On 09/24/2015 07:16 PM, Teresa Johnson wrote:
This patch unsets -freorder-blocks-and-partition when -fprofile-use
is not specified. Function splitting was not actually being performed
in that case, as probably_never_executed_bb_p does not distinguish
any basic blocks as being cold vs hot when there is no profile data.
Leaving it enabled, however, causes the assembly code generator to create
(empty) cold sections and labels, leading to unnecessary size overhead.
Bootstrapped and tested on x86-64-unknown-linux-gnu. Ok for trunk?
Thanks,
Teresa
2015-09-24 Teresa Johnson <tejohn...@google.com>
* opts.c (finish_options): Unset -freorder-blocks-and-partition
if not using profile.
Hmm, I'd noticed I was getting that enabled by default. It looks like
you added this default with:
2013-11-19 Teresa Johnson <tejohn...@google.com>
* common/config/i386/i386-common.c: Enable
-freorder-blocks-and-partition at -O2 and up for x86.
* doc/invoke.texi: Update -freorder-blocks-and-partition default.
* opts.c (finish_options): Only warn if -freorder-blocks-and-
partition was set on command line.
(Note that this ChangeLog entry should have mentioned
ix86_option_optimization_table as the variable that was changed).
What has changed between then and now? Also, do we not use
estimates/heuristics when not using a profile?
Bernd
