> Date: Mon, 13 Mar 2023 22:31:21 -0600
> From: Sandra Loosemore <san...@codesourcery.com>
> On 3/13/23 19:25, Hans-Peter Nilsson via Gcc-patches wrote:
> > Jan, did I get this right? This was from your
> > r0-36413-g6b24c25948265c / svn r44249, now on its 22nd year!
> >
> > I spot-checked the pdf for readability. Also calling on a
> > doc maintainer to check grammos etc. Ok to commit?
> >
> > -- >8 --
> > I needed to check what was allowed in a define_split, but
> > had problems understanding what was meant by "Splitting of
> > jump instruction into sequence that over by another jump
> > instruction".
> >
> > * doc/md.texi (Insn Splitting): Tweak wording for readability.
>
> Thanks for noticing this! I can't comment on technical correctness, but
> I do have some further suggestions on wording below.
Thank you for the review! Updated version below with your
suggestions. When spot-checking the pdf I noticed a strange
split of the page after the next after the section I
changed: last on page 484 "17.17 Including Patterns in
Machine Descriptions", there's a "(include" last on the page
and "pathname)" on top of page 485. I'm afraid this patch
triggered that. IMHO it'd be wrong to diddle with
formatting of *that* in *this* patch, instead leaving it to
a follow-up-patch. I think the obvious fix is to *not*
split up (include pathname)" because that just looks odd
even without the page end in-between. Right?
-- >8 --
I needed to check what was allowed in a define_split, but
had problems understanding what was meant by "Splitting of
jump instruction into sequence that over by another jump
instruction".
* doc/md.texi (Insn Splitting): Tweak wording for readability.
Co-Authored-By: Sandra Loosemore <san...@codesourcery.com>
---
gcc/doc/md.texi | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)
diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index 8e3113599fdc..134b227b9a93 100644
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -8756,21 +8756,21 @@ insns that don't. Instead, write two separate
@code{define_split}
definitions, one for the insns that are valid and one for the insns that
are not valid.
-The splitter is allowed to split jump instructions into sequence of
-jumps or create new jumps in while splitting non-jump instructions. As
-the control flow graph and branch prediction information needs to be updated,
-several restriction apply.
-
-Splitting of jump instruction into sequence that over by another jump
-instruction is always valid, as compiler expect identical behavior of new
-jump. When new sequence contains multiple jump instructions or new labels,
-more assistance is needed. Splitter is required to create only unconditional
-jumps, or simple conditional jump instructions. Additionally it must attach a
-@code{REG_BR_PROB} note to each conditional jump. A global variable
-@code{split_branch_probability} holds the probability of the original branch
in case
-it was a simple conditional jump, @minus{}1 otherwise. To simplify
-recomputing of edge frequencies, the new sequence is required to have only
-forward jumps to the newly created labels.
+The splitter is allowed to split jump instructions into a sequence of jumps or
+create new jumps while splitting non-jump instructions. As the control flow
+graph and branch prediction information needs to be updated after the splitter
+runs, several restrictions apply.
+
+Splitting of a jump instruction into a sequence that has another jump
+instruction to the same label is always valid, as the compiler expects
+identical behavior of the new jump. When the new sequence contains multiple
+jump instructions or new labels, more assistance is needed. The splitter is
+permitted to create only unconditional jumps, or simple conditional jump
+instructions. Additionally it must attach a @code{REG_BR_PROB} note to each
+conditional jump. A global variable @code{split_branch_probability} holds the
+probability of the original branch in case it was a simple conditional jump,
+@minus{}1 otherwise. To simplify recomputing of edge frequencies, the new
+sequence is permitted to have only forward jumps to the newly-created labels.
@findex define_insn_and_split
For the common case where the pattern of a define_split exactly matches the
--
2.30.2
brgds, H-P
