From: Hans-Peter Nilsson <hp@axis.com>
To: <gcc-patches@gcc.gnu.org>, <hubicka@ucw.cz>
Subject: [PATCH] doc: md.texi (Insn Splitting): Tweak wording for readability.
Date: Tue, 14 Mar 2023 02:25:36 +0100 [thread overview]
Message-ID: <20230314012536.2789120417@pchp3.se.axis.com> (raw)
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.
---
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..786365143179 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, several
+restrictions apply.
+
+Splitting of a jump instruction into a sequence that has another jump
+instruction 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 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.
@findex define_insn_and_split
For the common case where the pattern of a define_split exactly matches the
--
2.30.2
next reply other threads:[~2023-03-14 1:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-14 1:25 Hans-Peter Nilsson [this message]
2023-03-14 4:31 ` Sandra Loosemore
2023-03-14 16:04 ` [PATCH v2] " Hans-Peter Nilsson
2023-03-14 16:43 ` Sandra Loosemore
2023-03-21 14:22 ` Hans-Peter Nilsson
2023-04-03 5:25 ` Jeff Law
2023-03-28 13:29 ` Ping #2: " Hans-Peter Nilsson
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