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rtl.texi (COMPARE): Clarify documentation and reference section on comparisons.

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* rtl.texi (COMPARE): Clarify documentation and reference section
	on comparisons.

From-SVN: r40681
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Richard Kenner 2001-03-21 01:14:20 +00:00 • committed by Richard Kenner
parent ddd705d182
commit e26b89960c
2 changed files with 19 additions and 8 deletions
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@ -1,3 +1,8 @@
Tue Mar 20 20:15:06 2001 Richard Kenner <kenner@vlsi1.ultra.nyu.edu>
* rtl.texi (COMPARE): Clarify documentation and reference section
on comparisons.
2001-03-20 Stan Shebs <shebs@apple.com>
* objc/objc-act.c (get_static_reference): Use NULL_TREE.

22
gcc/rtl.texi
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@ -1412,15 +1412,21 @@ of comparison. The result is computed without overflow, as if with
infinite precision.
Of course, machines can't really subtract with infinite precision.
However, they can pretend to do so when only the sign of the
result will be used, which is the case when the result is stored
in the condition code. And that is the only way this kind of expression
may validly be used: as a value to be stored in the condition codes.
However, they can pretend to do so when only the sign of the result will
be used, which is the case when the result is stored in the condition
code. And that is the @emph{only} way this kind of expression may
validly be used: as a value to be stored in the condition codes, either
@code{(cc0)} or a register. @xref{Comparisons}.
The mode @var{m} is not related to the modes of @var{x} and @var{y},
but instead is the mode of the condition code value. If @code{(cc0)}
is used, it is @code{VOIDmode}. Otherwise it is some mode in class
@code{MODE_CC}, often @code{CCmode}. @xref{Condition Code}.
The mode @var{m} is not related to the modes of @var{x} and @var{y}, but
instead is the mode of the condition code value. If @code{(cc0)} is
used, it is @code{VOIDmode}. Otherwise it is some mode in class
@code{MODE_CC}, often @code{CCmode}. @xref{Condition Code}. If @var{m}
is @code{VOIDmode} or @code{CCmode}, the operation returns sufficient
information (in an unspecified format) so that any comparison operator
can be applied to the result of the @code{COMPARE} operation. For other
modes in class @code{MODE_CC}, the operation only returns a subset of
this information.
Normally, @var{x} and @var{y} must have the same mode. Otherwise,
@code{compare} is valid only if the mode of @var{x} is in class