------- Comment #7 from fxcoudert at gcc dot gnu dot org 2008-02-16 18:50
-------
Thomas is right: -fcx-limited-range sets flag_complex_method to 0, but already
with flag_complex_method == 1 we have some rather good figures. Here are the
execution times of 300x300 matmul on my MacBook Pro (i386-apple-darwin8.11.1):
- a home-made triple do loop in Fortran (Janne's comment #2) is 0.1876 sec
- unpatched matmul is 0.5499 sec
- matmul compiled with flag_complex_method == 1 is 0.1448 sec
The following patch is what I used to benchmark: it creates a
-fcx-fortran-rules (of course, we do know that Fortran actually rules, but
hiding it in an option name is a clever way for people to slowly start
realizing it) option that sets flag_complex_method to 1, and uses it to compile
libgfortran's matmul routines.
Index: gcc/toplev.c
===================================================================
--- gcc/toplev.c (revision 132353)
+++ gcc/toplev.c (working copy)
@@ -2001,6 +2001,10 @@
if (flag_cx_limited_range)
flag_complex_method = 0;
+ /* With -fcx-fortran-rules, we do something in-between cheap and C99. */
+ if (flag_cx_fortran_rules)
+ flag_complex_method = 1;
+
/* Targets must be able to place spill slots at lower addresses. If the
target already uses a soft frame pointer, the transition is trivial. */
if (!FRAME_GROWS_DOWNWARD && flag_stack_protect)
Index: gcc/common.opt
===================================================================
--- gcc/common.opt (revision 132353)
+++ gcc/common.opt (working copy)
@@ -390,6 +390,10 @@
Common Report Var(flag_cx_limited_range) Optimization
Omit range reduction step when performing complex division
+fcx-fortran-rules
+Common Report Var(flag_cx_fortran_rules) Optimization
+Complex multiplication and division follow Fortran rules
+
fdata-sections
Common Report Var(flag_data_sections) Optimization
Place data items into their own section
Index: libgfortran/Makefile.am
===================================================================
--- libgfortran/Makefile.am (revision 132353)
+++ libgfortran/Makefile.am (working copy)
@@ -636,7 +636,7 @@
install-pdf:
# Turn on vectorization and loop unrolling for matmul.
-$(patsubst %.c,%.lo,$(notdir $(i_matmul_c))): AM_CFLAGS += -ftree-vectorize
-fs
+$(patsubst %.c,%.lo,$(notdir $(i_matmul_c))): AM_CFLAGS += -ftree-vectorize
-fs
# Logical matmul doesn't vectorize.
$(patsubst %.c,%.lo,$(notdir $(i_matmull_c))): AM_CFLAGS += -funroll-loops
--
fxcoudert at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |fxcoudert at gcc dot gnu dot
| |org
Keywords| |patch
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29549
