* Re: [Emacs-diffs] master 74a5a33: Support native image transforms on MS-Windows
[not found] ` <20190629115506.BDED9208EA@vcs0.savannah.gnu.org>
@ 2019-06-29 19:21 ` Ken Brown
2019-06-30 0:00 ` Paul Eggert
0 siblings, 1 reply; 5+ messages in thread
From: Ken Brown @ 2019-06-29 19:21 UTC (permalink / raw)
To: emacs-devel@gnu.org, Eli Zaretskii
On 6/29/2019 7:55 AM, Eli Zaretskii wrote:
> branch: master
> commit 74a5a332fee8a346cf65ed6656c1b08dc1df5fde
> Author: Eli Zaretskii <eliz@gnu.org>
> Commit: Eli Zaretskii <eliz@gnu.org>
>
> Support native image transforms on MS-Windows
I'm seeing a few compiler warnings after this commit with GCC-7.4.0:
In file included from ../../master/src/image.c:37:0:
../../master/src/image.c: In function ‘image_set_transform’:
../../master/src/lisp.h:61:24: warning: implicit conversion from ‘float’ to
‘double’ to match other operand of binary expression [-Wdouble-promotion]
#define max(a, b) ((a) > (b) ? (a) : (b))
^
../../master/src/image.c:2123:12: note: in expansion of macro ‘max’
xscale = max (xscale, FLT_MIN);
^
../../master/src/lisp.h:61:36: warning: implicit conversion from ‘float’ to
‘double’ to match other result of conditional [-Wdouble-promotion]
#define max(a, b) ((a) > (b) ? (a) : (b))
^
../../master/src/image.c:2123:12: note: in expansion of macro ‘max’
xscale = max (xscale, FLT_MIN);
^
../../master/src/image.c: In function ‘image_set_transform.isra.21’:
../../master/src/image.c:2136:14: warning: ‘sin_r’ may be used uninitialized in
this function [-Wmaybe-uninitialized]
int cos_r, sin_r;
^~~~~
../../master/src/image.c:2175:17: warning: ‘cos_r’ may be used uninitialized in
this function [-Wmaybe-uninitialized]
matrix3x3 rot = { [0][0] = cos_r, [0][1] = -sin_r,
The double-promotion warning is fixed by using DBL_MIN instead of FLT_MIN.
The maybe-uninitialized warnings seem bogus to me.
Ken
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Emacs-diffs] master 74a5a33: Support native image transforms on MS-Windows
2019-06-29 19:21 ` [Emacs-diffs] master 74a5a33: Support native image transforms on MS-Windows Ken Brown
@ 2019-06-30 0:00 ` Paul Eggert
2019-06-30 2:39 ` Eli Zaretskii
0 siblings, 1 reply; 5+ messages in thread
From: Paul Eggert @ 2019-06-30 0:00 UTC (permalink / raw)
To: Ken Brown, emacs-devel@gnu.org, Eli Zaretskii
Ken Brown wrote:
> I'm seeing a few compiler warnings after this commit with GCC-7.4.0:
I installed a fix for that on master.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Emacs-diffs] master 74a5a33: Support native image transforms on MS-Windows
2019-06-30 0:00 ` Paul Eggert
@ 2019-06-30 2:39 ` Eli Zaretskii
2019-06-30 4:08 ` Paul Eggert
0 siblings, 1 reply; 5+ messages in thread
From: Eli Zaretskii @ 2019-06-30 2:39 UTC (permalink / raw)
To: Paul Eggert; +Cc: kbrown, emacs-devel
> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Sat, 29 Jun 2019 17:00:59 -0700
>
> Ken Brown wrote:
> > I'm seeing a few compiler warnings after this commit with GCC-7.4.0:
>
> I installed a fix for that on master.
Thanks, but I think divide_double part obfuscates the code for no good
reason.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Emacs-diffs] master 74a5a33: Support native image transforms on MS-Windows
2019-06-30 2:39 ` Eli Zaretskii
@ 2019-06-30 4:08 ` Paul Eggert
2019-06-30 14:21 ` Eli Zaretskii
0 siblings, 1 reply; 5+ messages in thread
From: Paul Eggert @ 2019-06-30 4:08 UTC (permalink / raw)
To: Eli Zaretskii; +Cc: kbrown, emacs-devel
Eli Zaretskii wrote:
> divide_double part obfuscates the code for no good reason.
I'm sure we can clear it up. It replaces the check against FLT_MIN, which to my
mind was even more obscure as there are no 'float' values in sight.
What is the failure scenario here? Is it not floating-point division by zero?
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Emacs-diffs] master 74a5a33: Support native image transforms on MS-Windows
2019-06-30 4:08 ` Paul Eggert
@ 2019-06-30 14:21 ` Eli Zaretskii
0 siblings, 0 replies; 5+ messages in thread
From: Eli Zaretskii @ 2019-06-30 14:21 UTC (permalink / raw)
To: Paul Eggert; +Cc: kbrown, emacs-devel
> Cc: kbrown@cornell.edu, emacs-devel@gnu.org
> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Sat, 29 Jun 2019 21:08:46 -0700
>
> Eli Zaretskii wrote:
> > divide_double part obfuscates the code for no good reason.
>
> I'm sure we can clear it up. It replaces the check against FLT_MIN, which to my
> mind was even more obscure as there are no 'float' values in sight.
I mean that an explicit division together with a test is more clear
than a call to a function that one needs to look up.
> What is the failure scenario here? Is it not floating-point division by zero?
Yes. But in one of the branches that is extremely unlikely, since the
denominator comes from the size of an image that we loaded.
^ permalink raw reply [flat|nested] 5+ messages in thread
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[not found] ` <20190629115506.BDED9208EA@vcs0.savannah.gnu.org>
2019-06-29 19:21 ` [Emacs-diffs] master 74a5a33: Support native image transforms on MS-Windows Ken Brown
2019-06-30 0:00 ` Paul Eggert
2019-06-30 2:39 ` Eli Zaretskii
2019-06-30 4:08 ` Paul Eggert
2019-06-30 14:21 ` Eli Zaretskii
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