[Bug c++/101634] New: Vectorize optimisations trigger floating point exception

[Bug c++/101634] New: Vectorize optimisations trigger floating point exception

[gcc at wdqb dot uk]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101634

            Bug ID: 101634
           Summary: Vectorize optimisations trigger floating point
                    exception
           Product: gcc
           Version: 11.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gcc at wdqb dot uk
  Target Milestone: ---

Created attachment 51208
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51208&action=edit
Code that reproduces the issue

I am using g++ 11.1.1 on OpenSUSE Tumbleweed 20210713.

When compiled with `g++ -O3 example.cpp` the code snippet triggers a floating
point exception and the program exits through the `signalHandler` function. I
believe this behaviour to be incorrect.

When compiled with `g++ -O3 -fno-tree-slp-vectorize example.cpp` (or any lower
level of optimisation) the exception is not triggered and the program exits
normally.

When compiled with any older version of `g++` with `O3` the exception is not
triggered and the program exits normally.

The program can also be modified to read it's input values from a file (see
commented section). This is shown to prove that the optimisation is not
dependent on the values being available at compile time. Indeed, this is a
snippet of a larger program in which the values are read in from a file.

[Bug tree-optimization/101634] Vectorize optimisations trigger floating point exception

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101634

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |DUPLICATE

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
I believe the issue has been fixed already and is a duplicate of PR100778. 
There's an updated GCC 11 package pending in
https://build.opensuse.org/project/show/openSUSE:Factory:Staging:A which you
could verify against (or in devel:gcc which should even be published).

A locally built g++ from the GCC 11 branch doesn't reproduce the issue for me.

*** This bug has been marked as a duplicate of bug 100778 ***

[Bug tree-optimization/101634] Vectorize optimisations trigger floating point exception

[gcc at wdqb dot uk]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101634

William Bainbridge <gcc at wdqb dot uk> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|DUPLICATE                   |FIXED

--- Comment #2 from William Bainbridge <gcc at wdqb dot uk> ---
Thank you for looking into it. I have verified that gcc-11.2-RC-20210721 fixes
the issue.

[Bug tree-optimization/101634] Vectorize optimisations trigger floating point exception

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101634

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|FIXED                       |DUPLICATE

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---


*** This bug has been marked as a duplicate of bug 100778 ***