[PATCH] D92405: [VirtRegRewriter] Insert missing killed flags when tracking subregister liveness

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added inline comments.


================
Comment at: llvm/lib/CodeGen/LiveIntervals.cpp:705-706
-  // Keep track of subregister ranges.
-  SmallVector<std::pair<const LiveInterval::SubRange*,
-                        LiveRange::const_iterator>, 4> SRs;
 
----------------
What was the point of copying out the subranges here before?


================
Comment at: llvm/lib/CodeGen/LiveIntervals.cpp:728-750
+      SlotIndex InstrSI = RI->end;
       // A block index indicates an MBB edge.
-      if (RI->end.isBlock())
+      if (InstrSI.isBlock())
         continue;
-      MachineInstr *MI = getInstructionFromIndex(RI->end);
+      MachineInstr *MI = getInstructionFromIndex(InstrSI);
       if (!MI)
         continue;
----------------
This looks like a separate NFC change


================
Comment at: llvm/lib/CodeGen/LiveIntervals.cpp:794-795
+            if (MO.getSubReg() == 0)
+              if (const TargetRegisterClass *TRC = MRI->getRegClassOrNull(Reg))
+                UseMask = TRC->getLaneMask();
             if ((UseMask & ~DefinedLanesMask).any())
----------------
getRegClass should be sufficient. There can't be a vreg without a class at this point


================
Comment at: llvm/test/CodeGen/PowerPC/subreg-killed.mir:31-101
+name:            test
+alignment:       16
+exposesReturnsTwice: false
+legalized:       false
+regBankSelected: false
+selected:        false
+failedISel:      false
----------------
Should be able to drop most if not all of this


================
Comment at: llvm/test/CodeGen/PowerPC/subreg-killed.mir:110-132
+    undef %14.sub_vsx1:vsrprc_with_sub_64_in_vfrc = COPY $v5
+    %14.sub_vsx0:vsrprc_with_sub_64_in_vfrc = COPY $v4
+    undef %8.sub_vsx1:vsrprc_with_sub_64_in_vfrc = COPY $v3
+    %8.sub_vsx0:vsrprc_with_sub_64_in_vfrc = COPY $v2
+    %4:g8rc_and_g8rc_nox0 = LD 0, %fixed-stack.0 :: (load 8 from %fixed-stack.0, align 16)
+    %8:vsrprc_with_sub_64_in_vfrc = KILL_PAIR %8
+    undef %15.sub_pair0:uaccrc = COPY %8
----------------
Can you simplify this at all? -run-pass=none after deleting the register section will also compact these vreg numbers


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D92405/new/

https://reviews.llvm.org/D92405