https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105691
kargl at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2022-05-22
CC| |kargl at gcc dot gnu.org
Ever confirmed|0 |1
Priority|P3 |P4
Status|UNCONFIRMED |NEW
--- Comment #2 from kargl at gcc dot gnu.org ---
There is some torched logic looking for the substring, which can never find it.
diff --git a/gcc/fortran/simplify.cc b/gcc/fortran/simplify.cc
index 233cc42137f..16b231f5707 100644
--- a/gcc/fortran/simplify.cc
+++ b/gcc/fortran/simplify.cc
@@ -3606,32 +3606,29 @@ gfc_simplify_index (gfc_expr *x, gfc_expr *y, gfc_expr
*b, gfc_expr *kind)
}
else
{
- for (i = 0; i < len; i++)
+ /* Start at the tail of the string, offset by the length of the
+ substring, and search for a match moving towards the head of
+ string. */
+ for (i = len - lensub; i >= 0; i--)
{
- for (j = 0; j < lensub; j++)
+ /* If the first character does not match, then the rest of the
+ string cannot match. */
+ if (x->value.character.string[i]
+ == y->value.character.string[0])
{
- if (y->value.character.string[j]
- == x->value.character.string[len - i])
+
+ /* Compare substring to starting location in string. */
+ for (j = 0, count = 0; j < lensub; j++, count++)
{
- start = len - i;
- if (start <= len - lensub)
- {
- count = 0;
- for (k = 0; k < lensub; k++)
- if (y->value.character.string[k]
- == x->value.character.string[k + start])
- count++;
-
- if (count == lensub)
- {
- index = start + 1;
- goto done;
- }
- }
- else
- {
- continue;
- }
+ if (x->value.character.string[i + j]
+ != y->value.character.string[j])
+ break;
+ }
+
+ if (count == lensub)
+ {
+ index = i + 1;
+ goto done;
}
}
}
