[Bug tree-optimization/71433] New: [7 Regression] -Warray-bounds false positive with -O2

[vincent-gcc at vinc17 dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71433

            Bug ID: 71433
           Summary: [7 Regression] -Warray-bounds false positive with -O2
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vincent-gcc at vinc17 dot net
  Target Milestone: ---

When compiling GNU MPFR 3.1.4 with CFLAGS="-O2 -Werror=array-bounds" and

gcc (Debian 20160603-1) 7.0.0 20160603 (experimental) [trunk revision 237077]

I get:

get_d.c: In function 'mpfr_get_d':
get_d.c:115:24: error: array subscript is above array bounds
[-Werror=array-bounds]
             d = (d + tp[i]) / MP_BASE_AS_DOUBLE;
                      ~~^~~

There was no such problem with

gcc (Debian 20160508-1) 7.0.0 20160508 (experimental) [trunk revision 236009]

so that's a recent regression.