Shrink-wrap on povray

[Zhenqiang Chen]

Hi,

I try ARM, MIPS, PowerPC and X86 on povray benchmark. No one can
shrink-wrap function Ray_In_Bound.

Here is:
bool Ray_In_Bound (RAY *Ray, OBJECT *Bounding_Object)
{
  ...
  for (Bound = Bounding_Object; Bound != NULL; Bound = Bound-Sibling)
  {...}
  return (true);
}
For ARM O2/O3, Bound is allocated to r6 during ira. So there is copy

r6 = r1 before
testing Bound != NULL

The copy (using r6) blocks the shrink-wrap optimization since r6
should be saved. Need enhance shrink-wrap to handle this case.

Overall, for povray benchmark,
54 functions are shrink-wrapped for ARM;
59 functions are shrink-wrapped for X86;
25 functions are shrink-wrapped for MIPS;
26 functions are shrink-wrapped for PowerPC.

Thanks!
-Zhenqiang

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Re: Shrink-wrap on povray

[Michael Hope]

On 20 November 2012 22:10, Zhenqiang Chen zhenqiang.c...@linaro.org wrote:
 Hi,

 I try ARM, MIPS, PowerPC and X86 on povray benchmark. No one can
 shrink-wrap function Ray_In_Bound.

 Here is:
 bool Ray_In_Bound (RAY *Ray, OBJECT *Bounding_Object)
 {
   ...
   for (Bound = Bounding_Object; Bound != NULL; Bound = Bound-Sibling)
   {...}
   return (true);
 }
 For ARM O2/O3, Bound is allocated to r6 during ira. So there is copy

 r6 = r1 before
 testing Bound != NULL

Could you hack the benchmark to make the early exit explicit and see
if that changes the result?  That lets us know if improving shrink
wrap is worthwhile.

Something like:

 bool Ray_In_Bound (RAY *Ray, OBJECT *Bounding_Object)
 {
  if (Bounding_Object == NULL) return true;
   ...
   for (Bound = Bounding_Object; Bound != NULL; Bound = Bound-Sibling)
   {...}
   return (true);
}

-- Michael

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