* [PATCH] Speedup lookup_constraint for 2-letter constraints
@ 2013-02-19 15:08 Richard Biener
2013-02-19 15:10 ` Jakub Jelinek
0 siblings, 1 reply; 2+ messages in thread
From: Richard Biener @ 2013-02-19 15:08 UTC (permalink / raw)
To: gcc-patches; +Cc: Jakub Jelinek
This speeds up lookup_constraint by allowing the generic folding
for n == 1 strncmp calls to trigger, handling two-letter constraints
by two char comparisons instead of one and a call to strncmp (which
ends up not being inlined because it's considered cold ...).
Bootstrap & regtest pending on x86_64-unknown-linux-gnu.
Ok?
Thanks,
Richard.
2013-02-19 Richard Biener <rguenther@suse.de>
* genpreds.c (write_lookup_constraint): Do not compare first
letter of the constraint again.
Index: gcc/genpreds.c
===================================================================
--- gcc/genpreds.c (revision 196134)
+++ gcc/genpreds.c (working copy)
@@ -945,9 +945,10 @@ write_lookup_constraint (void)
{
do
{
- printf (" if (!strncmp (str, \"%s\", %lu))\n"
+ printf (" if (!strncmp (str + 1, \"%s\", %lu))\n"
" return CONSTRAINT_%s;\n",
- c->name, (unsigned long int) c->namelen, c->c_name);
+ c->name + 1, (unsigned long int) c->namelen - 1,
+ c->c_name);
c = c->next_this_letter;
}
while (c);
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] Speedup lookup_constraint for 2-letter constraints
2013-02-19 15:08 [PATCH] Speedup lookup_constraint for 2-letter constraints Richard Biener
@ 2013-02-19 15:10 ` Jakub Jelinek
0 siblings, 0 replies; 2+ messages in thread
From: Jakub Jelinek @ 2013-02-19 15:10 UTC (permalink / raw)
To: Richard Biener; +Cc: gcc-patches
On Tue, Feb 19, 2013 at 04:07:49PM +0100, Richard Biener wrote:
>
> This speeds up lookup_constraint by allowing the generic folding
> for n == 1 strncmp calls to trigger, handling two-letter constraints
> by two char comparisons instead of one and a call to strncmp (which
> ends up not being inlined because it's considered cold ...).
>
> Bootstrap & regtest pending on x86_64-unknown-linux-gnu.
>
> Ok?
Yes, thanks.
> 2013-02-19 Richard Biener <rguenther@suse.de>
>
> * genpreds.c (write_lookup_constraint): Do not compare first
> letter of the constraint again.
Jakub
^ permalink raw reply [flat|nested] 2+ messages in thread
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2013-02-19 15:08 [PATCH] Speedup lookup_constraint for 2-letter constraints Richard Biener
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