[Bug rtl-optimization/88596] New: [9 Regression] ICE: Maximum number of LRA assignment passes is achieved (30)

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88596

            Bug ID: 88596
           Summary: [9 Regression] ICE: Maximum number of LRA assignment
                    passes is achieved (30)
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code, ra
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---
            Target: x86_64-unknown-linux-gnu

gcc-9.0.0-alpha20181223 snapshot (r267388) ICEs when compiling the following
snippet at any optimization level except -Os and w/ -fschedule-insns
-fselective-scheduling --param selsched-max-lookahead=78:

struct {
  _Complex char ka;
} t6, n3, cf, uq, w9;

void
r9 ();

void
he ();

void
b3 ();

void
px (void)
{
  r9 (t6, t6, n3, t6, n3, cf);
  r9 (t6, t6, n3, n3, cf, cf);
  r9 (t6, t6, n3, n3, cf, uq);
  r9 (t6, t6, n3, n3, cf, cf);
  r9 (t6, n3, t6, cf, uq, w9);
  he (t6, t6, t6, t6);
  he (t6, t6, t6, t6);
  he (t6, t6, t6, t6);
  b3 (t6, t6, t6, t6, t6);
}

% x86_64-unknown-linux-gnu-gcc-9.0.0-alpha20181223 -O1 -fschedule-insns
-fselective-scheduling --param selsched-max-lookahead=78 -c a76zvftd.c
during RTL pass: reload
a76zvftd.c: In function 'px':
a76zvftd.c:26:1: internal compiler error: Maximum number of LRA assignment
passes is achieved (30)

   26 | }
      | ^
0xb8ec17 lra_assign(bool&)
       
/var/tmp/portage/sys-devel/gcc-9.0.0_alpha20181223/work/gcc-9-20181223/gcc/lra-assigns.c:1672
0xb897ad lra(_IO_FILE*)
       
/var/tmp/portage/sys-devel/gcc-9.0.0_alpha20181223/work/gcc-9-20181223/gcc/lra.c:2520
0xb40a19 do_reload
       
/var/tmp/portage/sys-devel/gcc-9.0.0_alpha20181223/work/gcc-9-20181223/gcc/ira.c:5475
0xb40a19 execute
       
/var/tmp/portage/sys-devel/gcc-9.0.0_alpha20181223/work/gcc-9-20181223/gcc/ira.c:5659