[RFC] Change the type of predicates to bool.

diff --git a/gcc/config/i386/i386-expand.c b/gcc/config/i386/i386-expand.c
index e9763eb5b3e..76d6afd6d9d 100644
--- a/gcc/config/i386/i386-expand.c
+++ b/gcc/config/i386/i386-expand.c
@@ -3571,7 +3571,7 @@  ix86_expand_sse_cmp (rtx dest, enum rtx_code code, rtx cmp_op0, rtx cmp_op1,
 
   cmp_op0 = force_reg (cmp_ops_mode, cmp_op0);
 
-  int (*op1_predicate)(rtx, machine_mode)
+  bool (*op1_predicate)(rtx, machine_mode)
     = VECTOR_MODE_P (cmp_ops_mode) ? vector_operand : nonimmediate_operand;
 
   if (!op1_predicate (cmp_op1, cmp_ops_mode))
diff --git a/gcc/genpreds.c b/gcc/genpreds.c
index 63fac0c7d34..9d9715f3d2f 100644
--- a/gcc/genpreds.c
+++ b/gcc/genpreds.c
@@ -110,7 +110,7 @@  process_define_predicate (md_rtx_info *info)
 
    becomes
 
-       static inline int basereg_operand_1(rtx op, machine_mode mode)
+       static inline bool basereg_operand_1(rtx op, machine_mode mode)
        {
          if (GET_CODE (op) == SUBREG)
            op = SUBREG_REG (op);
@@ -151,7 +151,7 @@  write_predicate_subfunction (struct pred_data *p)
 
   p->exp = and_exp;
 
-  printf ("static inline int\n"
+  printf ("static inline bool\n"
 	  "%s_1 (rtx op ATTRIBUTE_UNUSED, machine_mode mode ATTRIBUTE_UNUSED)\n",
 	  p->name);
   rtx_reader_ptr->print_md_ptr_loc (p->c_block);
@@ -651,7 +651,7 @@  write_one_predicate_function (struct pred_data *p)
 
   /* A normal predicate can legitimately not look at machine_mode
      if it accepts only CONST_INTs and/or CONST_WIDE_INT and/or CONST_DOUBLEs.  */
-  printf ("int\n%s (rtx op, machine_mode mode ATTRIBUTE_UNUSED)\n{\n",
+  printf ("bool\n%s (rtx op, machine_mode mode ATTRIBUTE_UNUSED)\n{\n",
 	  p->name);
   write_predicate_stmts (p->exp);
   fputs ("}\n\n", stdout);
@@ -1416,7 +1416,7 @@  write_tm_preds_h (void)
 #ifdef HAVE_MACHINE_MODES");
 
   FOR_ALL_PREDICATES (p)
-    printf ("extern int %s (rtx, machine_mode);\n", p->name);
+    printf ("extern bool %s (rtx, machine_mode);\n", p->name);
 
   puts ("#endif /* HAVE_MACHINE_MODES */\n");
 
diff --git a/gcc/recog.c b/gcc/recog.c
index eb617f11163..9d880433e6f 100644
--- a/gcc/recog.c
+++ b/gcc/recog.c
@@ -1393,7 +1393,7 @@  valid_insn_p (rtx_insn *insn)
   return true;
 }
 
-/* Return 1 if OP is a valid general operand for machine mode MODE.
+/* Return true if OP is a valid general operand for machine mode MODE.
    This is either a register reference, a memory reference,
    or a constant.  In the case of a memory reference, the address
    is checked for general validity for the target machine.
@@ -1407,7 +1407,7 @@  valid_insn_p (rtx_insn *insn)
    The main use of this function is as a predicate in match_operand
    expressions in the machine description.  */
 
-int
+bool
 general_operand (rtx op, machine_mode mode)
 {
   enum rtx_code code = GET_CODE (op);
@@ -1515,13 +1515,13 @@  general_operand (rtx op, machine_mode mode)
   return 0;
 }
 
-/* Return 1 if OP is a valid memory address for a memory reference
+/* Return true if OP is a valid memory address for a memory reference
    of mode MODE.
 
