[llvm-commits] [llvm] r48003 - in /llvm/trunk: include/llvm/CodeGen/RegisterScavenging.h lib/CodeGen/RegisterScavenging.cpp

[Evan Cheng]

On Mar 7, 2008, at 3:44 PM, Bill Wendling wrote:

> On Fri, Mar 7, 2008 at 2:32 PM, Evan Cheng <evan.cheng at apple.com>  
> wrote:
>>
>> On Mar 6, 2008, at 3:22 PM, Bill Wendling wrote:
>>
>>> void RegScavenger::enterBasicBlock(MachineBasicBlock *mbb) {
>>> @@ -138,9 +161,12 @@
>>>    if (MO.isKill() && !isReserved(Reg)) {
>>>      ChangedRegs.set(Reg);
>>>
>>> +      // Mark sub-registers as changed if they aren't defined in
>>> the same
>>> +      // instruction.
>>>      for (const unsigned *SubRegs = TRI->getSubRegisters(Reg);
>>>           unsigned SubReg = *SubRegs; ++SubRegs)
>>> -        ChangedRegs.set(SubReg);
>>> +        if (!RedefinesSuperRegPart(MI, Reg, TRI))
>>
>> Why is this necessary? Something that kills a super-register also
>> kills the sub-register.
>>
> Okay, sure.

Please fix. Thanks.

>
>
>>> @@ -194,7 +224,7 @@
>>>    unsigned Reg = MO.getReg();
>>>    assert(isUsed(Reg));
>>>    if (!isReserved(Reg))
>>> -      setUnused(Reg);
>>> +      setUnused(Reg, MI);
>>
>> What about the sub-registers?
>>
> The setUnused method sets that information, right?

Ah ok.

Evan

>
>
> -bw
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