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author | Paul Koning <ni1d@arrl.net> | 2018-07-11 15:08:16 -0400 |
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committer | Paul Koning <pkoning@gcc.gnu.org> | 2018-07-11 15:08:16 -0400 |
commit | 8245edf3c1d4996d47974188332846a9c250b2de (patch) | |
tree | 94409ddfe49120bb6dc57560ebf635adf3deda72 /gcc | |
parent | bf8218dbef82171f9e370d23cce6b6e4f4e1c3bb (diff) | |
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md.texi (define_subst): Document how multiple occurrences of the same argument in the replacement...
* doc/md.texi (define_subst): Document how multiple occurrences of
the same argument in the replacement pattern are handled.
From-SVN: r262562
Diffstat (limited to 'gcc')
-rw-r--r-- | gcc/ChangeLog | 5 | ||||
-rw-r--r-- | gcc/doc/md.texi | 6 |
2 files changed, 10 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index cebe2bc..1d27aca 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2018-07-08 Paul Koning <ni1d@arrl.net> + + * doc/md.texi (define_subst): Document how multiple occurrences of + the same argument in the replacement pattern are handled. + 2018-07-11 Paul Koning <ni1d@arrl.net> * doc/extend.texi (Common Variable Attributes): Move "mode" into diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi index 6d15d99..c6bf77e 100644 --- a/gcc/doc/md.texi +++ b/gcc/doc/md.texi @@ -10263,7 +10263,11 @@ the expression from the original pattern, which matched @code{match_operand N} from the input pattern. As a consequence, @code{match_dup} cannot be used to point to @code{match_operand}s from the output pattern, it should always refer to a @code{match_operand} -from the input pattern. +from the input pattern. If a @code{match_dup N} occurs more than once +in the output template, its first occurrence is replaced with the +expression from the original pattern, and the subsequent expressions +are replaced with @code{match_dup N}, i.e., a reference to the first +expression. In the output template one can refer to the expressions from the original pattern and create new ones. For instance, some operands could |