gcov: test switch/break line counts

gcov: test switch/break line counts

The coverage support will under some conditions decide to split edges to
accurately report coverage. By running the test suite with/without this
edge splitting a small diff shows up, addressed by this patch, which
should catch future regressions.

Removing the edge splitting:

$ diff --git a/gcc/profile.cc b/gcc/profile.cc
--- a/gcc/profile.cc
+++ b/gcc/profile.cc
@@ -1244,19 +1244,7 @@ branch_prob (bool thunk)
                Don't do that when the locuses match, so
                if (blah) goto something;
                is not computed twice.  */
-             if (last
-                 && gimple_has_location (last)
-                 && !RESERVED_LOCATION_P (e->goto_locus)
-                 && !single_succ_p (bb)
-                 && (LOCATION_FILE (e->goto_locus)
-                     != LOCATION_FILE (gimple_location (last))
-                     || (LOCATION_LINE (e->goto_locus)
-                         != LOCATION_LINE (gimple_location (last)))))
-               {
-                 basic_block new_bb = split_edge (e);
-                 edge ne = single_succ_edge (new_bb);
-                 ne->goto_locus = e->goto_locus;
-               }
+
        if ((e->flags & (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL))
                && e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
                need_exit_edge = 1;

Assuming the .gcov files from make chec-gcc RUNTESTFLAGS=gcov.exp are
kept:

$ diff -r no-split-edge with-split-edge | grep -C 2 -E "^[<>]\s\s"
diff -r sans-split-edge/gcc/gcov-4.c.gcov with-split-edge/gcc/gcov-4.c.gcov
   228c228
   <         -:  224:        break;
   ---
   >         1:  224:        break;
   231c231
   <         -:  227:        break;
   ---
   >     #####:  227:        break;
   237c237
   <         -:  233:        break;
   ---
   >         2:  233:        break;

gcc/testsuite/ChangeLog:

	* g++.dg/gcov/gcov-1.C: Add line count check.
	* gcc.misc-tests/gcov-4.c: Likewise.