Example: pointer_arith_algebraic_properties_2_global.c

up: index
prev: provenance_tag_bits_via_uintptr_t_1.c
next: pointer_arith_algebraic_properties_3_global.c

1
2
3
4
5
6
7
8
9
10

    #include <stdio.h>
    #include <inttypes.h>
    int y[2], x[2];
    int main() {
      int *p=(int*)(((uintptr_t)&(x[0])) + 
        (((uintptr_t)&(y[1]))-((uintptr_t)&(y[0]))));
      *p = 11;  // is this free of undefined behaviour?
      printf("x[1]=%d *p=%d\n",x[1],*p);
      return 0;
    }
[link to run test in Cerberus]

Experimental data (what does this mean?) 



cerberus-concrete-PVI-plain x[1]=11 *p=11


cerberus-concrete-PVI-ae x[1]=11 *p=11


cerberus-concrete-PVI-ae-udi x[1]=11 *p=11


gcc-8.3-O0 x[1]=11 *p=11


gcc-8.3-O2 x[1]=11 *p=11


gcc-8.3-O3 x[1]=11 *p=11


gcc-8.3-O2-no-strict-aliasing x[1]=11 *p=11


gcc-8.3-O3-no-strict-aliasing x[1]=11 *p=11


clang-7.0.1-O0 x[1]=11 *p=11


clang-7.0.1-O2 x[1]=11 *p=11


clang-7.0.1-O3 x[1]=11 *p=11


clang-7.0.1-O2-no-strict-aliasing x[1]=11 *p=11


clang-7.0.1-O3-no-strict-aliasing x[1]=11 *p=11


icc-19-O0 x[1]=11 *p=11


icc-19-O2 x[1]=11 *p=11


icc-19-O3 x[1]=11 *p=11


icc-19-O2-no-strict-aliasing x[1]=11 *p=11


icc-19-O3-no-strict-aliasing x[1]=11 *p=11