[PATCH] Do not move outer binds block for -finstrument-functions or TSAN

[Richard Biener]

I've encountered another case where the assumption that only a
bind vars and its block vars may share a common chain -- for
-finstrument-functions or TSAN the gimplifier violates this,
making the chain shared between different binds vars and block.

This can cause BLOCK_VARs to be dropped (I experienced different
fallout though with unrelated "enhancement" at that spot).

I tracked down this "change" to the merge of the tuples branch
(for -finstrument-functions, TSAN simply copied existing practice).
Obviously not documented.

Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.

Richard.

2016-10-14  Richard Biener  <rguent...@suse.de>

        * gimplify.c (gimplify_function_tree): Do not move the outer
        binds block.

Index: gcc/gimplify.c
===================================================================
--- gcc/gimplify.c      (revision 241102)
+++ gcc/gimplify.c      (working copy)
@@ -12373,10 +12376,7 @@ gimplify_function_tree (tree fndecl)
                                tmp_var);
       gimplify_seq_add_stmt (&body, call);
       gimplify_seq_add_stmt (&body, tf);
-      new_bind = gimple_build_bind (NULL, body, gimple_bind_block (bind));
-      /* Clear the block for BIND, since it is no longer directly inside
-         the function, but within a try block.  */
-      gimple_bind_set_block (bind, NULL);
+      new_bind = gimple_build_bind (NULL, body, NULL);
 
       /* Replace the current function body with the body
          wrapped in the try/finally TF.  */
@@ -12391,10 +12391,7 @@ gimplify_function_tree (tree fndecl)
     {
       gcall *call = gimple_build_call_internal (IFN_TSAN_FUNC_EXIT, 0);
       gimple *tf = gimple_build_try (seq, call, GIMPLE_TRY_FINALLY);
-      gbind *new_bind = gimple_build_bind (NULL, tf, gimple_bind_block (bind));
-      /* Clear the block for BIND, since it is no longer directly inside
-        the function, but within a try block.  */
-      gimple_bind_set_block (bind, NULL);
+      gbind *new_bind = gimple_build_bind (NULL, tf, NULL);
       /* Replace the current function body with the body
         wrapped in the try/finally TF.  */
       seq = NULL;