diff options
Diffstat (limited to 'lib/CodeGen/LiveVariables.cpp')
| -rw-r--r-- | lib/CodeGen/LiveVariables.cpp | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp index 809048e8ef..4b428d6f31 100644 --- a/lib/CodeGen/LiveVariables.cpp +++ b/lib/CodeGen/LiveVariables.cpp @@ -258,8 +258,9 @@ void LiveVariables::HandlePhysRegUse(unsigned Reg, MachineInstr *MI) { bool HasPrevDef = PhysRegInfo[SuperReg] != NULL; if (!HasPrevDef) - // FIXME: This only goes back one level of super-registers. It might miss - // some. + // No need to go up more levels. A def of a register also sets its sub- + // registers. So if PhysRegInfo[SuperReg] is NULL, it means SuperReg's + // super-registers are not previously defined. for (const unsigned *SSRegs = RegInfo->getSuperRegisters(SuperReg); unsigned SSReg = *SSRegs; ++SSRegs) if (PhysRegInfo[SSReg] != NULL) { |