From: Jeff Law <law@redhat.com>
To: David Malcolm <dmalcolm@redhat.com>, gcc-patches@gcc.gnu.org
Subject: Re: [PATCH 1/2] libcpp: Avoid unnecessary ad-hoc uses for large source files
Date: Mon, 21 Dec 2015 20:10:00 -0000 [thread overview]
Message-ID: <56785CB0.7000808@redhat.com> (raw)
In-Reply-To: <1450470070-31069-1-git-send-email-dmalcolm@redhat.com>
On 12/18/2015 01:21 PM, David Malcolm wrote:
> When debugging PR c++/68819 I noticed an inefficiency during
> the handling of locations > LINE_MAP_MAX_LOCATION_WITH_COLS.
> When combining ranges for locations with
> start == caret == finish (with a NULL data ptr)
> get_combined_adhoc_loc was always building an ad-hoc entry
> rather than simply returning the location.
>
> Normally can_be_stored_compactly_p returns true for such triples,
> but it returns false for locations above
> LINE_MAP_MAX_LOCATION_WITH_COLS (as the range-packing code isn't
> designed to handle the latter). There's a followup test within
> get_combined_adhoc_loc for detecting the start == caret == finish
> case, but I'd conditionalized it on the location being one of the
> two reserved locations:
> locus < RESERVED_LOCATION_COUNT
>
> That condition has been there since I introduced range-packing
> (as part ofr230331). I believe at the time I didn't realize there
> was any other way for such a location triple to fail
> can_be_stored_compactly_p.
>
> These location triples occur a lot where we're in this mode:
> every token, and every expression that fits on one line,
> so this is wasteful.
>
> Removing the locus < RESERVED_LOCATION_COUNT part of the
> condition allows us to avoid using the ad-hoc table for these
> cases.
>
> Successfully bootstrapped®rtested on x86_64-pc-linux-gnu
> in combination with the following patch.
>
> libcpp/ChangeLog:
> * line-map.c (get_combined_adhoc_loc): Remove condition
> on locus < RESERVED_LOCATION_COUNT when considering
> whether a caret == start == finish location can be
> simply stored as the caret location.
OK.
jeff
prev parent reply other threads:[~2015-12-21 20:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-18 20:01 David Malcolm
2015-12-18 20:01 ` [PATCH 2/2] PR c++/68819: libcpp fallbacks and -Wmisleading-indentation David Malcolm
2015-12-21 21:10 ` Jeff Law
2015-12-21 21:20 ` Jakub Jelinek
2016-01-06 20:02 ` David Malcolm
2016-01-07 8:41 ` Jakub Jelinek
2016-01-06 19:54 ` David Malcolm
2016-01-08 21:20 ` [PATCH] PR preprocessor/69177 and PR c++/68819: libcpp fallbacks and -Wmisleading-indentation (v2) David Malcolm
2016-01-14 18:50 ` Jeff Law
2015-12-21 20:10 ` Jeff Law [this message]
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