[llvm] r223894 - VirtRegMap: Improve block live-in info if subregister liveness is available.

[David Blaikie]

On Tue, Dec 9, 2014 at 5:13 PM, Matthias Braun <matze at braunis.de> wrote:

> Author: matze
> Date: Tue Dec  9 19:13:08 2014
> New Revision: 223894
>
> URL: http://llvm.org/viewvc/llvm-project?rev=223894&view=rev
> Log:
> VirtRegMap: Improve block live-in info if subregister liveness is
> available.
>
> Modified:
>     llvm/trunk/lib/CodeGen/VirtRegMap.cpp
>
> Modified: llvm/trunk/lib/CodeGen/VirtRegMap.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/VirtRegMap.cpp?rev=223894&r1=223893&r2=223894&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/VirtRegMap.cpp (original)
> +++ llvm/trunk/lib/CodeGen/VirtRegMap.cpp Tue Dec  9 19:13:08 2014
> @@ -252,15 +252,38 @@ void VirtRegRewriter::addMBBLiveIns() {
>      unsigned PhysReg = VRM->getPhys(VirtReg);
>      assert(PhysReg != VirtRegMap::NO_PHYS_REG && "Unmapped virtual
> register.");
>
> -    // Scan the segments of LI.
> -    for (LiveInterval::const_iterator I = LI.begin(), E = LI.end(); I !=
> E;
> -         ++I) {
> -      if (!Indexes->findLiveInMBBs(I->start, I->end, LiveIn))
> -        continue;
> -      for (unsigned i = 0, e = LiveIn.size(); i != e; ++i)
> -        if (!LiveIn[i]->isLiveIn(PhysReg))
> -          LiveIn[i]->addLiveIn(PhysReg);
> -      LiveIn.clear();
> +    if (LI.hasSubRanges()) {
> +      for (LiveInterval::subrange_iterator S = LI.subrange_begin(),
> +           SE = LI.subrange_end(); S != SE; ++S) {
> +        for (LiveRange::const_iterator I = S->begin(), E = S->end(); I !=
> E;
> +             ++I) {
>

Range-for loops? ^


> +          if (!Indexes->findLiveInMBBs(I->start, I->end, LiveIn))
> +            continue;
> +          for (MCSubRegIndexIterator SR(PhysReg, TRI); SR.isValid();
> ++SR) {
>

& perhaps here too (it'd be nice to formulate these custom iterators so
they can be used by range-for loops, if possible)


> +            unsigned SubReg = SR.getSubReg();
> +            unsigned SubRegIndex = SR.getSubRegIndex();
> +            unsigned SubRegLaneMask =
> TRI->getSubRegIndexLaneMask(SubRegIndex);
> +            if ((SubRegLaneMask & S->LaneMask) == 0)
> +              continue;
> +            for (unsigned i = 0, e = LiveIn.size(); i != e; ++i) {
> +              if (!LiveIn[i]->isLiveIn(SubReg))
> +                LiveIn[i]->addLiveIn(SubReg);
> +            }
> +          }
> +          LiveIn.clear();
> +        }
> +      }
> +    } else {
> +      // Scan the segments of LI.
> +      for (LiveInterval::const_iterator I = LI.begin(), E = LI.end(); I
> != E;
> +           ++I) {
>

& here.


> +        if (!Indexes->findLiveInMBBs(I->start, I->end, LiveIn))
> +          continue;
> +        for (unsigned i = 0, e = LiveIn.size(); i != e; ++i)
>

& probably here.


> +          if (!LiveIn[i]->isLiveIn(PhysReg))
> +            LiveIn[i]->addLiveIn(PhysReg);
> +        LiveIn.clear();
> +      }
>      }
>    }
>  }
>
>
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