cfgbuild.c (find_bb_boundaries): Split blocks containing a barrier.

2009-09-02  David Daney  <ddaney@caviumnetworks.com>

	* cfgbuild.c (find_bb_boundaries): Split blocks containing a
	barrier.
	* emit-rtl.c (prev_nonnote_insn_bb): New function.
	* rtl.h (prev_nonnote_insn_bb): Declare it.

2009-09-02  David Daney  <ddaney@caviumnetworks.com>

	* gcc.c-torture/compile/builtin_unreachable-1.c: New testcase.

From-SVN: r151361

gcc/ChangeLog

+2009-09-02  David Daney  <ddaney@caviumnetworks.com>
+
+	* cfgbuild.c (find_bb_boundaries): Split blocks containing a
+	barrier.
+	* emit-rtl.c (prev_nonnote_insn_bb): New function.
+	* rtl.h (prev_nonnote_insn_bb): Declare it.
+
 2009-09-03  Diego Novillo  <dnovillo@google.com>
 
 	* cgraph.c (cgraph_node_for_decl): New.

gcc/cfgbuild.c

@@ -469,6 +469,13 @@ find_bb_boundaries (basic_block bb)
 	    make_edge (ENTRY_BLOCK_PTR, bb, 0);
 	}
 
+      /* __builtin_unreachable () may cause a barrier to be emitted in
+	 the middle of a BB.  We need to split it in the same manner
+	 as if the barrier were preceded by a control_flow_insn_p
+	 insn.  */
+      if (code == BARRIER && !flow_transfer_insn)
+	flow_transfer_insn = prev_nonnote_insn_bb (insn);
+
       /* In case we've previously seen an insn that effects a control
 	 flow transfer, split the block.  */
       if (flow_transfer_insn && inside_basic_block_p (insn))

gcc/emit-rtl.c

@@ -3082,6 +3082,25 @@ prev_nonnote_insn (rtx insn)
   return insn;
 }
 
+/* Return the previous insn before INSN that is not a NOTE, but stop
+   the search before we enter another basic block.  This routine does
+   not look inside SEQUENCEs.  */
+
+rtx
+prev_nonnote_insn_bb (rtx insn)
+{
+  while (insn)
+    {
+      insn = PREV_INSN (insn);
+      if (insn == 0 || !NOTE_P (insn))
+	break;
+      if (NOTE_INSN_BASIC_BLOCK_P (insn))
+	return NULL_RTX;
+    }
+
+  return insn;
+}
+
 /* Return the next insn after INSN that is not a DEBUG_INSN.  This
    routine does not look inside SEQUENCEs.  */
 

gcc/rtl.h

@@ -1675,6 +1675,7 @@ extern rtx last_call_insn (void);
 extern rtx previous_insn (rtx);
 extern rtx next_insn (rtx);
 extern rtx prev_nonnote_insn (rtx);
+extern rtx prev_nonnote_insn_bb (rtx);
 extern rtx next_nonnote_insn (rtx);
 extern rtx next_nonnote_insn_bb (rtx);
 extern rtx prev_nondebug_insn (rtx);

gcc/testsuite/ChangeLog

+2009-09-02  David Daney  <ddaney@caviumnetworks.com>
+
+	* gcc.c-torture/compile/builtin_unreachable-1.c: New testcase.
+
 2009-09-03  Diego Novillo  <dnovillo@google.com>
 
 	* gcc.dg/gomp/combined-1.c: Adjust expected pattern.

gcc/testsuite/gcc.c-torture/compile/builtin_unreachable-1.c

+void bar (const char *);
+void foo (void)
+{
+  bar ("foo");
+  __builtin_unreachable ();
+}