diff options
Diffstat (limited to 'lib/CodeGen/MachineInstr.cpp')
| -rw-r--r-- | lib/CodeGen/MachineInstr.cpp | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp index 97fe6f4893..11ecc84ded 100644 --- a/lib/CodeGen/MachineInstr.cpp +++ b/lib/CodeGen/MachineInstr.cpp @@ -901,7 +901,8 @@ MachineInstr::readsWritesVirtualRegister(unsigned Reg, Ops->push_back(i); if (MO.isUse()) Use |= !MO.isUndef(); - else if (MO.getSubReg()) + else if (MO.getSubReg() && !MO.isUndef()) + // A partial <def,undef> doesn't count as reading the register. PartDef = true; else FullDef = true; |