misched: cleanup reaching def computation
Ignore undef uses completely.
Use a more explicit SlotIndex API.
Add more explicit comments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151233 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/ScheduleDAGInstrs.cpp b/lib/CodeGen/ScheduleDAGInstrs.cpp
index 29e4df6..2858904 100644
--- a/lib/CodeGen/ScheduleDAGInstrs.cpp
+++ b/lib/CodeGen/ScheduleDAGInstrs.cpp
@@ -408,10 +408,12 @@
// Lookup this operand's reaching definition.
assert(LIS && "vreg dependencies requires LiveIntervals");
- SlotIndex UseIdx = LIS->getSlotIndexes()->getInstructionIndex(MI);
+ SlotIndex UseIdx = LIS->getInstructionIndex(MI).getRegSlot();
LiveInterval *LI = &LIS->getInterval(Reg);
- VNInfo *VNI = LI->getVNInfoAt(UseIdx);
+ VNInfo *VNI = LI->getVNInfoBefore(UseIdx);
+ // VNI will be valid because MachineOperand::readsReg() is checked by caller.
MachineInstr *Def = LIS->getInstructionFromIndex(VNI->def);
+ // Phis and other noninstructions (after coalescing) have a NULL Def.
if (Def) {
SUnit *DefSU = getSUnit(Def);
if (DefSU) {
@@ -540,7 +542,7 @@
assert(!IsPostRA && "Virtual register encountered!");
if (MO.isDef())
addVRegDefDeps(SU, j);
- else
+ else if (MO.readsReg()) // ignore undef operands
addVRegUseDeps(SU, j);
}
}