[PATCH] Optimize out a call to PerlIO_get_cnt in pp_fttext

[p5pRT]

Migrated from rt.perl.org#121489 (status was 'resolved')

Searchable as RT121489$

[p5pRT]

From @nthykier

Created by @nthykier

Perl Info

Flags:
    category=core
    severity=wishlist
    Type=Patch
    PatchStatus=HasPatch

Site configuration information for perl 5.19.11:

Configured by Niels Thykier at Sat Mar 22 15:13:03 UTC 2014.

Summary of my perl5 (revision 5 version 19 subversion 11) configuration:
  Derived from: 
  Platform:
    osname=linux, osvers=3.13-1-amd64, archname=x86_64-linux
    uname='linux mangetsu 3.13-1-amd64 #1 smp debian 3.13.5-1 (2014-03-04) x86_64 gnulinux '
    config_args='-des -Dusedevel'
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=undef, usemultiplicity=undef
    use64bitint=define, use64bitall=define, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    optimize='-O2',
    cppflags='-fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
    ccversion='', gccversion='4.8.2', gccosandvers=''
    intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
    ivtype='long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -fstack-protector -L/usr/local/lib'
    libpth=/usr/local/lib /usr/lib/gcc/x86_64-linux-gnu/4.8/include-fixed /usr/include/x86_64-linux-gnu /usr/lib /lib/x86_64-linux-gnu /lib/../lib /usr/lib/x86_64-linux-gnu /usr/lib/../lib /lib
    libs=-lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lc -lgdbm_compat
    perllibs=-lnsl -ldl -lm -lcrypt -lutil -lc
    libc=libc-2.18.so, so=so, useshrplib=false, libperl=libperl.a
    gnulibc_version='2.18'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
    cccdlflags='-fPIC', lddlflags='-shared -O2 -L/usr/local/lib -fstack-protector'

Locally applied patches:
    uncommitted-changes


@INC for perl 5.19.11:
    lib
    /usr/local/lib/perl5/site_perl/5.19.11/x86_64-linux
    /usr/local/lib/perl5/site_perl/5.19.11
    /usr/local/lib/perl5/5.19.11/x86_64-linux
    /usr/local/lib/perl5/5.19.11
    .


Environment for perl 5.19.11:
    LANG=C
    LANGUAGE=en_GB:en
    LC_ALL=C
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games
    PERL_BADLANG (unset)
    SHELL=/bin/bash

[p5pRT]

From @nthykier

0001-pp_sys.c-Optimize-out-a-call-to-PerlIO_get_cnt.patch

From f7894fadda3f53bccbfb9beb64476389311253c8 Mon Sep 17 00:00:00 2001
From: Niels Thykier <niels@thykier.net>
Date: Sat, 22 Mar 2014 15:54:41 +0100
Subject: [PATCH] pp_sys.c: Optimize out a call to PerlIO_get_cnt

If PerlIO_getc returns EOF, PerlIO_get_cnt is not going to return a
positive value all of a sudden.

Signed-off-by: Niels Thykier <niels@thykier.net>
---
 pp_sys.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/pp_sys.c b/pp_sys.c
index 9f97177..07a0941 100644
--- a/pp_sys.c
+++ b/pp_sys.c
@@ -3322,9 +3322,10 @@ PP(pp_fttext)
 		i = PerlIO_getc(IoIFP(io));
 		if (i != EOF)
 		    (void)PerlIO_ungetc(IoIFP(io),i);
+                else
+                    /* null file is anything */
+                    FT_RETURNYES;
 	    }
-	    if (PerlIO_get_cnt(IoIFP(io)) <= 0)	/* null file is anything */
-		FT_RETURNYES;
 	    len = PerlIO_get_bufsiz(IoIFP(io));
 	    s = (STDCHAR *) PerlIO_get_base(IoIFP(io));
 	    /* sfio can have large buffers - limit to 512 */
-- 
1.9.0

[p5pRT]

From @khwilliamson

On 03/22/2014 09​:51 AM, niels@​thykier.net (via RT) wrote​:

# New Ticket Created by niels@​thykier.net
# Please include the string​: [perl #121489]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl5/Ticket/Display.html?id=121489 >

This is a bug report for perl from niels@​thykier.net,
generated with the help of perlbug 1.40 running under perl 5.19.11.

Thanks!

I will apply this in 5.21 after the code base reopens for general
patches, unless there is objection in the meantime

[p5pRT]

The RT System itself - Status changed from 'new' to 'open'

[p5pRT]

From @nwc10

On Sat, Mar 22, 2014 at 11​:47​:01AM -0600, Karl Williamson wrote​:

On 03/22/2014 09​:51 AM, niels@​thykier.net (via RT) wrote​:

This is a bug report for perl from niels@​thykier.net,
generated with the help of perlbug 1.40 running under perl 5.19.11.

Thanks!

I will apply this in 5.21 after the code base reopens for general
patches, unless there is objection in the meantime

I added it to the "5.21.1 blockers ticket"
https://rt-archive.perl.org/perl5/Ticket/Display.html?id=121332
on the assumption that the purpose of that ticket is to avoid forgetting
things like this.

Nicholas Clark

[p5pRT]

From @nthykier

On 2014-03-22 18​:46, karl williamson via RT wrote​:

On 03/22/2014 09​:51 AM, niels@​thykier.net (via RT) wrote​:

# New Ticket Created by niels@​thykier.net
# Please include the string​: [perl #121489]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl5/Ticket/Display.html?id=121489 >

This is a bug report for perl from niels@​thykier.net,
generated with the help of perlbug 1.40 running under perl 5.19.11.

Thanks!

I will apply this in 5.21 after the code base reopens for general
patches, unless there is objection in the meantime

Thanks, looking forward to it. :)

~Niels

[p5pRT]

From @tonycoz

On Sat Mar 22 08​:51​:25 2014, niels@​thykier.net wrote​:

This is a bug report for perl from niels@​thykier.net,
generated with the help of perlbug 1.40 running under perl 5.19.11.

Thanks, applied as bd47baf.

Tony

[p5pRT]

@tonycoz - Status changed from 'open' to 'resolved'