[Bug tree-optimization/108430] New: [13 Regression] Wrong code with -msve-vector-bits=512 since r13-707-g68e0063397

[acoplan at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108430

            Bug ID: 108430
           Summary: [13 Regression] Wrong code with -msve-vector-bits=512
                    since r13-707-g68e0063397
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: acoplan at gcc dot gnu.org
  Target Milestone: ---

For the following testcase:

static long d;
static int i = 37;
static unsigned long a[22];
static unsigned short c[22];
static unsigned g[80];
static unsigned short *h = c;
static unsigned long *j = a;
int main() {
  for (long m = 0; m < 8; ++m)
    d = 1;
  for (unsigned char p = 0; p < 17; p += (d ? i : 0) - 35)
  {
    long t = h[p] ? i : j[p];
    g[p] = t;
  }
  if (g[0])
    __builtin_abort ();
}

we appear to miscompile it with -O3 -march=armv8.2-a+sve -msve-vector-bits=512
since r13-707-g68e0063397ba820e71adc220b2da0581dce29ffa :


commit 68e0063397ba820e71adc220b2da0581dce29ffa (HEAD, refs/bisect/bad)         
Author: Richard Biener <rguent...@suse.de>                                      
Date:   Mon Apr 11 12:36:53 2022                                                

    Force the selection operand of a GIMPLE COND_EXPR to be a register