[llvm] r182490 - Add the IncludeSelf parameter to the MCSubRegIterator and MCSuperRegIterator

[Chad Rosier]

On May 22, 2013, at 2:25 PM, Jakob Stoklund Olesen <stoklund at 2pi.dk> wrote:

> 
> On May 22, 2013, at 11:46 AM, Rafael Espíndola <rafael.espindola at gmail.com> wrote:
> 
>> On 22 May 2013 13:26, Chad Rosier <mcrosier at apple.com> wrote:
>>> Author: mcrosier
>>> Date: Wed May 22 12:26:26 2013
>>> New Revision: 182490
>>> 
>>> URL: http://llvm.org/viewvc/llvm-project?rev=182490&view=rev
>>> Log:
>>> Add the IncludeSelf parameter to the MCSubRegIterator and MCSuperRegIterator
>>> constructors.  No functional change.
>>> Part of rdar://12906217
>> 
>> Can you provide a bit more context on how this will be used?
> 
> Take a look at LiveIntervals::computeRegUnitInterval(). It could be a lot simpler if MCSuperRegIterator also returned Reg itself:
> 
>  // The physregs aliasing Unit are the roots and their super-registers.
>  // Create all values as dead defs before extending to uses. Note that roots
>  // may share super-registers. That's OK because createDeadDefs() is
>  // idempotent. It is very rare for a register unit to have multiple roots, so
>  // uniquing super-registers is probably not worthwhile.
>  for (MCRegUnitRootIterator Roots(Unit, TRI); Roots.isValid(); ++Roots) {
>    unsigned Root = *Roots;
>    if (!MRI->reg_empty(Root))
>      LRCalc->createDeadDefs(LI, Root);
>    for (MCSuperRegIterator Supers(Root, TRI); Supers.isValid(); ++Supers) {
>      if (!MRI->reg_empty(*Supers))
>        LRCalc->createDeadDefs(LI, *Supers);
>    }
>  }
> 
>  // Now extend LI to reach all uses.
>  // Ignore uses of reserved registers. We only track defs of those.
>  for (MCRegUnitRootIterator Roots(Unit, TRI); Roots.isValid(); ++Roots) {
>    unsigned Root = *Roots;
>    if (!MRI->isReserved(Root) && !MRI->reg_empty(Root))
>      LRCalc->extendToUses(LI, Root);
>    for (MCSuperRegIterator Supers(Root, TRI); Supers.isValid(); ++Supers) {
>      unsigned Reg = *Supers;
>      if (!MRI->isReserved(Reg) && !MRI->reg_empty(Reg))
>        LRCalc->extendToUses(LI, Reg);
>    }
>  }

Fixed in llvm revision 182527.

 Chad

> /jakob
>