Improve live-in calculation for splitted block

  gcc/
    * shrink-wrap.c (move_insn_for_shrink_wrap): Initialize the live-in of new
    created BB as the intersection of live-in from "old_dest" and live-out from
    "bb".

  gcc/testsuite/
    * gcc.target/i386/shrink_wrap_1.c: New test.

From-SVN: r215611

gcc/ChangeLog

+2014-09-25  Jiong Wang  <jiong.wang@arm.com>
+
+	* shrink-wrap.c (move_insn_for_shrink_wrap): Initialize the live-in of
+	new created BB as the intersection of live-in from "old_dest" and
+	live-out from "bb".
+
 2014-09-25  Felix Yang  <felix.yang@huawei.com>
 
 	* lra.c (lra_set_insn_recog_data): Fix typo in comment.

gcc/shrink-wrap.c

@@ -250,16 +250,21 @@ move_insn_for_shrink_wrap (basic_block bb, rtx_insn *insn,
       if (!df_live)
 	return false;
 
+      basic_block old_dest = live_edge->dest;
       next_block = split_edge (live_edge);
 
       /* We create a new basic block.  Call df_grow_bb_info to make sure
 	 all data structures are allocated.  */
       df_grow_bb_info (df_live);
-      bitmap_copy (df_get_live_in (next_block), df_get_live_out (bb));
+
+      bitmap_and (df_get_live_in (next_block), df_get_live_out (bb),
+		  df_get_live_in (old_dest));
       df_set_bb_dirty (next_block);
 
       /* We should not split more than once for a function.  */
-      gcc_assert (!(*split_p));
+      if (*split_p)
+	return false;
+
       *split_p = true;
     }
 

gcc/testsuite/ChangeLog

+2014-09-25  Jiong Wang  <jiong.wang@arm.com>
+
+	* gcc.target/i386/shrink_wrap_1.c: New test.
+
 2014-09-25  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
 
 	PR target/63335

gcc/testsuite/gcc.target/i386/shrink_wrap_1.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-rtl-pro_and_epilogue" } */
+
+enum machine_mode
+{
+  FAKE_0,
+  FAKE_1,
+  FAKE_2,
+  FAKE_3,
+  FAKE_4,
+  FAKE_5,
+  NUM_MACHINE_MODES,
+};
+
+typedef int *rtx;
+typedef long unsigned int size_t;
+extern unsigned char mode_size[NUM_MACHINE_MODES];
+
+extern rtx c_readstr (const char *, enum machine_mode);
+extern rtx convert_to_mode (enum machine_mode, rtx, int);
+extern rtx expand_mult (enum machine_mode, rtx, rtx, rtx, int);
+extern rtx force_reg (enum machine_mode, rtx);
+extern void *memset (void *__s, int __c, size_t __n);
+
+rtx
+builtin_memset_gen_str (void *data, long offset __attribute__ ((__unused__)),
+			enum machine_mode mode)
+{
+  rtx target, coeff;
+  size_t size;
+  char *p;
+
+  size = ((unsigned short) (__builtin_constant_p (mode)
+			    ? mode_size_inline (mode) : mode_size[mode]));
+  if (size == 1)
+    return (rtx) data;
+
+  p = ((char *) __builtin_alloca(sizeof (char) * (size)));
+  memset (p, 1, size);
+  coeff = c_readstr (p, mode);
+
+  target = convert_to_mode (mode, (rtx) data, 1);
+  target = expand_mult (mode, target, coeff, (rtx) 0, 1);
+  return force_reg (mode, target);
+}
+
+/* { dg-final { scan-rtl-dump "Performing shrink-wrapping" "pro_and_epilogue"  } } */
+/* { dg-final { cleanup-rtl-dump "pro_and_epilogue" } } */