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.
