re PR fortran/63570 ([F2018] Implement 13.7.137 RANDOM INIT (REPEATABLE, IMAGE DISTINCT))

2018-06-01  Steven G. Kargl  <kargl@gcc.gnu.org>

	PR fortran/63570
	* check.c (gfc_check_random_init): New function. Check arguments of
	RANDOM_INIT.
	* gfortran.h (GFC_ISYM_RANDOM_INIT): New enum token.
	* intrinsic.c (add_subroutines): Add RANDOM_INIT to list of 
	subroutines.
	(gfc_check_intrinsic_standard): Introduce Fortran 2018 check.
	* intrinsic.h: Add prototypes for gfc_check_random_init and
	gfc_resolve_random_init
	* intrinsic.texi: Document new intrinsic subprogram.
	* iresolve.c (gfc_resolve_random_init): Resolve routine name.
	* trans-decl.c: Declare gfor_fndecl_random_init
	* trans-intrinsic.c (conv_intrinsic_random_init): New function.
	Translate call to RANDOM_INIT.
	(gfc_conv_intrinsic_subroutine): Call it.
 	* trans.h: Declare gfor_fndecl_random_init
 
2018-06-01  Steven G. Kargl  <kargl@gcc.gnu.org>
 
	PR fortran/63570
	* gfortran.dg/random_init_1.f90: New test.
	* gfortran.dg/random_init_2.f90: New test.
	* gfortran.dg/random_init_3.f90: New test.
	* gfortran.dg/random_init_4.f90: New test.
	* gfortran.dg/random_init_5.f90: New test.
	* gfortran.dg/random_init_6.f90: New test.

2018-06-01  Steven G. Kargl  <kargl@gcc.gnu.org>

	PR fortran/63570
	* libgfortran/Makefile.am: Add random_init.f90 to build.
	* libgfortran/Makefile.in: Regenerated.
	* libgfortran/gfortran.map: Expose symbol for _gfortran_random_init.
	* libgfortran/intrinsics/random_init.f90: Implementation.

From-SVN: r261075

1 files changed, 57 insertions, 2 deletions

diff --git a/gcc/fortran/intrinsic.texi b/gcc/fortran/intrinsic.texi
index adea02a..ca006c9 100644
--- a/gcc/fortran/intrinsic.texi
+++ b/gcc/fortran/intrinsic.texi
@@ -262,6 +262,7 @@ Some basic guidelines for editing this document:
 * @code{RADIX}:         RADIX,     Base of a data model
 * @code{RAN}:           RAN,       Real pseudo-random number
 * @code{RAND}:          RAND,      Real pseudo-random number
+* @code{RANDOM_INIT}:   RANDOM_INIT, Initialize pseudo-random number generator
 * @code{RANDOM_NUMBER}: RANDOM_NUMBER, Pseudo-random number
 * @code{RANDOM_SEED}:   RANDOM_SEED, Initialize a pseudo-random number sequence
 * @code{RANGE}:         RANGE,     Decimal exponent range
@@ -11598,6 +11599,60 @@ end program test_rand
 @end table
 
 
+@node RANDOM_INIT
+@section @code{RANDOM_INIT} --- Initialize a pseudo-random number generator
+@fnindex RANDOM_INIT
+@cindex random number generation, initialization
+
+@table @asis
+@item @emph{Description}:
+Initializes the state of the pseudorandom number generator used by 
+@code{RANDOM_NUMBER}.
+
+@item @emph{Standard}:
+Fortran 2018
+
+@item @emph{Class}:
+Subroutine
+
+@item @emph{Syntax}:
+@code{CALL RANDOM_INIT(REPEATABLE, IMAGE_DISTINCT)}
+
+@item @emph{Arguments}:
+@multitable @columnfractions .20 .75
+@item @var{REPEATABLE} @tab Shall be a scalar with a @code{LOGICAL} type,
+and it is @code{INTENT(IN)}.  If it is @code{.true.}, the seed is set to
+a processor-dependent value that is the same each time @code{RANDOM_INIT}
+is called from the same image.  The term ``same image'' means a single
+instance of program execution.  The sequence of random numbers is different
+for repeated execution of the program.  If it is @code{.false.}, the seed
+is set to a processor-dependent value.
+@item @var{IMAGE_DISTINCT} @tab Shall be a scalar with a
+@code{LOGICAL} type, and it is @code{INTENT(IN)}.  If it is @code{.true.},
+the seed is set to a processor-dependent value that is distinct from th
+seed set by a call to @code{RANDOM_INIT} in another image.  If it is
+@code{.false.}, the seed is set value that does depend which image called
+@code{RANDOM_INIT}.
+@end multitable
+
+@item @emph{Example}:
+@smallexample
+program test_random_seed
+  implicit none
+  real x(3), y(3)
+  call random_init(.true., .true.)
+  call random_number(x)
+  call random_init(.true., .true.)
+  call random_number(y)
+  ! x and y are the same sequence
+  if (any(x /= y)) call abort
+end program test_random_seed
+@end smallexample
+
+@item @emph{See also}:
+@ref{RANDOM_NUMBER}, @ref{RANDOM_SEED}
+@end table
+
 
 @node RANDOM_NUMBER
 @section @code{RANDOM_NUMBER} --- Pseudo-random number
@@ -11643,7 +11698,7 @@ end program
 @end smallexample
 
 @item @emph{See also}:
-@ref{RANDOM_SEED}
+@ref{RANDOM_SEED}, @ref{RANDOM_INIT}
 @end table
 
 
@@ -11713,7 +11768,7 @@ end program test_random_seed
 @end smallexample
 
 @item @emph{See also}:
-@ref{RANDOM_NUMBER}
+@ref{RANDOM_NUMBER}, @ref{RANDOM_INIT}
 @end table