http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57328
Bug ID: 57328
Summary: Missed optimization: Unable to vectorize Fortran min
and max intrinsics
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: spam.brian.taylor at gmail dot com
Created attachment 30145
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30145&action=edit
Test case for vectorization of loops containing max and if
Use of the Fortran min or max intrinsic functions within a loop appears to
prevent vectorization of the loop. Replacement of min or max with conditional
assignment using if statements allows vectorization.
A simple test case using max is attached. If compiled with "gfortran -O2
-msse2 -ftree-vectorize -ftree-vectorizer-verbose=1 -c max_vs_ifs_in_loop.F90",
I get (with extraneous output snipped):
...
max_vs_ifs_in_loop.F90:1: note: vectorized 0 loops in function.
...
max_vs_ifs_in_loop.F90:17: note: LOOP VECTORIZED.
...
gfortran should be able to vectorize loops containing min or max, using any
number of arguments to these intrinsics, e.g. "tmp = max(r1, r2, r3, r4)".
Compiler info:
user@host $ gfortran --version
GNU Fortran (GCC) 4.8.0
Copyright (C) 2013 Free Software Foundation, Inc.
GNU Fortran comes with NO WARRANTY, to the extent permitted by law.
You may redistribute copies of GNU Fortran
under the terms of the GNU General Public License.
For more information about these matters, see the file named COPYING
