[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  <jakub@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