[Bug c++/86586] [7/8/9 Regression] -Wsign-compare affects code generation

2019-05-14 Thread sbergman at redhat dot com 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86586

Stephan Bergmann  changed:

   What|Removed |Added

 CC||sbergman at redhat dot com

--- Comment #10 from Stephan Bergmann  ---
(In reply to Jason Merrill from comment #8)
> Author: jason
> Date: Wed Apr  3 20:12:00 2019
> New Revision: 270136
> 
> URL: https://gcc.gnu.org/viewcvs?rev=270136=gcc=rev
> Log:
>   PR c++/86586 - -fcompare-debug=-Wsign-compare.
> 
> This patch limits constexpr folding for -Wsign-compare to only cases that we
> would warn for without considering constant values, avoiding the folding in
> the testcase in question.

Starting with that commit,

  constexpr int f() { return 0; }
  bool b = f() != 0xU;

now emits a -Wsign-compare, while the similar

  constexpr int f() { return 0; }
  constexpr int n = f();
  bool b = n != 0xU;

still does not.

I assume that is an unintended regression?

[Bug c++/86586] [7/8/9 Regression] -Wsign-compare affects code generation

2019-04-03 Thread jason at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86586

Jason Merrill  changed:

   What|Removed |Added

 Status|UNCONFIRMED |RESOLVED
 CC||jason at gcc dot gnu.org
 Resolution|--- |FIXED
   Assignee|unassigned at gcc dot gnu.org  |jason at gcc dot gnu.org
   Target Milestone|7.5 |9.0

--- Comment #9 from Jason Merrill  ---
Fixed for GCC 9 by not folding on this testcase.  This doesn't address the
general issue, but reduces its scope.  Not worth backporting.

[Bug c++/86586] [7/8/9 Regression] -Wsign-compare affects code generation

2019-04-03 Thread jason at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86586

--- Comment #8 from Jason Merrill  ---
Author: jason
Date: Wed Apr  3 20:12:00 2019
New Revision: 270136

URL: https://gcc.gnu.org/viewcvs?rev=270136=gcc=rev
Log:
PR c++/86586 - -fcompare-debug=-Wsign-compare.

This patch limits constexpr folding for -Wsign-compare to only cases that we
would warn for without considering constant values, avoiding the folding in
the testcase in question.

gcc/c-family/
* c-warn.c (warn_for_sign_compare): Call fold_for_warn.
gcc/cp/
* typeck.c (cp_build_binary_op): Don't fold for -Wsign-compare.

Modified:
trunk/gcc/c-family/ChangeLog
trunk/gcc/c-family/c-warn.c
trunk/gcc/cp/ChangeLog
trunk/gcc/cp/typeck.c
trunk/gcc/testsuite/g++.target/i386/mv1.C

[Bug c++/86586] [7/8/9 Regression] -Wsign-compare affects code generation

2018-12-06 Thread rguenth at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86586

Richard Biener  changed:

   What|Removed |Added

   Target Milestone|7.4 |7.5

[Bug c++/86586] [7/8/9 Regression] -Wsign-compare affects code generation

2018-11-22 Thread rguenth at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86586

Richard Biener  changed:

   What|Removed |Added

   Priority|P3  |P2

[Bug c++/86586] [7/8/9 Regression] -Wsign-compare affects code generation

2018-10-31 Thread rguenth at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86586

Richard Biener  changed:

   What|Removed |Added

   Target Milestone|--- |7.4