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Re: [PATCH] add split condition to *fix_trunchi_1


Zack Weinberg wrote:

- ""
+ "&& 1"



Aren't these functionally identical? If not, why not?


This text is from gccint.info, "Insn Splitting" chapter:

  For the common case where the pattern of a define_split exactly
matches the pattern of a define_insn, use `define_insn_and_split'.  It
looks like this:

    (define_insn_and_split
      [INSN-PATTERN]
      "CONDITION"
      "OUTPUT-TEMPLATE"
      "SPLIT-CONDITION"
      [NEW-INSN-PATTERN-1
       NEW-INSN-PATTERN-2
       ...]
      "PREPARATION-STATEMENTS"
      [INSN-ATTRIBUTES])

  INSN-PATTERN, CONDITION, OUTPUT-TEMPLATE, and INSN-ATTRIBUTES are
used as in `define_insn'.  The NEW-INSN-PATTERN vector and the
PREPARATION-STATEMENTS are used as in a `define_split'.  The
SPLIT-CONDITION is also used as in `define_split', with the additional
behavior that if the condition starts with `&&', the condition used for
the split will be the constructed as a logical "and" of the split
condition with the insn condition.  For example, from i386.md:
...

Uros.


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