[1/10] two hooks for conditional compare (ccmp)

diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index e17ffca..988c288 100644
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -6216,6 +6216,42 @@  A typical @code{ctrap} pattern looks like
   "@dots{}")
 @end smallexample

+@cindex @code{ccmp} instruction pattern
+@item @samp{ccmp}
+Conditional compare instruction.  Operand 2 and 5 are RTLs which perform
+two comparisons.  Operand 1 is AND or IOR, which operates on the result of
+operand 2 and 5.
+It uses recursive method to support more than two compares.  e.g.
+
+  CC0 = CMP (a, b);
+  CC1 = CCMP (NE (CC0, 0), CMP (e, f));
+  ...
+  CCn = CCMP (NE (CCn-1, 0), CMP (...));
+
+Two target hooks are used to generate conditional compares.  GEN_CCMP_FISRT
+is used to generate the first CMP.  And GEN_CCMP_NEXT is used to generate the
+following CCMPs.  Operand 1 is AND or IOR.  Operand 3 is the result of
+GEN_CCMP_FISRT or a previous GEN_CCMP_NEXT.  Operand 2 is NE.
+Operand 4, 5 and 6 is another compare expression.
+
+A typical CCMP pattern looks like
+
+@smallexample
+(define_insn "*ccmp_and_ior"
+  [(set (match_operand 0 "dominant_cc_register" "")
+        (compare
+         (match_operator 1
+          (match_operator 2 "comparison_operator"
+           [(match_operand 3 "dominant_cc_register")
+            (const_int 0)])
+          (match_operator 4 "comparison_operator"
+           [(match_operand 5 "register_operand")
+            (match_operand 6 "compare_operand"]))
+         (const_int 0)))]
+  ""
+  "@dots{}")
+@end smallexample
+
 @cindex @code{prefetch} instruction pattern
 @item @samp{prefetch}
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index c272630..93f7c74 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -11021,6 +11021,23 @@  This target hook is required only when the
target has several different
 modes and they have different conditional execution capability, such as ARM.
 @end deftypefn

+@deftypefn {Target Hook} rtx TARGET_GEN_CCMP_FIRST (int @var{code},
rtx @var{op0}, rtx @var{op1})
+This function emits a comparison insn for the first of a sequence of
+ conditional comparisions.  It returns a comparison expression appropriate
+ for passing to @code{gen_ccmp_next} or to @code{cbranch_optab}.
+ @code{unsignedp} is used when converting @code{op0} and @code{op1}'s mode.
+@end deftypefn
+
+@deftypefn {Target Hook} rtx TARGET_GEN_CCMP_NEXT (rtx @var{prev},
int @var{cmp_code}, rtx @var{op0}, rtx @var{op1}, int @var{bit_code})
+This function emits a conditional comparison within a sequence of
+ conditional comparisons.  The @code{prev} expression is the result of a
+ prior call to @code{gen_ccmp_first} or @code{gen_ccmp_next}.  It may return
+ @code{NULL} if the combination of @code{prev} and this comparison is
+ not supported, otherwise the result must be appropriate for passing to
+ @code{gen_ccmp_next} or @code{cbranch_optab}.  @code{bit_code}
+ is AND or IOR, which is the op on the two compares.
+@end deftypefn
+
 @deftypefn {Target Hook} unsigned TARGET_LOOP_UNROLL_ADJUST (unsigned
@var{nunroll}, struct loop *@var{loop})
 This target hook returns a new value for the number of times @var{loop}
 should be unrolled. The parameter @var{nunroll} is the number of times
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index dd72b98..e49f8f5 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -8107,6 +8107,10 @@  build_type_attribute_variant (@var{mdecl},

 @hook TARGET_HAVE_CONDITIONAL_EXECUTION

+@hook TARGET_GEN_CCMP_FIRST
+
+@hook TARGET_GEN_CCMP_NEXT
+
 @hook TARGET_LOOP_UNROLL_ADJUST

 @defmac POWI_MAX_MULTS
diff --git a/gcc/target.def b/gcc/target.def
index e455211..6bbb907 100644
--- a/gcc/target.def
+++ b/gcc/target.def
@@ -2320,6 +2320,27 @@  modes and they have different conditional
execution capability, such as ARM.",
  bool, (void),
  default_have_conditional_execution)

+DEFHOOK
+(gen_ccmp_first,
+ "This function emits a comparison insn for the first of a sequence of\n\
+ conditional comparisions.  It returns a comparison expression appropriate\n\
+ for passing to @code{gen_ccmp_next} or to @code{cbranch_optab}.\n\
+ @code{unsignedp} is used when converting @code{op0} and @code{op1}'s mode.",
+ rtx, (int code, rtx op0, rtx op1),
+ NULL)
+
+DEFHOOK
+(gen_ccmp_next,
+ "This function emits a conditional comparison within a sequence of\n\
+ conditional comparisons.  The @code{prev} expression is the result of a\n\:q
+ prior call to @code{gen_ccmp_first} or @code{gen_ccmp_next}.  It may return\n\
+ @code{NULL} if the combination of @code{prev} and this comparison is\n\
+ not supported, otherwise the result must be appropriate for passing to\n\
+ @code{gen_ccmp_next} or @code{cbranch_optab}.  @code{bit_code}\n\
+ is AND or IOR, which is the op on the two compares.",
+ rtx, (rtx prev, int cmp_code, rtx op0, rtx op1, int bit_code),
+ NULL)
+
 /* Return a new value for loop unroll size.  */
 DEFHOOK