r238114 - in /trunk/gcc: fortran/ChangeLog fort...

[marxin@gcc.gnu.org]

Author: marxin
Date: Thu Jul  7 13:15:39 2016
New Revision: 238114

URL: https://gcc.gnu.org/viewcvs?rev=238114&root=gcc&view=rev
Log:
Optimize fortran loops with +-1 step.

	* gfortran.dg/do_1.f90: Remove a corner case that triggers
	an undefined behavior.
	* gfortran.dg/do_3.F90: Likewise.
	* gfortran.dg/do_check_11.f90: New test.
	* gfortran.dg/do_check_12.f90: New test.
	* gfortran.dg/do_corner_warn.f90: New test.
	* lang.opt (Wundefined-do-loop): New option.
        * resolve.c (gfc_resolve_iterator): Warn for Wundefined-do-loop.
	(gfc_trans_simple_do): Generate a c-style loop.
	(gfc_trans_do): Fix GNU coding style.
	* invoke.texi: Mention the new warning.

Added:
    trunk/gcc/testsuite/gfortran.dg/do_check_11.f90
    trunk/gcc/testsuite/gfortran.dg/do_check_12.f90
    trunk/gcc/testsuite/gfortran.dg/do_corner_warn.f90
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/invoke.texi
    trunk/gcc/fortran/lang.opt
    trunk/gcc/fortran/resolve.c
    trunk/gcc/fortran/trans-stmt.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gfortran.dg/do_1.f90
    trunk/gcc/testsuite/gfortran.dg/do_3.F90
    trunk/gcc/testsuite/gfortran.dg/ldist-1.f90
    trunk/gcc/testsuite/gfortran.dg/pr48636.f90