gcc 4.8.3: add patch for PR60155

From gcc bugzilla https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60155

Upstream status: in trunk.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>

--- trunk/gcc/gcse.c	2014/02/12 14:50:06	207726

+++ trunk/gcc/gcse.c	2014/04/04 22:25:51	209134

@@ -2502,6 +2502,65 @@

       }

 }

+struct set_data

+{

+  rtx insn;

+  const_rtx set;

+  int nsets;

+};

+

+/* Increment number of sets and record set in DATA.  */

+

+static void

+record_set_data (rtx dest, const_rtx set, void *data)

+{

+  struct set_data *s = (struct set_data *)data;

+

+  if (GET_CODE (set) == SET)

+    {

+      /* We allow insns having multiple sets, where all but one are

+	 dead as single set insns.  In the common case only a single

+	 set is present, so we want to avoid checking for REG_UNUSED

+	 notes unless necessary.  */

+      if (s->nsets == 1

+	  && find_reg_note (s->insn, REG_UNUSED, SET_DEST (s->set))

+	  && !side_effects_p (s->set))

+	s->nsets = 0;

+

+      if (!s->nsets)

+	{

+	  /* Record this set.  */

+	  s->nsets += 1;

+	  s->set = set;

+	}

+      else if (!find_reg_note (s->insn, REG_UNUSED, dest)

+	       || side_effects_p (set))

+	s->nsets += 1;

+    }

+}

+

+static const_rtx

+single_set_gcse (rtx insn)

+{

+  struct set_data s;

+  rtx pattern;

+  

+  gcc_assert (INSN_P (insn));

+

+  /* Optimize common case.  */

+  pattern = PATTERN (insn);

+  if (GET_CODE (pattern) == SET)

+    return pattern;

+

+  s.insn = insn;

+  s.nsets = 0;

+  note_stores (pattern, record_set_data, &s);

+

+  /* Considered invariant insns have exactly one set.  */

+  gcc_assert (s.nsets == 1);

+  return s.set;

+}

+

 /* Emit move from SRC to DEST noting the equivalence with expression computed

    in INSN.  */

@@ -2509,7 +2568,8 @@

 gcse_emit_move_after (rtx dest, rtx src, rtx insn)

 {

   rtx new_rtx;

-  rtx set = single_set (insn), set2;

+  const_rtx set = single_set_gcse (insn);

+  rtx set2;

   rtx note;

   rtx eqv = NULL_RTX;

@@ -3369,13 +3429,12 @@

 	      FOR_EACH_VEC_ELT (occrs_to_hoist, j, occr)

 		{

 		  rtx insn;

-		  rtx set;

+		  const_rtx set;

 		  gcc_assert (!occr->deleted_p);

 		  insn = occr->insn;

-		  set = single_set (insn);

-		  gcc_assert (set);

+		  set = single_set_gcse (insn);

 		  /* Create a pseudo-reg to store the result of reaching

 		     expressions into.  Get the mode for the new pseudo

@@ -3456,10 +3515,8 @@

 {

   rtx reg;

   enum reg_class pressure_class;

-  rtx set = single_set (insn);

+  const_rtx set = single_set_gcse (insn);

-  /* Considered invariant insns have only one set.  */

-  gcc_assert (set != NULL_RTX);

   reg = SET_DEST (set);

   if (GET_CODE (reg) == SUBREG)

     reg = SUBREG_REG (reg);