[PATCH] Update BBs in cleanup_barriers pass (PR rtl-optimization/61058)

[Jakub Jelinek]

Hi!

While the cleanup_barriers runs after cleaning up BLOCK_FOR_INSNs,
some targets like i?86/x86_64 choose to populate it again during machine
reorg and some target don't free it at the end of machine reorg.
This patch updates cleanup_barrier pass, so that it adjusts basic block
boundaries and BLOCK_FOR_INSNs in that case, so that we don't crash during
final pass.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2015-01-22  Jakub Jelinek  <ja...@redhat.com>

        PR rtl-optimization/61058
        * jump.c (cleanup_barriers): Update basic block boundaries
        if BLOCK_FOR_INSN is non-NULL on PREV.

        * gcc.dg/pr61058.c: New test.

--- gcc/jump.c.jj       2015-01-15 20:25:30.000000000 +0100
+++ gcc/jump.c  2015-01-22 16:32:11.677709401 +0100
@@ -168,7 +168,27 @@ cleanup_barriers (void)
          if (BARRIER_P (prev))
            delete_insn (insn);
          else if (prev != PREV_INSN (insn))
-           reorder_insns_nobb (insn, insn, prev);
+           {
+             basic_block bb = BLOCK_FOR_INSN (prev);
+             rtx_insn *end = PREV_INSN (insn);
+             reorder_insns_nobb (insn, insn, prev);
+             if (bb)
+               {
+                 /* If the backend called in machine reorg compute_bb_for_insn
+                    and didn't free_bb_for_insn again, preserve basic block
+                    boundaries.  Move the end of basic block to PREV since
+                    it is followed by a barrier now, and clear BLOCK_FOR_INSN
+                    on the following notes.  */
+                 BB_END (bb) = prev;
+                 do
+                   {
+                     prev = NEXT_INSN (prev);
+                     if (prev != insn && BLOCK_FOR_INSN (prev) == bb)
+                       BLOCK_FOR_INSN (prev) = NULL;
+                   }
+                 while (prev != end);
+               }
+           }
        }
     }
   return 0;
--- gcc/testsuite/gcc.dg/pr61058.c.jj   2015-01-22 16:19:16.507023479 +0100
+++ gcc/testsuite/gcc.dg/pr61058.c      2015-01-22 16:19:16.507023479 +0100
@@ -0,0 +1,10 @@
+/* PR rtl-optimization/61058 */
+/* { dg-do compile } */
+/* { dg-options "" } */
+/* { dg-additional-options "-fno-asynchronous-unwind-tables -mtune=atom" { 
target i?86-*-* x86_64-*-* } } */
+
+void
+foo (void)
+{
+  __builtin_unreachable ();
+}

        Jakub