[llvm] r223896 - MachineVerifier: Allow physreg use if just a subreg is defined.

[Matthias Braun]

Author: matze
Date: Tue Dec  9 19:13:13 2014
New Revision: 223896

URL: http://llvm.org/viewvc/llvm-project?rev=223896&view=rev
Log:
MachineVerifier: Allow physreg use if just a subreg is defined.

We can't mark partially undefined registers, so we have to allow reading
a register in the machine verifier if just parts of a register are
defined.

Modified:
    llvm/trunk/lib/CodeGen/MachineVerifier.cpp

Modified: llvm/trunk/lib/CodeGen/MachineVerifier.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineVerifier.cpp?rev=223896&r1=223895&r2=223896&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineVerifier.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineVerifier.cpp Tue Dec  9 19:13:13 2014
@@ -1066,7 +1066,18 @@ void MachineVerifier::checkLiveness(cons
     if (!regsLive.count(Reg)) {
       if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
         // Reserved registers may be used even when 'dead'.
-        if (!isReserved(Reg))
+        bool Bad = !isReserved(Reg);
+        // We are fine if just any subregister has a defined value.
+        if (Bad) {
+          for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid();
+               ++SubRegs) {
+            if (regsLive.count(*SubRegs)) {
+              Bad = false;
+              break;
+            }
+          }
+        }
+        if (Bad)
           report("Using an undefined physical register", MO, MONum);
       } else if (MRI->def_empty(Reg)) {
         report("Reading virtual register without a def", MO, MONum);