This patch adds influence of macro TARGET_LOOP_UNROLL_ADJUST during constant
iterations (decide_unroll_constant_iterations).
The macro has been already checked for runtime iterations
(decide_unroll_runtime_iterations), and for unroll stupid
(decide_unroll_stupid).
Bootstrapping and test passes.
Would like to know your comments before committing.
Regards
Ganesh
2013-11-28 Ganesh Gopalasubramanian <ganesh.gopalasubraman...@amd.com>
* loop-unroll.c (decide_unroll_constant_iterations): Check macro
TARGET_LOOP_UNROLL_ADJUST while deciding unroll factor.
diff --git a/gcc/loop-unroll.c b/gcc/loop-unroll.c
index 9c87167..557915f 100644
--- a/gcc/loop-unroll.c
+++ b/gcc/loop-unroll.c
@@ -664,6 +664,9 @@ decide_unroll_constant_iterations (struct loop *loop, int
flags)
if (nunroll > (unsigned) PARAM_VALUE (PARAM_MAX_UNROLL_TIMES))
nunroll = PARAM_VALUE (PARAM_MAX_UNROLL_TIMES);
+ if (targetm.loop_unroll_adjust)
+ nunroll = targetm.loop_unroll_adjust (nunroll, loop);
+
/* Skip big loops. */
if (nunroll <= 1)
{
-----Original Message-----
From: Uros Bizjak [mailto:ubiz...@gmail.com]
Sent: Friday, November 22, 2013 1:46 PM
To: Gopalasubramanian, Ganesh
Cc: gcc-patches@gcc.gnu.org; Richard Guenther <richard.guent...@gmail.com>
(richard.guent...@gmail.com); borntrae...@de.ibm.com; H.J. Lu
(hjl.to...@gmail.com); Jakub Jelinek (ja...@redhat.com)
Subject: Re: [RFC] [PATCH, i386] Adjust unroll factor for bdver3 and bdver4
On Wed, Nov 20, 2013 at 7:26 PM, Gopalasubramanian, Ganesh
<ganesh.gopalasubraman...@amd.com> wrote:
> Steamroller processors contain a loop predictor and a loop buffer, which may
> make unrolling small loops less important.
> When unrolling small loops for steamroller, making the unrolled loop fit in
> the loop buffer should be a priority.
>
> This patch uses a heuristic approach (number of memory references) to decide
> the unrolling factor for small loops.
> This patch has some noise in SPEC 2006 results.
>
> Bootstrapping passes.
>
> I would like to know your comments before committing.
Please split the patch to target-dependant and target-independant part, and get
target-idependant part reviewed first.
