[llvm-commits] [llvm] r73727 - /llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp

[Evan Cheng]

On Jun 18, 2009, at 3:01 PM, Lang Hames wrote:

> Author: lhames
> Date: Thu Jun 18 17:01:47 2009
> New Revision: 73727
>
> URL: http://llvm.org/viewvc/llvm-project?rev=73727&view=rev
> Log:
> Improved PHI def marking, replaced some gotos with breaks.
>
> Modified:
>    llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp
>
> Modified: llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp?rev=73727&r1=73726&r2=73727&view=diff
>
> =
> =
> =
> =
> =
> =
> =
> =
> ======================================================================
> --- llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp (original)
> +++ llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp Thu Jun 18  
> 17:01:47 2009
> @@ -584,7 +584,7 @@
>
>         // Replace the interval with one of a NEW value number.   
> Note that this
>         // value number isn't actually defined by an instruction,  
> weird huh? :)

Please clarify the comment. VN# defined by a phi has imprecise def  
number that points to the start of the BB?

Evan

> -        LiveRange LR(Start, End, interval.getNextValue(0, 0, false,  
> VNInfoAllocator));
> +        LiveRange LR(Start, End, interval.getNextValue(Start, 0,  
> false, VNInfoAllocator));
>         LR.valno->setIsPHIDef(true);
>         DOUT << " replace range with " << LR;
>         interval.addRange(LR);
> @@ -753,7 +753,7 @@
>       DOUT << " killed";
>       end = getUseIndex(baseIndex) + 1;
>       SeenDefUse = true;
> -      goto exit;
> +      break;
>     } else if (mi->modifiesRegister(interval.reg, tri_)) {
>       // Another instruction redefines the register before it is  
> ever read.
>       // Then the register is essentially dead at the instruction  
> that defines
> @@ -762,7 +762,7 @@
>       DOUT << " dead";
>       end = getDefIndex(start) + 1;
>       SeenDefUse = true;
> -      goto exit;
> +      break;
>     }
>
>     baseIndex += InstrSlots::NUM;
> @@ -774,7 +774,6 @@
>     }
>   }
>
> -exit:
>   // Live-in register might not be used at all.
>   if (!SeenDefUse) {
>     if (isAlias) {
> @@ -786,7 +785,10 @@
>     }
>   }
>
> -  LiveRange LR(start, end, interval.getNextValue(0, 0, false,  
> VNInfoAllocator));
> +  VNInfo *vni = interval.getNextValue(start, 0, false,  
> VNInfoAllocator);
> +  vni->setIsPHIDef(true);
> +  LiveRange LR(start, end, vni);
> +
>   interval.addRange(LR);
>   interval.addKill(LR.valno, end);
>   DOUT << " +" << LR << '\n';
>
>
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