    The main use of this function is as a predicate in match_operand
    expressions in the machine description.  */
 
-int
+bool
 address_operand (rtx op, machine_mode mode)
 {
   /* Wrong mode for an address expr.  */
@@ -1532,13 +1532,13 @@  address_operand (rtx op, machine_mode mode)
   return memory_address_p (mode, op);
 }
 
-/* Return 1 if OP is a register reference of mode MODE.
+/* Return true if OP is a register reference of mode MODE.
    If MODE is VOIDmode, accept a register in any mode.
 
    The main use of this function is as a predicate in match_operand
    expressions in the machine description.  */
 
-int
+bool
 register_operand (rtx op, machine_mode mode)
 {
   if (GET_CODE (op) == SUBREG)
@@ -1559,18 +1559,18 @@  register_operand (rtx op, machine_mode mode)
   return general_operand (op, mode);
 }
 
-/* Return 1 for a register in Pmode; ignore the tested mode.  */
+/* Return true for a register in Pmode; ignore the tested mode.  */
 
-int
+bool
 pmode_register_operand (rtx op, machine_mode mode ATTRIBUTE_UNUSED)
 {
   return register_operand (op, Pmode);
 }
 
-/* Return 1 if OP should match a MATCH_SCRATCH, i.e., if it is a SCRATCH
+/* Return true if OP should match a MATCH_SCRATCH, i.e., if it is a SCRATCH
    or a hard register.  */
 
-int
+bool
 scratch_operand (rtx op, machine_mode mode)
 {
   if (GET_MODE (op) != mode && mode != VOIDmode)
@@ -1583,12 +1583,12 @@  scratch_operand (rtx op, machine_mode mode)
 		      && REGNO_REG_CLASS (REGNO (op)) != NO_REGS))));
 }
 
-/* Return 1 if OP is a valid immediate operand for mode MODE.
+/* Return true if OP is a valid immediate operand for mode MODE.
 
    The main use of this function is as a predicate in match_operand
    expressions in the machine description.  */
 
-int
+bool
 immediate_operand (rtx op, machine_mode mode)
 {
   /* Don't accept CONST_INT or anything similar
@@ -1612,9 +1612,9 @@  immediate_operand (rtx op, machine_mode mode)
 					    : mode, op));
 }
 
-/* Returns 1 if OP is an operand that is a CONST_INT of mode MODE.  */
+/* Return true if OP is an operand that is a CONST_INT of mode MODE.  */
 
-int
+bool
 const_int_operand (rtx op, machine_mode mode)
 {
   if (!CONST_INT_P (op))
@@ -1628,9 +1628,9 @@  const_int_operand (rtx op, machine_mode mode)
 }
 
 #if TARGET_SUPPORTS_WIDE_INT
-/* Returns 1 if OP is an operand that is a CONST_INT or CONST_WIDE_INT
+/* Return true if OP is an operand that is a CONST_INT or CONST_WIDE_INT
    of mode MODE.  */
-int
+bool
 const_scalar_int_operand (rtx op, machine_mode mode)
 {
   if (!CONST_SCALAR_INT_P (op))
@@ -1661,20 +1661,20 @@  const_scalar_int_operand (rtx op, machine_mode mode)
   return 1;
 }
 
-/* Returns 1 if OP is an operand that is a constant integer or constant
+/* Return true if OP is an operand that is a constant integer or constant
    floating-point number of MODE.  */
 
-int
+bool
 const_double_operand (rtx op, machine_mode mode)
 {
   return (GET_CODE (op) == CONST_DOUBLE)
 	  && (GET_MODE (op) == mode || mode == VOIDmode);
 }
 #else
-/* Returns 1 if OP is an operand that is a constant integer or constant
+/* Return true if OP is an operand that is a constant integer or constant
    floating-point number of MODE.  */
 
-int
+bool
 const_double_operand (rtx op, machine_mode mode)
 {
   /* Don't accept CONST_INT or anything similar
@@ -1689,18 +1689,19 @@  const_double_operand (rtx op, machine_mode mode)
 	      || GET_MODE (op) == VOIDmode));
 }
 #endif
-/* Return 1 if OP is a general operand that is not an immediate
+/* Return true if OP is a general operand that is not an immediate
    operand of mode MODE.  */
 
