Re: [PATCH 4/4] useless-if-before-free: skip non-matching lines early

[Ján Tomko]

On Mon, Aug 01, 2016 at 10:56:15AM -0700, Jim Meyering wrote:
> On Mon, Aug 1, 2016 at 5:11 AM, Ján Tomko <address@hidden> wrote:
> > 1.44s to 1.02s
>
> Thanks. Mentioned that in the commit log.
> Here is the proposed patch:

> From 3238fa6a54927c1af81dbd2c512f5e6ead8dcfc2 Mon Sep 17 00:00:00 2001
> From: =?UTF-8?q?J=C3=A1n=20Tomko?= <address@hidden>
> Date: Mon, 1 Aug 2016 10:54:47 -0700
> Subject: [PATCH] useless-if-before-free: skip non-matching lines early
>
> * build-aux/useless-if-before-free: First match each line with the
> simple/quick /\bif\b/ and reject if there is no match. This often
> saves the cost of the much more involved regular expression.
> For libvirt, this decreases the cost from 1.44s to 1.02s.
> ---
> ChangeLog                        | 8 ++++++++
> build-aux/useless-if-before-free | 5 ++++-
> 2 files changed, 12 insertions(+), 1 deletion(-)

Looks good to me,

> diff --git a/ChangeLog b/ChangeLog
> index 28327f2..8e8ba77 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,5 +1,13 @@
> 2016-07-26  Ján Tomko  <address@hidden>
>
> +       useless-if-before-free: skip non-matching lines early
> +       * build-aux/useless-if-before-free: First match each line with the
> +       simple/quick /\bif\b/ and reject if there is no match. This often
> +       saves the cost of the much more involved regular expression.
> +       For libvirt, this decreases the cost from 1.44s to 1.02s.
> +
> +2016-07-26  Ján Tomko  <address@hidden>
> +
>         maint.mk: speed up sc_po_check
>         sc_po_check would skip files based on their names, or on the
>         existence of files with derived names. Rewrite it to use perl

however this context hunk is from commit
5fb8cef6494aca3108e9d8644395b948720e77ba
   maint.mk: speed up sc_po_check
which contains nothing else but the ChangeLog entry duplicated from:
04fd8821111d3af23e8485f0f78b60f42babda1d
   maint.mk: speed up sc_po_check

Jan

> diff --git a/build-aux/useless-if-before-free b/build-aux/useless-if-before-free
> index 1899b1f..d7a8c0d 100755
> --- a/build-aux/useless-if-before-free
> +++ b/build-aux/useless-if-before-free
> @@ -4,7 +4,7 @@ eval '(exit $?0)' && eval 'exec perl -wST "$0" "$@"'
> # Detect instances of "if (p) free (p);".
> # Likewise "if (p != 0)", "if (0 != p)", or with NULL; and with braces.
>
> -my $VERSION = '2016-01-12 23:13'; # UTC
> +my $VERSION = '2016-08-01 17:47'; # UTC
> # The definition above must lie within the first 8 lines in order
> # for the Emacs time-stamp write hook (at end) to update it.
> # If you change this file with Emacs, please let the write hook
> @@ -129,6 +129,9 @@ sub is_NULL ($)
>           $err = EXIT_ERROR, next;
>       while (defined (my $line = <FH>))
>         {
> +          # Skip non-matching lines early to save time
> +          $line =~ /\bif\b/
> +            or next;
>           while ($line =~
>               /\b(if\s*\(\s*([^)]+?)(?:\s*!=\s*([^)]+?))?\s*\)
>               #  1          2                  3
> --
> 2.8.0-rc2

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