[Bug rtl-optimization/15473] Sibcall optimization for libcalls.

["chrbr at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #3 from chrbr at gcc dot gnu dot org  2007-09-03 13:24 -------
this report is quite old, but worth to pop :

We found similar problems with implicit memory block copying when using struct
copying by value. (frequent in C++ )

Softfloat architectures making a very extensive use of libcalls are also very
sensitive to this lost optimisation (it is a performance regression since the
optimisation was correctly done with a gcc 3.4.3). The rtl was then emitted
both for normal calls and sibling calls and stored in a "placeholder". The
placeholder was decided to be emitted after all the stmts were expanded. Since
gcc 4.0 the placeholders have disapeared so we lost the ability to optimise
libcalls in the backend.

I will try to make use of the cfg information available in expand to decide if 
we can pass BLOCK_OP_TAILCALL to emit_block_move. I expect that libcalls can
share the same interface. 


-- 

chrbr at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |chrbr at gcc dot gnu dot org
   Last reconfirmed|2006-03-01 02:40:48         |2007-09-03 13:24:57
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15473