re PR fortran/31711 (was "rhs array is changed while assiging to same lhs array")

2007-04-29  Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/31711
	* trans-array.c (gfc_conv_resolve_dependencies): Create a temp
	whenever a dependency is found.

2007-04-29  Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/31711
	* gfortran.dg/dependency_21.f90: New test.

From-SVN: r124269

gcc/fortran/ChangeLog

+2007-04-29  Paul Thomas  <pault@gcc.gnu.org>
+
+	PR fortran/31711
+	* trans-array.c (gfc_conv_resolve_dependencies): Create a temp
+	whenever a dependency is found.
+
 2007-04-28  Tobias Schlter  <tobi@gcc.gnu.org>
 
 	* options.c (gfc_handle_option): Ensure requested free form line

gcc/fortran/trans-array.c

@@ -3001,6 +3001,8 @@ gfc_conv_resolve_dependencies (gfc_loopinfo * loop, gfc_ss * dest,
 	  rref = ss->expr->ref;
 
 	  nDepend = gfc_dep_resolver (lref, rref);
+	  if (nDepend == 1)
+	    break;
 #if 0
 	  /* TODO : loop shifting.  */
 	  if (nDepend == 1)

gcc/testsuite/ChangeLog

+2007-04-29  Paul Thomas  <pault@gcc.gnu.org>
+
+	PR fortran/31711
+	* gfortran.dg/dependency_21.f90: New test.
+
 2007-04-27  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	* gfortran.dg/secnds.f: Use real*8.

gcc/testsuite/gfortran.dg/dependency_21.f90

+! { dg-do run }
+! Test the fix for PR31711 in which the dependency in the assignment
+! at line 18 was detected and then ignored.
+!
+! Contributed by Tobias Ivarsson <thobes@gmail.com>
+!
+program laplsolv
+  IMPLICIT NONE
+  integer, parameter                  :: n = 2
+  double precision,dimension(0:n+1, 0:n+1) :: T
+  integer                             :: i
+
+  T=0.0
+  T(0:n+1 , 0)     = 1.0
+  T(0:n+1 , n+1)   = 1.0
+  T(n+1   , 0:n+1) = 2.0
+
+  T(1:n,1)=(T(0:n-1,1)+T(1:n,1+1)+1d0)
+
+  if (any (T(1:n,1) .ne. 1d0 )) call abort ()
+end program laplsolv