[llvm-commits] [llvm] r130687 - in /llvm/trunk/lib/CodeGen: LiveRangeEdit.cpp LiveRangeEdit.h SplitKit.cpp

[Jakob Stoklund Olesen]

Author: stoklund
Date: Mon May  2 00:29:58 2011
New Revision: 130687

URL: http://llvm.org/viewvc/llvm-project?rev=130687&view=rev
Log:
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.

Modified:
    llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp
    llvm/trunk/lib/CodeGen/LiveRangeEdit.h
    llvm/trunk/lib/CodeGen/SplitKit.cpp

Modified: llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp?rev=130687&r1=130686&r2=130687&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp (original)
+++ llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp Mon May  2 00:29:58 2011
@@ -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) {

Modified: llvm/trunk/lib/CodeGen/LiveRangeEdit.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveRangeEdit.h?rev=130687&r1=130686&r2=130687&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LiveRangeEdit.h (original)
+++ llvm/trunk/lib/CodeGen/LiveRangeEdit.h Mon May  2 00:29:58 2011
@@ -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.

Modified: llvm/trunk/lib/CodeGen/SplitKit.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SplitKit.cpp?rev=130687&r1=130686&r2=130687&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SplitKit.cpp (original)
+++ llvm/trunk/lib/CodeGen/SplitKit.cpp Mon May  2 00:29:58 2011
@@ -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.