[PATCH v2 03/14] tree-cfg: Fix call to next_discriminator_for_locus()

[Lewis Hyatt]

While testing 64-bit location_t support, I ran into an -fcompare-debug issue
that was traced back here. Despite the name, next_discriminator_for_locus()
is meant to take an integer line number argument, not a location_t. There is
one call site which has been passing a location_t instead. For the most part
that is harmless, although in case there are two CALL stmts on the same line
with different location_t, it may fail to generate a unique discriminator
where it should. Once location_t is configured to be 64-bit, however, it
produces an -fcompare-debug failure which is what I noticed. Fix it by passing
the line number rather than the location_t.

I am not aware of a testcase that demonstrates any observable wrong
behavior, but the file debug/pr53466.C is an example where the discriminator
assignment is indeed different before and after this change.

gcc/ChangeLog:

        * tree-cfg.cc (assign_discriminators): Fix incorrect value passed to
        next_discriminator_for_locus().
---
 gcc/tree-cfg.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/tree-cfg.cc b/gcc/tree-cfg.cc
index 3eede0d61cd..c2100a51a7a 100644
--- a/gcc/tree-cfg.cc
+++ b/gcc/tree-cfg.cc
@@ -1251,7 +1251,7 @@ assign_discriminators (void)
            }
          /* Allocate a new discriminator for CALL stmt.  */
          if (gimple_code (stmt) == GIMPLE_CALL)
-           curr_discr = next_discriminator_for_locus (curr_locus);
+           curr_discr = next_discriminator_for_locus (curr_locus_e.line);
        }
 
       gimple *last = last_nondebug_stmt (bb);