Is there an error in GCC Internals Manual, chapter 16.4?
Chapter 16.4, "RTL Template" in GCC Internals Manual, found at https://gcc.gnu.org/onlinedocs/gccint/RTL-Template.html#RTL-Template has this to say about match_scratch: " (match_scratch:m n constraint) This expression is also a placeholder for operand number n and indicates that operand must be a scratch or reg expression. When matching patterns, this is equivalent to (match_operand:m n "scratch_operand" pred) " I'm wondering what is "pred" in this context? I'm thinking that "scratch_operand" might be the predicate, so should there read "constraint" in place of "pred" in the last clause? I'm sorry if this is an idiotic question, I'm just trying to digest all the information, so I might be overly pedantic about the matter. I just want to be sure I understand what I read. I'm sure it'll all make sense when I actually need to use this expression. Sorry to have taken your time. -Panu
Re: Is there an error in GCC Internals Manual, chapter 16.4?
Panu-Kristian Poiksalo writes:
> Chapter 16.4, "RTL Template" in GCC Internals Manual, found at
> https://gcc.gnu.org/onlinedocs/gccint/RTL-Template.html#RTL-Template
> has this to say about match_scratch:
>
> "
> (match_scratch:m n constraint)
> This expression is also a placeholder for operand number n and
> indicates that operand must be a scratch or reg expression.
>
> When matching patterns, this is equivalent to
>
> (match_operand:m n "scratch_operand" pred)
> "
> I'm wondering what is "pred" in this context?
I think it is supposed to be "constraint". This error is already
present in the first revision of the file. I have installed this patch
in trunk as obvious. Thanks for the report.
Andreas.
* doc/md.texi (RTL Template) [match_scratch]: Correct equivalent
match_operand expression.
Index: doc/md.texi
===
--- doc/md.texi (revision 216440)
+++ doc/md.texi (working copy)
@@ -297,7 +297,7 @@
When matching patterns, this is equivalent to
@smallexample
-(match_operand:@var{m} @var{n} "scratch_operand" @var{pred})
+(match_operand:@var{m} @var{n} "scratch_operand" @var{constraint})
@end smallexample
but, when generating RTL, it produces a (@code{scratch}:@var{m})
--
Andreas Schwab, sch...@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
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