MachineVerifier: subregs so not require defs/valnos on every path

It is fine for subregister ranges to be undefined on some CFG paths as
we may have a "vregX:other_subreg<read-undef> =" def on that path. We
do not (and should not) have live segments for the subregister ranges.
The MachineVerifier should not complain about this.

This is a slight variant of http://llvm.org/PR27705

llvm-svn: 270290

1 files changed, 3 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/MachineVerifier.cpp b/llvm/lib/CodeGen/MachineVerifier.cpp
index 87303952371..eca988499cd 100644
--- a/llvm/lib/CodeGen/MachineVerifier.cpp
+++ b/llvm/lib/CodeGen/MachineVerifier.cpp
@@ -1844,8 +1844,9 @@ void MachineVerifier::verifyLiveRangeSegment(const LiveRange &LR,
       SlotIndex PEnd = LiveInts->getMBBEndIdx(*PI);
       const VNInfo *PVNI = LR.getVNInfoBefore(PEnd);
 
-      // All predecessors must have a live-out value.
-      if (!PVNI) {
+      // All predecessors must have a live-out value if this is not a
+      // subregister liverange.
+      if (!PVNI && LaneMask == 0) {
         report("Register not marked live out of predecessor", *PI);
         report_context(LR, Reg, LaneMask);
         report_context(*VNI);