Re: [Ping] [PATCH, 1/10] two hooks for conditional compare (ccmp)

[Richard Henderson <rth at redhat dot com>]

On 09/22/2014 11:43 PM, Zhenqiang Chen wrote:
> 
> +@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
> +

This whole section should be removed.  You do not have a named ccmp pattern.
Even your example below is an *unnamed pattern.  This is an implementation
detail of the aarch64 backend.

Named patterns are used when that is the interface the middle-end uses to emit
code.  But you're not using named patterns, you're using:

> 
> +@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

Every place above where you refer to the arguments of the function should use
@var; you're using @code for most of them.  Use @code{AND} and @code{IOR}.


r~