[PATCH]: Revise gcse.c to handle parallels TRAP_IF and other RTL codes not handled by single_set

[John David Anglin]

This patch fixes PR rtl-optimization/60155.

The PA backend has a number of INSN patterns which trap on signed  
overflow.  These are
implemented as parallels using the trap_if code.  Currently,  
single_set does not consider
a parallel with a trap_if rtx to be a single set.  This causes an ICE  
in gcse.c when an insn with
a trap_if is encountered.
The problem is fixed by implementing a gcse specific version of  
"single_set" which only
looks at whether there is a single non-dead set in an insn pattern.   
It allows multiple other
sets if they are dead.

Tested on hppa-unknown-linux-gnu, hppa2.0w-hp-hpux11.11 and hppa64-hp- 
hpux11.11.

OK for trunk?

Dave
--
John David Anglin       dave.ang...@bell.net


2014-03-13  John David Anglin  <dang...@gcc.gnu.org>

        PR rtl-optimization/60155
        * gcse.c (record_set_data): New function.
        (single_set_gcse): New function.
        (gcse_emit_move_after): Use single_set_gcse instead of single_set.
        (hoist_code): Likewise.
        (get_pressure_class_and_nregs): Likewise.

Index: gcse.c
===================================================================
--- gcse.c      (revision 208442)
+++ gcse.c      (working copy)
@@ -2502,6 +2502,57 @@
       }
 }
 
+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;
+
+  s.insn = insn;
+  s.nsets = 0;
+  note_stores (PATTERN (insn), 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 +2560,8 @@
 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 +3421,12 @@
              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 +3507,8 @@
 {
   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);