[llvm-commits] [llvm] r46790 - /llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp

[Owen Anderson]

Wow, that must be one hell of a CFG you're dealing with. ;-)

--Owen

On Feb 5, 2008, at 6:54 PM, Tanya Lattner wrote:

> Author: tbrethou
> Date: Tue Feb  5 18:54:55 2008
> New Revision: 46790
>
> URL: http://llvm.org/viewvc/llvm-project?rev=46790&view=rev
> Log:
> Throttle the non-local dependence analysis for basic blocks with  
> more than 50 predecessors. Added command line option to play with  
> this threshold.
>
> Modified:
>    llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp
>
> Modified: llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp?rev=46790&r1=46789&r2=46790&view=diff
>
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> ======================================================================
> --- llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp (original)
> +++ llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp Tue Feb  5  
> 18:54:55 2008
> @@ -20,6 +20,7 @@
> #include "llvm/Function.h"
> #include "llvm/Analysis/AliasAnalysis.h"
> #include "llvm/Support/CFG.h"
> +#include "llvm/Support/CommandLine.h"
> #include "llvm/Target/TargetData.h"
> #include "llvm/ADT/Statistic.h"
>
> @@ -27,6 +28,15 @@
>
> using namespace llvm;
>
> +namespace {
> +  // Control the calculation of non-local dependencies by only  
> examining the
> +  // predecessors if the basic block has less than X amount (50 by  
> default).
> +  cl::opt<int>
> +  PredLimit("nonlocaldep-threshold", cl::Hidden, cl::init(50),
> +            cl::desc("Control the calculation of non-local"
> +                     "dependencies (default = 50)"));
> +}
> +
> STATISTIC(NumCacheNonlocal, "Number of cached non-local responses");
> STATISTIC(NumUncacheNonlocal, "Number of uncached non-local  
> responses");
>
> @@ -211,15 +221,18 @@
>     }
>
>     // If we didn't find anything, recurse on the precessors of this  
> block
> +    // Only do this for blocks with a small number of predecessors.
>     bool predOnStack = false;
>     bool inserted = false;
> -    for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
> -         PI != PE; ++PI)
> -      if (!visited.count(*PI)) {
> -        stack.push_back(*PI);
> -        inserted = true;
> -      } else
> -        predOnStack = true;
> +    if (std::distance(pred_begin(BB), pred_end(BB)) <= PredLimit) {
> +      for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
> +           PI != PE; ++PI)
> +        if (!visited.count(*PI)) {
> +          stack.push_back(*PI);
> +          inserted = true;
> +        } else
> +          predOnStack = true;
> +    }
>
>     // If we inserted a new predecessor, then we'll come back to  
> this block
>     if (inserted)
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 2555 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20080205/41d83392/attachment.bin>