Use instruction itinerary to determine what instructions are 'cheap'.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117348 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 10 insertions, 0 deletions

diff --git a/lib/Target/TargetInstrInfo.cpp b/lib/Target/TargetInstrInfo.cpp
index 7f103226da..62818d0cae 100644
--- a/lib/Target/TargetInstrInfo.cpp
+++ b/lib/Target/TargetInstrInfo.cpp
@@ -94,6 +94,16 @@ TargetInstrInfo::getOperandLatency(const InstrItineraryData *ItinData,
   return ItinData->getOperandLatency(DefClass, DefIdx, UseClass, UseIdx);
 }
 
+bool TargetInstrInfo::hasLowDefLatency(const InstrItineraryData *ItinData,
+                                       const MachineInstr *DefMI,
+                                       unsigned DefIdx) const {
+  if (!ItinData || ItinData->isEmpty())
+    return false;
+
+  unsigned DefClass = DefMI->getDesc().getSchedClass();
+  int DefCycle = ItinData->getOperandCycle(DefClass, DefIdx);
+  return (DefCycle != -1 && DefCycle <= 1);
+}
 
 /// insertNoop - Insert a noop into the instruction stream at the specified
 /// point.