RE: [PATCH,ARM] Define MAX_CONDITIONAL_EXECUTE

["Greta Yorsh" <greta dot yorsh at arm dot com>]

PING...
http://gcc.gnu.org/ml/gcc-patches/2013-06/msg00948.html

Thanks,
Greta

> -----Original Message-----
> From: Greta Yorsh [mailto:greta.yorsh@arm.com]
> Sent: 17 June 2013 12:19
> To: GCC Patches
> Cc: Richard Earnshaw; Ramana Radhakrishnan; paul@codesourcery.com;
> nickc@redhat.com
> Subject: [PATCH,ARM] Define MAX_CONDITIONAL_EXECUTE
> 
> This patch makes the following changes:
> * Define MAX_CONDITIONAL_EXECUTE in arm backend using
> max_insns_skipped,
> which is set based on the current tune.
> * Update max_insns_skipped for Cortex-A15 tune to be 2 (instead of 5).
> * Use max_insns_skipped in thumb2_final_prescan_insn to decide when to
> combine IT blocks
> into larger IT blocks. Previously, max_insns_skipped was only used in
> arm_final_prescan_insn to decide when branch should be converted to
> conditional execution.
> 
> No regression on qemu for arm-none-eabi with cortex-a15 arm/thumb mode.
> Bootstrap successful on Cortex-A15.
> 
> Performance improvement on Cortex-A15 in both arm and thumb states on
> both
> Dhrystone and Coremark, and improvement on Spec2000 in thumb state,
> with all
> benchmarks showing improvements except three benchmarks in CFP2000 that
> have
> slight regressions (189,183,178).
> 
> gcc/ChangeLog
> 
> 2013-06-17  Greta Yorsh  <Greta.Yorsh@arm.com>
> 
> 	* config/arm/arm.h (MAX_CONDITIONAL_EXECUTE): Define macro.
> 	* config/arm/arm-protos.h (arm_max_conditional_execute): New
> 	declaration.
> 	(tune_params): Update comment.
> 	* config/arm/arm.c (arm_cortex_a15_tune): Set max_cond_insns to
> 2.
> 	(arm_max_conditional_execute): New function.
> 	(thumb2_final_prescan_insn): Use max_insn_skipped and
> 	MAX_INSN_PER_IT_BLOCK to compute maximum instructions in a block.