/Thumb2InstrInfo.cpp
index 49f5e4a..a79b4ae 100644
--- a/lib/Target/ARM/Thumb2InstrInfo.cpp
+++ b/lib/Target/ARM/Thumb2InstrInfo.cpp
@@ -28,6 +28,11 @@
using namespace llvm;
+static cl::opt<bool>
+OldT2IfCvt("old-thumb2-ifcvt", cl::Hidden,
+ cl::desc("Use old-style Thumb2 if-conversion heuristics"),
+ cl::init(false));
+
Thumb2InstrInfo::Thumb2InstrInfo(const ARMSubtarget &STI)
: ARMBaseInstrInfo(STI), RI(*this, STI) {
}
@@ -37,6 +42,30 @@
return 0;
}
+bool Thumb2InstrInfo::isProfitableToIfCvt(MachineBasicBlock &MBB,
+ unsigned NumInstrs,
+ float Prediction) const {
+ if (!OldT2IfCvt)
+ return ARMBaseInstrInfo::isProfitableToIfCvt(MBB, NumInstrs, Prediction);
+ return NumInstrs && NumInstrs <= 3;
+}
+
+bool Thumb2InstrInfo::
+isProfitableToIfCvt(MachineBasicBlock &TMBB, unsigned NumT,
+ MachineBasicBlock &FMBB, unsigned NumF,
+ float Prediction) const {
+ if (!OldT2IfCvt)
+ return ARMBaseInstrInfo::isProfitableToIfCvt(TMBB, NumT,
+ FMBB, NumF, Prediction);
+
+ // FIXME: Catch optimization such as:
+ // r0 = movne
+ // r0 = moveq
+ return NumT && NumF &&
+ NumT <= 3 && NumF <= 3;
+}
+
+
void
Thumb2InstrInfo::ReplaceTailWithBranchTo(MachineBasicBlock::iterator Tail,
MachineBasicBlock *NewDest) const {