crosstool-ng: patches/gcc/4.7.0/100-PR52734-tree-ssa-tail-merge.patch@7776e8369284

     1 ------------------------------------------------------------------------

     2 r186424 | vries | 2012-04-13 18:44:18 +0200 (Fri, 13 Apr 2012) | 12 lines

     4 2012-04-13  Tom de Vries  <tom@codesourcery.com>

     6 	Backport from mainline r186418.

     8 	2012-04-13  Tom de Vries  <tom@codesourcery.com>

    10 	* tree-ssa-tail-merge.c (gsi_advance_bw_nondebug_nonlocal): Add

    11 	parameters vuse and vuse_escaped.

    12 	(find_duplicate): Init vuse1, vuse2 and vuse_escaped.  Pass to

    13 	gsi_advance_bw_nondebug_nonlocal.  Return if vuse_escaped and

    14 	vuse1 != vuse2.

    16 ------------------------------------------------------------------------

    17 Index: gcc/tree-ssa-tail-merge.c

    18 ===================================================================

    19 --- gcc-4.7.0/gcc/tree-ssa-tail-merge.c	(revision 186423)

    20 +++ gcc-4.7.0/gcc/tree-ssa-tail-merge.c	(revision 186424)

    21 @@ -1123,18 +1123,31 @@

    22      }

    23  }

    25 -/* Let GSI skip backwards over local defs.  */

    26 +/* Let GSI skip backwards over local defs.  Return the earliest vuse in VUSE.

    27 +   Return true in VUSE_ESCAPED if the vuse influenced a SSA_OP_DEF of one of the

    28 +   processed statements.  */

    30  static void

    31 -gsi_advance_bw_nondebug_nonlocal (gimple_stmt_iterator *gsi)

    32 +gsi_advance_bw_nondebug_nonlocal (gimple_stmt_iterator *gsi, tree *vuse,

    33 +				  bool *vuse_escaped)

    34  {

    35    gimple stmt;

    36 +  tree lvuse;

    38    while (true)

    39      {

    40        if (gsi_end_p (*gsi))

    41  	return;

    42        stmt = gsi_stmt (*gsi);

    43 +

    44 +      lvuse = gimple_vuse (stmt);

    45 +      if (lvuse != NULL_TREE)

    46 +	{

    47 +	  *vuse = lvuse;

    48 +	  if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_DEF))

    49 +	    *vuse_escaped = true;

    50 +	}

    51 +

    52        if (!(is_gimple_assign (stmt) && local_def (gimple_get_lhs (stmt))

    53  	    && !gimple_has_side_effects (stmt)))

    54  	return;

    55 @@ -1150,9 +1163,11 @@

    56  {

    57    gimple_stmt_iterator gsi1 = gsi_last_nondebug_bb (bb1);

    58    gimple_stmt_iterator gsi2 = gsi_last_nondebug_bb (bb2);

    59 +  tree vuse1 = NULL_TREE, vuse2 = NULL_TREE;

    60 +  bool vuse_escaped = false;

    62 -  gsi_advance_bw_nondebug_nonlocal (&gsi1);

    63 -  gsi_advance_bw_nondebug_nonlocal (&gsi2);

    64 +  gsi_advance_bw_nondebug_nonlocal (&gsi1, &vuse1, &vuse_escaped);

    65 +  gsi_advance_bw_nondebug_nonlocal (&gsi2, &vuse2, &vuse_escaped);

    67    while (!gsi_end_p (gsi1) && !gsi_end_p (gsi2))

    68      {

    69 @@ -1161,13 +1176,20 @@

    71        gsi_prev_nondebug (&gsi1);

    72        gsi_prev_nondebug (&gsi2);

    73 -      gsi_advance_bw_nondebug_nonlocal (&gsi1);

    74 -      gsi_advance_bw_nondebug_nonlocal (&gsi2);

    75 +      gsi_advance_bw_nondebug_nonlocal (&gsi1, &vuse1, &vuse_escaped);

    76 +      gsi_advance_bw_nondebug_nonlocal (&gsi2, &vuse2, &vuse_escaped);

    77      }

    79    if (!(gsi_end_p (gsi1) && gsi_end_p (gsi2)))

    80      return;

    82 +  /* If the incoming vuses are not the same, and the vuse escaped into an

    83 +     SSA_OP_DEF, then merging the 2 blocks will change the value of the def,

    84 +     which potentially means the semantics of one of the blocks will be changed.

    85 +     TODO: make this check more precise.  */

    86 +  if (vuse_escaped && vuse1 != vuse2)

    87 +    return;

    88 +

    89    if (dump_file)

    90      fprintf (dump_file, "find_duplicates: <bb %d> duplicate of <bb %d>\n",

    91  	     bb1->index, bb2->index);

author	"Yann E. MORIN" <yann.morin.1998@free.fr>
	Tue Jul 31 22:27:29 2012 +0200 (2012-07-31)
changeset 3018	7776e8369284
permissions	-rw-r--r--