[Bug target/71873] New: ICE in push_reload

["saaadhu at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71873

            Bug ID: 71873
           Summary: ICE in push_reload
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: saaadhu at gcc dot gnu.org
  Target Milestone: ---

The following testcase causes an ICE in push_reload when compiled with 

$ cat test.c
#include <stdint.h>

typedef struct {
  uint8_t x;
  uint32_t y;
} A;

A a;

extern int bar(int);
extern int foo (char *s, ...);

extern uint8_t param;
extern uint8_t h,m,s,ld,lm;
extern uint16_t d;

void gps_parse_string(int z)
{
  while (bar(z))
  {
    switch (param)
    {
      case 0: foo("a", &h, &m, &s, &d); break;
      case 1: foo("d", &ld, &lm, &a.y); break;
    }
  }
}


$ avr-gcc -Os -mmcu=atmega8 -S test.c
test.c: In function 'gps_parse_string':
test.c:27:1: internal compiler error: in push_reload, at reload.c:1349
 }
 ^
0xd8feb0 push_reload(rtx_def*, rtx_def*, rtx_def**, rtx_def**, reg_class,
machine_mode, machine_mode, int, int, int, reload_type)
        /home/saaadhu/code/work/gcc/gcc/reload.c:1348
0xd8f760 push_reload(rtx_def*, rtx_def*, rtx_def**, rtx_def**, reg_class,
machine_mode, machine_mode, int, int, int, reload_type)
        /home/saaadhu/code/work/gcc/gcc/reload.c:1155
0xd97e86 find_reloads(rtx_insn*, int, int, int, short*)
        /home/saaadhu/code/work/gcc/gcc/reload.c:4035
0xda58d4 calculate_needs_all_insns
        /home/saaadhu/code/work/gcc/gcc/reload1.c:1483
0xda4018 reload(rtx_insn*, int)
        /home/saaadhu/code/work/gcc/gcc/reload1.c:995
0xc0865e do_reload
        /home/saaadhu/code/work/gcc/gcc/ira.c:5396
0xc08a46 execute
        /home/saaadhu/code/work/gcc/gcc/ira.c:5568
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.

Might be a duplicate of PR 67031, but the testcases there do not cause an ICE
on trunk (gcc version 7.0.0 20160704), but the above one does.