[Bug target/79242] ICE in simplify_subreg, at simplify-rtx.c:6029

[stilor at att dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79242

Alexey Neyman <stilor at att dot net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |stilor at att dot net

--- Comment #4 from Alexey Neyman <stilor at att dot net> ---
Seeing this issue with a test case as simple as:

int
reallocarray(unsigned __int20 a, unsigned __int20 b)
{
 return 0xfffffUL / a < b;
}

This is a regression in GCC7/GCC8, GCC6 compiles it successfully. Started with
the following commit:

Author: amonakov <amonakov@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Mon May 30 14:37:02 2016 +0000

    match.pd: optimize unsigned mul overflow check

    gcc/
    2016-05-28  Alexander Monakov  <amonakov@ispras.ru>
                Marc Glisse  <marc.glisse@inria.fr>

            PR tree-optimization/71289
            * match.pd (-1 / B < A, A > -1 / B): New transformations.

    gcc/testsuite/
    2016-05-28  Alexander Monakov  <amonakov@ispras.ru>

            PR tree-optimization/71289
            * gcc.dg/pr71289.c: New test.



    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@236882
138bc75d-0d04-0410-961f-82ee72b054a4