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Re: [ping][patch, ARM] Fix PR42017, LR not used in leaf functions


On 14/05/13 00:24, Chung-Lin Tang wrote:
On 13/5/13 11:15 AM, Kugan wrote:
Hi,

Ping this patch by Chung-Lin.
http://gcc.gnu.org/ml/gcc-patches/2011-05/msg01179.html

This patch allows lr registers to be used in leaf functions for ARM.

There were some concerns about performance regression in thumb2 mode for
CoreMark. However, looking at the code further shows that this
performance regression is due to alignment issue with
core_state_transition function and as a result taking longer time to
execute. In fact, there isn’t any change in the code generated for
core_state_transition with and without the patch. Adding Alignment to
this function improves the performance than without the patch.

Just curious, were changes to enforce the alignment added already? (I'm
quite out of ARM-specific context lately).

Changes to enforce the alignment is not part of the trunk. The thumb2 regressions are not related to your patch and the patch improves performance otherwise.

Thanks,
Kugan

Chung-Lin



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