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* [Bug fortran/53591] New: Front-end optimize empty string assignments
@ 2012-06-06 13:30 burnus at gcc dot gnu.org
2012-06-07 11:16 ` [Bug fortran/53591] " tkoenig at gcc dot gnu.org
0 siblings, 1 reply; 2+ messages in thread
From: burnus at gcc dot gnu.org @ 2012-06-06 13:30 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53591
Bug #: 53591
Summary: Front-end optimize empty string assignments
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: fortran
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: burnus@gcc.gnu.org
CC: tkoenig@gcc.gnu.org
Based on PR 52861.
I think it would be useful to front-end optimize (frontend-passes.c's
optimize_assignment, utilizing empty_string()):
character(len=5) :: str
str = ' '
[That will create a memmove/memcpy followed by a memset.]
to either
str = '' (RHS length = 0)
[This will use a memset]
or to
str = ' ' (RHS length = LHS length)
[That will use an assignment]
Currently, the middle-end likes a direct assignment better than a memset, but
everything which avoids memmove/memcpy is good.
Cf. also trans-expr.c's gfc_trans_string_copy.
^ permalink raw reply [flat|nested] 2+ messages in thread
* [Bug fortran/53591] Front-end optimize empty string assignments
2012-06-06 13:30 [Bug fortran/53591] New: Front-end optimize empty string assignments burnus at gcc dot gnu.org
@ 2012-06-07 11:16 ` tkoenig at gcc dot gnu.org
0 siblings, 0 replies; 2+ messages in thread
From: tkoenig at gcc dot gnu.org @ 2012-06-07 11:16 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53591
Thomas Koenig <tkoenig at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |FIXED
--- Comment #1 from Thomas Koenig <tkoenig at gcc dot gnu.org> 2012-06-07 11:16:46 UTC ---
Also fixed with the commit for PR 52861.
Closing.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2012-06-06 13:30 [Bug fortran/53591] New: Front-end optimize empty string assignments burnus at gcc dot gnu.org
2012-06-07 11:16 ` [Bug fortran/53591] " tkoenig at gcc dot gnu.org
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