------- Comment #2 from fxcoudert at gcc dot gnu dot org 2006-10-22 23:14
-------
I've been thinking a bit about this. It's a common case, and it would probably
be worth optimizing it.
We could detect in iresolve.c (gfc_resolve_matmul) that one (or both) of the
arguments to MATMUL is a call to CONJ, and then rewrite the code to be
MATMUL(A,B,2) instead of MATMUL(A,CONJG(B)), where the 2 is an extra "hidden"
integer argument that means here that the second MATMUL arg is to be conjugated
during the matrix multiplication.
After that, we could also detect in iresolve.c (gfc_resolve_conjg) when the
result of a matmul call is conjugated (C = CONJG(MATMUL(A,B))) and optimize
this as well.
Notes for a wannabe coder: that argument a (or b) is the conjg function can be
identified by (a->expr_type == EXPR_FUNCTION &&
a->value.function->isym->generic_id == GFC_ISYM_CONJG). Rewriting the
expressions might be a bit subtle, but not so hard; for the extra argument, see
how the rrspacing and spacing intrinsics are implemented.
--
fxcoudert at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |fxcoudert at gcc dot gnu dot
| |org
Last reconfirmed|2006-10-22 18:45:29 |2006-10-22 23:14:54
date| |
Summary|Optimize -fexternal-blas |Optimize -fexternal-blas
|calls for conj() |calls for conjg()
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29550