-int
+bool
 nonimmediate_operand (rtx op, machine_mode mode)
 {
   return (general_operand (op, mode) && ! CONSTANT_P (op));
 }
 
-/* Return 1 if OP is a register reference or immediate value of mode MODE.  */
+/* Return true if OP is a register reference or
+   immediate value of mode MODE.  */
 
-int
+bool
 nonmemory_operand (rtx op, machine_mode mode)
 {
   if (CONSTANT_P (op))
@@ -1708,13 +1709,13 @@  nonmemory_operand (rtx op, machine_mode mode)
   return register_operand (op, mode);
 }
 
-/* Return 1 if OP is a valid operand that stands for pushing a
+/* Return true if OP is a valid operand that stands for pushing a
    value of mode MODE onto the stack.
 
    The main use of this function is as a predicate in match_operand
    expressions in the machine description.  */
 
-int
+bool
 push_operand (rtx op, machine_mode mode)
 {
   if (!MEM_P (op))
@@ -1752,13 +1753,13 @@  push_operand (rtx op, machine_mode mode)
   return XEXP (op, 0) == stack_pointer_rtx;
 }
 
-/* Return 1 if OP is a valid operand that stands for popping a
+/* Return true if OP is a valid operand that stands for popping a
    value of mode MODE off the stack.
 
    The main use of this function is as a predicate in match_operand
    expressions in the machine description.  */
 
-int
+bool
 pop_operand (rtx op, machine_mode mode)
 {
   if (!MEM_P (op))
@@ -1794,13 +1795,13 @@  memory_address_addr_space_p (machine_mode mode ATTRIBUTE_UNUSED,
 #endif
 }
 
-/* Return 1 if OP is a valid memory reference with mode MODE,
+/* Return true if OP is a valid memory reference with mode MODE,
    including a valid address.
 
    The main use of this function is as a predicate in match_operand
    expressions in the machine description.  */
 
-int
+bool
 memory_operand (rtx op, machine_mode mode)
 {
   rtx inner;
@@ -1820,10 +1821,10 @@  memory_operand (rtx op, machine_mode mode)
   return (MEM_P (inner) && general_operand (op, mode));
 }
 
-/* Return 1 if OP is a valid indirect memory reference with mode MODE;
+/* Return true if OP is a valid indirect memory reference with mode MODE;
    that is, a memory reference whose address is a general_operand.  */
 
-int
+bool
 indirect_operand (rtx op, machine_mode mode)
 {
   /* Before reload, a SUBREG isn't in memory (see memory_operand, above).  */
@@ -1848,10 +1849,10 @@  indirect_operand (rtx op, machine_mode mode)
 	  && general_operand (XEXP (op, 0), Pmode));
 }
 
-/* Return 1 if this is an ordered comparison operator (not including
+/* Return true if this is an ordered comparison operator (not including
    ORDERED and UNORDERED).  */
 
-int
+bool
 ordered_comparison_operator (rtx op, machine_mode mode)
 {
   if (mode != VOIDmode && GET_MODE (op) != mode)
@@ -1874,10 +1875,10 @@  ordered_comparison_operator (rtx op, machine_mode mode)
     }
 }
 
-/* Return 1 if this is a comparison operator.  This allows the use of
+/* Return true if this is a comparison operator.  This allows the use of
    MATCH_OPERATOR to recognize all the branch insns.  */
 
-int
+bool
 comparison_operator (rtx op, machine_mode mode)
 {
   return ((mode == VOIDmode || GET_MODE (op) == mode)
diff --git a/gcc/recog.h b/gcc/recog.h
index e96e66e99f2..653d0b08184 100644
--- a/gcc/recog.h
+++ b/gcc/recog.h
@@ -393,7 +393,7 @@  which_op_alt ()
 /* A table defined in insn-output.c that give information about
    each insn-code value.  */
 
-typedef int (*insn_operand_predicate_fn) (rtx, machine_mode);
+typedef bool (*insn_operand_predicate_fn) (rtx, machine_mode);
 typedef const char * (*insn_output_fn) (rtx *, rtx_insn *);
 
 struct insn_gen_fn