Example: provenance_basic_global_xy.c

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    #include <stdio.h>
    #include <string.h> 
    int x=1, y=2;
    int main() {
      int *p = &x + 1;
      int *q = &y;
      printf("Addresses: p=%p q=%p\n",(void*)p,(void*)q);
      if (memcmp(&p, &q, sizeof(p)) == 0) {
        *p = 11;  // does this have undefined behaviour?
        printf("x=%d y=%d *p=%d *q=%d\n",x,y,*p,*q);
      }
    }
[link to run test in Cerberus]

Experimental data (what does this mean?) 



cerberus-concrete-PVI-plain Addresses: p=(@54, 0xfffff1ec) q=(@55, 0xfffff1e4)


cerberus-concrete-PVI-ae Addresses: p=(@54, 0xfffff1ec) q=(@55, 0xfffff1e4)


cerberus-concrete-PVI-ae-udi Addresses: p=(@54, 0xfffff1ec) q=(@55, 0xfffff1e4)


gcc-8.3-O0 Addresses: p=0x100001024 q=0x100001024
x=1 y=11 *p=11 *q=11


gcc-8.3-O2 Addresses: p=0x100001020 q=0x100001018


gcc-8.3-O3 Addresses: p=0x100001020 q=0x100001018


gcc-8.3-O2-no-strict-aliasing Addresses: p=0x100001020 q=0x100001018


gcc-8.3-O3-no-strict-aliasing Addresses: p=0x100001020 q=0x100001018


clang-7.0.1-O0 Addresses: p=0x10000101c q=0x10000101c
x=1 y=11 *p=11 *q=11


clang-7.0.1-O2 Addresses: p=0x10000101c q=0x10000101c
x=1 y=11 *p=11 *q=11


clang-7.0.1-O3 Addresses: p=0x10000101c q=0x10000101c
x=1 y=11 *p=11 *q=11


clang-7.0.1-O2-no-strict-aliasing Addresses: p=0x10000101c q=0x10000101c
x=1 y=11 *p=11 *q=11


clang-7.0.1-O3-no-strict-aliasing Addresses: p=0x10000101c q=0x10000101c
x=1 y=11 *p=11 *q=11


icc-19-O0 Addresses: p=0x600b5c q=0x600b5c
x=1 y=11 *p=11 *q=11


icc-19-O2 Addresses: p=0x6046c4 q=0x6046c4
x=1 y=2 *p=11 *q=11


icc-19-O3 Addresses: p=0x6046c4 q=0x6046c4
x=1 y=2 *p=11 *q=11


icc-19-O2-no-strict-aliasing Addresses: p=0x6046c4 q=0x6046c4
x=1 y=2 *p=11 *q=11


icc-19-O3-no-strict-aliasing Addresses: p=0x6046c4 q=0x6046c4
x=1 y=2 *p=11 *q=11