This PR flags a section of confusing but correct code.
The attach patch rewrites the code to hopefully provide
some clarity. It has lived my tree for around 6 months,
so has sufferred through numerous regression tests.
OK to commit?
2019-06-12 Steven G. Kargl <ka...@gcc.gnu.org>
PR fortran/88810
* dependency.c (gfc_dep_resolver): Re-arrange code to make the logic
a bit more transparent. Fix 2 nearby formatting issues.
--
Steve
Index: gcc/fortran/dependency.c
===================================================================
--- gcc/fortran/dependency.c (revision 268276)
+++ gcc/fortran/dependency.c (working copy)
@@ -2141,7 +2141,7 @@ gfc_dep_resolver (gfc_ref *lref, gfc_ref *rref, gfc_re
/* Index for the reverse array. */
m = -1;
- for (n=0; n < lref->u.ar.dimen; n++)
+ for (n = 0; n < lref->u.ar.dimen; n++)
{
/* Handle dependency when either of array reference is vector
subscript. There is no dependency if the vector indices
@@ -2163,7 +2163,8 @@ gfc_dep_resolver (gfc_ref *lref, gfc_ref *rref, gfc_re
if (lref->u.ar.dimen_type[n] == DIMEN_RANGE
&& rref->u.ar.dimen_type[n] == DIMEN_RANGE)
- this_dep = check_section_vs_section (&lref->u.ar, &rref->u.ar, n);
+ this_dep = check_section_vs_section (&lref->u.ar,
+ &rref->u.ar, n);
else if (lref->u.ar.dimen_type[n] == DIMEN_ELEMENT
&& rref->u.ar.dimen_type[n] == DIMEN_RANGE)
this_dep = gfc_check_element_vs_section (lref, rref, n);
@@ -2196,35 +2197,38 @@ gfc_dep_resolver (gfc_ref *lref, gfc_ref *rref, gfc_re
if (rref->u.ar.dimen_type[n] == DIMEN_RANGE
&& lref->u.ar.dimen_type[n] == DIMEN_RANGE)
{
- /* Set reverse if backward dependence and not inhibited. */
- if (reverse && reverse[m] == GFC_ENABLE_REVERSE)
- reverse[m] = (this_dep == GFC_DEP_BACKWARD) ?
- GFC_REVERSE_SET : reverse[m];
+ if (reverse)
+ {
+ /* Reverse if backward dependence and not inhibited. */
+ if (reverse[m] == GFC_ENABLE_REVERSE
+ && this_dep == GFC_DEP_BACKWARD)
+ reverse[m] = GFC_REVERSE_SET;
- /* Set forward if forward dependence and not inhibited. */
- if (reverse && reverse[m] == GFC_ENABLE_REVERSE)
- reverse[m] = (this_dep == GFC_DEP_FORWARD) ?
- GFC_FORWARD_SET : reverse[m];
+ /* Forward if forward dependence and not inhibited. */
+ if (reverse[m] == GFC_ENABLE_REVERSE
+ && this_dep == GFC_DEP_FORWARD)
+ reverse[m] = GFC_FORWARD_SET;
- /* Flag up overlap if dependence not compatible with
- the overall state of the expression. */
- if (reverse && reverse[m] == GFC_REVERSE_SET
- && this_dep == GFC_DEP_FORWARD)
- {
- reverse[m] = GFC_INHIBIT_REVERSE;
- this_dep = GFC_DEP_OVERLAP;
+ /* Flag up overlap if dependence not compatible with
+ the overall state of the expression. */
+ if (reverse[m] == GFC_REVERSE_SET
+ && this_dep == GFC_DEP_FORWARD)
+ {
+ reverse[m] = GFC_INHIBIT_REVERSE;
+ this_dep = GFC_DEP_OVERLAP;
+ }
+ else if (reverse[m] == GFC_FORWARD_SET
+ && this_dep == GFC_DEP_BACKWARD)
+ {
+ reverse[m] = GFC_INHIBIT_REVERSE;
+ this_dep = GFC_DEP_OVERLAP;
+ }
}
- else if (reverse && reverse[m] == GFC_FORWARD_SET
- && this_dep == GFC_DEP_BACKWARD)
- {
- reverse[m] = GFC_INHIBIT_REVERSE;
- this_dep = GFC_DEP_OVERLAP;
- }
/* If no intention of reversing or reversing is explicitly
inhibited, convert backward dependence to overlap. */
- if ((reverse == NULL && this_dep == GFC_DEP_BACKWARD)
- || (reverse != NULL && reverse[m] == GFC_INHIBIT_REVERSE))
+ if ((!reverse && this_dep == GFC_DEP_BACKWARD)
+ || (reverse && reverse[m] == GFC_INHIBIT_REVERSE))
this_dep = GFC_DEP_OVERLAP;
}
