[Bug tree-optimization/63302] [4.9 Regression] Code with 64-bit long long constants is miscompiled on 32-bit host

[zhenqiang.chen at arm dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63302

--- Comment #10 from Zhenqiang Chen <zhenqiang.chen at arm dot com> ---
(In reply to dave.anglin from comment #8)
> On 28-Sep-14, at 10:34 AM, dave.anglin at bell dot net wrote:
> 
> > This is what I see on the trunk, but 4.9 is wrong.  Possibly, there is
> > a transformation
> > after optimize_range_tests_diff where things go wrong on 4.9.
> 
> It seems the difference actually occurs in reassoc1.
> 
> 4.9:
> 
>    <bb 2>:
>    x_2 = ival_1(D) & -2147481601;
>    _3 = x_2 == 0;
>    _8 = x_2 & 2147483647;
>    _9 = _8 == 0;
>    _4 = x_2 == -2147483648;
>    _5 = _9;
>    _6 = (int) _5;
>    return _6;

This is not optimized by my patch: optimize_range_tests_diff

> trunk:
> 
>    <bb 2>:
>    x_2 = ival_1(D) & -2147481601;
>    _3 = x_2 == 0;
>    _8 = x_2 + 2147483648;
>    _9 = _8 & -2147483649;
>    _10 = _9 == 0;
>    _4 = x_2 == -2147483648;
>    _5 = _10;
>    _6 = (int) _5;
>    return _6;

This is optimized by the patch. optimize_range_tests_diff is the only change I
added for the patch. Others were just reorganization.

Can you show more detail dumps with -fdump-tree-reassoc1-details?

Thanks!
-Zhenqiang