This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

[PATCH] Fix gfortran.dg/forall_1.f90


On Tue, Jun 07, 2005 at 11:11:06AM -0400, Jakub Jelinek wrote:
> FYI, the bug is in the
> forall (i=1:15, j=1:10, a1(j)%k <= j)
>    i2(i,j) = j + i*11
> end forall
> 
> code.  The temp array of logical4 (logical4 temp.26[150]; in my case,
> BTW, does it really have to be logical4, can't be some 8 bit type?)
> is computed correctly (150x .true.), but when used to see
> if i2(i,j) should be stored or not, it advances by 16 logical4s
> each time instead of 15, so in the last round it accesses 10 words
> after the end of the array.

Here is a fix.  gfc_trans_forall_loop was emitting mi += 1 statement
for multi-dimensional loops for each control variable, so we ended up with:
    mi.27 = 0;
    j.25 = 1;
    count.31 = 10;
    <D924>:;
    if (count.31 <= 0)
        goto L.14;
    i.24 = 1;
    count.30 = 15;
    <D925>:;
    if (count.30 <= 0)
        goto L.13;
    mi.43 = mi.27;
    D.926 = temp.26[mi.43];
    if (D.926)
      {
        D.927 = (int8) i.24;
        D.920 = (int8) j.25;
        D.928 = D.920 * 15;
        D.929 = D.927 + D.928;
        D.930 = D.929 + -16;
        D.931 = i.24 * 11;
        D.932 = D.931 + j.25;
        i2[D.930] = D.932;
      }
    i.24 = i.24 + 1;
    mi.27 = mi.27 + 1;		<==== addition in the innermost loop
    count.30 = count.30 - 1;
    goto <D925>;
    L.13:;
    j.25 = j.25 + 1;
    mi.27 = mi.27 + 1;		<==== addition in the outer loop
    count.31 = count.31 - 1;
    goto <D924>;
    L.14:;
Of course we only want to increment it in the innermost loop which
contains the load of the mask.  Here is a fix, tested with no check-f95
failures on x86_64-linux.  Ok for HEAD and 4.0.2?

Alternatively, the increment could be moved to gfc_trans_nested_forall_loop
and body passed as stmtblock_t instead of tree.  This change is shorter
though...

2005-06-07  Jakub Jelinek  <jakub@redhat.com>

	* trans-stmt.c (gfc_trans_forall_loop): Only increment maskindex
	in the innermost loop.

--- gcc/fortran/trans-stmt.c.jj	2005-06-07 12:35:06.000000000 +0200
+++ gcc/fortran/trans-stmt.c	2005-06-07 20:14:35.000000000 +0200
@@ -1365,8 +1365,9 @@ gfc_trans_forall_loop (forall_info *fora
       tmp = build2 (PLUS_EXPR, TREE_TYPE (var), var, step);
       gfc_add_modify_expr (&block, var, tmp);
 
-      /* Advance to the next mask element.  */
-      if (mask_flag)
+      /* Advance to the next mask element.  Only do this for the
+	 innermost loop.  */
+      if (n == 0 && mask_flag)
         {
           mask = forall_tmp->mask;
           maskindex = forall_tmp->maskindex;


	Jakub


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]