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Re: [patch] Removal of redundant prefetches during loop unrolling
- From: Andrew Pinski <pinskia at physics dot uc dot edu>
- To: Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Fri, 20 Jan 2006 16:47:10 -0500
- Subject: Re: [patch] Removal of redundant prefetches during loop unrolling
- References: <20060120213627.GA15283@atrey.karlin.mff.cuni.cz>
On Jan 20, 2006, at 4:36 PM, Zdenek Dvorak wrote:
The patch was bootstrapped (with -march=athlon -fprefetch-loop-arrays
-funroll-loops)
and regtested on i686.
Zdenek
* loop-unroll.c (PREFETCH_BLOCK): New macro.
Index: loop-unroll.c
===================================================================
*** loop-unroll.c (revision 110005)
--- loop-unroll.c (working copy)
*************** Software Foundation, 51 Franklin Street,
*** 69,74 ****
--- 69,80 ----
showed that this choice may affect performance in order of
several %.
*/
+ /* Provide a default value for prefetch block size, in case md does
not. */
+
+ #ifndef PREFETCH_BLOCK
+ #define PREFETCH_BLOCK 32
+ #endif
+
/* Information about induction variables to split. */
struct iv_to_split
Can you please add this to defaults.h instead as it now used by both
loop.c and loop-unroll.c (yes I know that loop.c is being removed but
it is still better in one place).
Also this define is not documented already in tm.texi even though it
can be
overridden by the targets. It would also be best if you documented it.
Also can you comment on what happens with tree complete unrolling and
someone having a __buitin_prefetch there?
Thanks,
Andrew Pinski