Minimize the slot indexes spanned by register ranges created when splitting.
When an interfering live range ends at a dead slot index between two
instructions, make sure that the inserted copy instruction gets a slot index
after the dead ones. This makes it possible to avoid the interference.
Ideally, there shouldn't be interference ending at a deleted instruction, but
physical register coalescing can sometimes do that to sub-registers.
This fixes PR9823.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130687 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveRangeEdit.cpp b/lib/CodeGen/LiveRangeEdit.cpp
index 443cc2e..f8a3dbb 100644
--- a/lib/CodeGen/LiveRangeEdit.cpp
+++ b/lib/CodeGen/LiveRangeEdit.cpp
@@ -140,11 +140,13 @@
const Remat &RM,
LiveIntervals &lis,
const TargetInstrInfo &tii,
- const TargetRegisterInfo &tri) {
+ const TargetRegisterInfo &tri,
+ bool Late) {
assert(RM.OrigMI && "Invalid remat");
tii.reMaterialize(MBB, MI, DestReg, 0, RM.OrigMI, tri);
rematted_.insert(RM.ParentVNI);
- return lis.InsertMachineInstrInMaps(--MI).getDefIndex();
+ return lis.getSlotIndexes()->insertMachineInstrInMaps(--MI, Late)
+ .getDefIndex();
}
void LiveRangeEdit::eraseVirtReg(unsigned Reg, LiveIntervals &LIS) {
diff --git a/lib/CodeGen/LiveRangeEdit.h b/lib/CodeGen/LiveRangeEdit.h
index c008d76..14d227e 100644
--- a/lib/CodeGen/LiveRangeEdit.h
+++ b/lib/CodeGen/LiveRangeEdit.h
@@ -165,7 +165,8 @@
const Remat &RM,
LiveIntervals&,
const TargetInstrInfo&,
- const TargetRegisterInfo&);
+ const TargetRegisterInfo&,
+ bool Late = false);
/// markRematerialized - explicitly mark a value as rematerialized after doing
/// it manually.
diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp
index 427ef94..ac9d72b 100644
--- a/lib/CodeGen/SplitKit.cpp
+++ b/lib/CodeGen/SplitKit.cpp
@@ -579,15 +579,20 @@
SlotIndex Def;
LiveInterval *LI = Edit->get(RegIdx);
+ // We may be trying to avoid interference that ends at a deleted instruction,
+ // so always begin RegIdx 0 early and all others late.
+ bool Late = RegIdx != 0;
+
// Attempt cheap-as-a-copy rematerialization.
LiveRangeEdit::Remat RM(ParentVNI);
if (Edit->canRematerializeAt(RM, UseIdx, true, LIS)) {
- Def = Edit->rematerializeAt(MBB, I, LI->reg, RM, LIS, TII, TRI);
+ Def = Edit->rematerializeAt(MBB, I, LI->reg, RM, LIS, TII, TRI, Late);
} else {
// Can't remat, just insert a copy from parent.
CopyMI = BuildMI(MBB, I, DebugLoc(), TII.get(TargetOpcode::COPY), LI->reg)
.addReg(Edit->getReg());
- Def = LIS.InsertMachineInstrInMaps(CopyMI).getDefIndex();
+ Def = LIS.getSlotIndexes()->insertMachineInstrInMaps(CopyMI, Late)
+ .getDefIndex();
}
// Define the value in Reg.