[Bug fortran/44235] array temporary with high upper bound

[dominiq at lps dot ens dot fr]

------- Comment #5 from dominiq at lps dot ens dot fr  2010-08-06 22:49 -------
Note that the following patch I have in my tree for some time now also fix the
pr


--- gcc/fortran/dependency.c    2010-08-07 00:37:34.000000000 +0200
+++ ../work/gcc/fortran/dependency.c    2010-08-05 19:11:58.000000000 +0200
@@ -1172,8 +1172,8 @@ check_section_vs_section (gfc_array_ref 

   /* Check for forward dependencies x:y vs. x+1:z.  */
   if (l_dir == 1 && r_dir == 1
-      && l_start && r_start && gfc_dep_compare_expr (l_start, r_start) == -1
-      && l_end && r_end && gfc_dep_compare_expr (l_end, r_end) == -1)
+      && ((l_start && r_start && gfc_dep_compare_expr (l_start, r_start) ==
-1)
+         || (l_end && r_end && gfc_dep_compare_expr (l_end, r_end) == -1)))
     {
       /* Check that the strides are the same.  */
       if (!l_stride && !r_stride)
@@ -1185,8 +1185,8 @@ check_section_vs_section (gfc_array_ref 

   /* Check for forward dependencies x:y:-1 vs. x-1:z:-1.  */
   if (l_dir == -1 && r_dir == -1
-      && l_start && r_start && gfc_dep_compare_expr (l_start, r_start) == 1
-      && l_end && r_end && gfc_dep_compare_expr (l_end, r_end) == 1)
+      && ((l_start && r_start && gfc_dep_compare_expr (l_start, r_start) == 1)
+         || (l_end && r_end && gfc_dep_compare_expr (l_end, r_end) == 1)))
     {
       /* Check that the strides are the same.  */
       if (!l_stride && !r_stride)

This followed a discussion with Tobias Burnus on IRC. It assumes that the code
is valid, i.e., lhs and rhs has the same extent, otherwise creating a temporary
does make the code valid, even if the result is not the same with or without
temporary.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44235