Hello,
The final tie-breaker in pair_cmp comparator looks strange, it correctly
yields zero for equal expr->symtree-n.sym values, but for unequal values
it produces 0 or 1. This would be correct for C++ STL-style comparators
that require "less-than" predicate to be computed, but not for C qsort.
The comment before the function seems to confirm that the intent was to
indeed sort in ascending gfc_symbol order, but the code is doing mostly
the opposite.
Make the comparator properly anti-commutative by returning -1 in the last
tie-breaker when appropriate.
Bootstrapped and regtested on x86-64, OK for trunk?
* interface.c (pair_cmp): Fix gfc_symbol comparison. Adjust comment.
---
gcc/fortran/interface.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/gcc/fortran/interface.c b/gcc/fortran/interface.c
index 6fe0647..13e2bdd 100644
--- a/gcc/fortran/interface.c
+++ b/gcc/fortran/interface.c
@@ -3294,7 +3294,7 @@ argpair;
order:
- p->a->expr == NULL
- p->a->expr->expr_type != EXPR_VARIABLE
- - growing p->a->expr->symbol. */
+ - by gfc_symbol pointer value (larger first). */
static int
pair_cmp (const void *p1, const void *p2)
@@ -3320,6 +3320,8 @@ pair_cmp (const void *p1, const void *p2)
}
if (a2->expr->expr_type != EXPR_VARIABLE)
return 1;
+ if (a1->expr->symtree->n.sym > a2->expr->symtree->n.sym)
+ return -1;
return a1->expr->symtree->n.sym < a2->expr->symtree->n.sym;
}
--
1.8.3.1
