re PR middle-end/86575 (-Wimplicit-fallthrough affects code generation)

Fix PR middle-end/86575

	PR middle-end/86575
	* gimplify.c (collect_fallthrough_labels): Add new argument,
	return location via that, don't modify statements.
	(warn_implicit_fallthrough_r): Adjust call, don't use
	statement location directly.

From-SVN: r266148

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1a70b8f..f83b0ed 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2018-11-14  Michael Matz  <matz@suse.de>
+
+       PR middle-end/86575
+       * gimplify.c (collect_fallthrough_labels): Add new argument,
+       return location via that, don't modify statements.
+       (warn_implicit_fallthrough_r): Adjust call, don't use
+       statement location directly.
+
 2018-11-14  Richard Biener  <rguenther@suse.de>
 
        PR middle-end/87985

diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index ad7f824..017dbbc 100644 (file)
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -1963,10 +1963,12 @@ last_stmt_in_scope (gimple *stmt)
 
 static gimple *
 collect_fallthrough_labels (gimple_stmt_iterator *gsi_p,
-                           auto_vec <struct label_entry> *labels)
+                           auto_vec <struct label_entry> *labels,
+                           location_t *prevloc)
 {
   gimple *prev = NULL;
 
+  *prevloc = UNKNOWN_LOCATION;
   do
     {
       if (gimple_code (gsi_stmt (*gsi_p)) == GIMPLE_BIND)
@@ -2003,7 +2005,7 @@ collect_fallthrough_labels (gimple_stmt_iterator *gsi_p,
              /* It might be a label without a location.  Use the
                 location of the scope then.  */
              if (!gimple_has_location (prev))
-               gimple_set_location (prev, bind_loc);
+               *prevloc = bind_loc;
            }
          gsi_next (gsi_p);
          continue;
@@ -2086,6 +2088,8 @@ collect_fallthrough_labels (gimple_stmt_iterator *gsi_p,
         && (gimple_code (gsi_stmt (*gsi_p)) != GIMPLE_LABEL
             || !gimple_has_location (gsi_stmt (*gsi_p))));
 
+  if (prev && gimple_has_location (prev))
+    *prevloc = gimple_location (prev);
   return prev;
 }
 
@@ -2182,7 +2186,8 @@ warn_implicit_fallthrough_r (gimple_stmt_iterator *gsi_p, bool *handled_ops_p,
 
        /* Vector of labels that fall through.  */
        auto_vec <struct label_entry> labels;
-       gimple *prev = collect_fallthrough_labels (gsi_p, &labels);
+       location_t prevloc;
+       gimple *prev = collect_fallthrough_labels (gsi_p, &labels, &prevloc);
 
        /* There might be no more statements.  */
        if (gsi_end_p (*gsi_p))
@@ -2210,8 +2215,8 @@ warn_implicit_fallthrough_r (gimple_stmt_iterator *gsi_p, bool *handled_ops_p,
                     /* Try to be clever and don't warn when the statement
                        can't actually fall through.  */
                     && gimple_stmt_may_fallthru (prev)
-                    && gimple_has_location (prev))
-             warned_p = warning_at (gimple_location (prev),
+                    && prevloc != UNKNOWN_LOCATION)
+             warned_p = warning_at (prevloc,
                                     OPT_Wimplicit_fallthrough_,
                                     "this statement may fall through");
            if (warned_p)