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authorEvan Cheng <evan.cheng@apple.com>2011-12-14 02:28:53 +0000
committerEvan Cheng <evan.cheng@apple.com>2011-12-14 02:28:53 +0000
commit12dfdb424ddcfabb347f168f9332795ba443ccd3 (patch)
tree94bf61e0a2e50579e0ebeb95a4a7c4ed02a0910e
parentdbdc616ed5eb1c92d75465333b0d96b0185f8c8f (diff)
Allow target to specify register output dependency. Still default to one.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146547 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r--include/llvm/Target/TargetInstrInfo.h10
-rw-r--r--lib/CodeGen/ScheduleDAGInstrs.cpp8
2 files changed, 17 insertions, 1 deletions
diff --git a/include/llvm/Target/TargetInstrInfo.h b/include/llvm/Target/TargetInstrInfo.h
index 1903da73e6..957a89af82 100644
--- a/include/llvm/Target/TargetInstrInfo.h
+++ b/include/llvm/Target/TargetInstrInfo.h
@@ -648,6 +648,16 @@ public:
SDNode *DefNode, unsigned DefIdx,
SDNode *UseNode, unsigned UseIdx) const;
+ /// getOutputLatency - Compute and return the output dependency latency of a
+ /// a given pair of defs which both target the same register. This is usually
+ /// one.
+ virtual unsigned getOutputLatency(const InstrItineraryData *ItinData,
+ const MachineInstr *DefMI1,
+ const MachineInstr *DefMI2,
+ unsigned Reg) const {
+ return 1;
+ }
+
/// getInstrLatency - Compute the instruction latency of a given instruction.
/// If the instruction has higher cost when predicated, it's returned via
/// PredCost.
diff --git a/lib/CodeGen/ScheduleDAGInstrs.cpp b/lib/CodeGen/ScheduleDAGInstrs.cpp
index aedc2a13fa..47c533932d 100644
--- a/lib/CodeGen/ScheduleDAGInstrs.cpp
+++ b/lib/CodeGen/ScheduleDAGInstrs.cpp
@@ -278,7 +278,13 @@ void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) {
if (DefSU != SU &&
(Kind != SDep::Output || !MO.isDead() ||
!DefSU->getInstr()->registerDefIsDead(Reg))) {
- DefSU->addPred(SDep(SU, Kind, AOLatency, /*Reg=*/Reg));
+ if (Kind == SDep::Anti)
+ DefSU->addPred(SDep(SU, Kind, 0, /*Reg=*/Reg));
+ else {
+ unsigned AOLat = TII->getOutputLatency(InstrItins, MI,
+ DefSU->getInstr(), Reg);
+ DefSU->addPred(SDep(SU, Kind, AOLat, /*Reg=*/Reg));
+ }
}
}
for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) {