On 20 November 2012 22:10, Zhenqiang Chen zhenqiang.chen@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