Example: provenance_equality_global_fn_yx.c

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    #include <stdio.h>
    #include <string.h> 
    int y=2, x=1;
    void f(int* p, int* q) {
      _Bool b = (p==q);
      // can this be false even with identical addresses?
      printf("(p==q) = %s\n", b?"true":"false");
      return;
    }
    int main() {
      int *p = &x + 1;
      int *q = &y;
      printf("Addresses: p=%p q=%p\n",(void*)p,(void*)q);
      f(p,q);
      return 0;
    }
[link to run test in Cerberus]

Experimental data (what does this mean?) 



cerberus-concrete-PVI EXECUTION 0 (exit = Specified(0)):
Addresses: p=(@8, 0x50) q=(@7, 0x48)
(p==q) = false

EXECUTION 1 (exit = Specified(0)):
Addresses: p=(@8, 0x50) q=(@7, 0x48)
(p==q) = false


cerberus-concrete-PNVI EXECUTION 0 (exit = Specified(0)):
Addresses: p=(@8, 0x50) q=(@7, 0x48)
(p==q) = false

EXECUTION 1 (exit = Specified(0)):
Addresses: p=(@8, 0x50) q=(@7, 0x48)
(p==q) = false


gcc-8.1-O0 Addresses: p=0x600a10 q=0x600a08
(p==q) = false


gcc-8.1-O2 Addresses: p=0x6009cc q=0x6009cc
(p==q) = false


gcc-8.1-O3 Addresses: p=0x6009cc q=0x6009cc
(p==q) = false


gcc-8.1-O2-no-strict-aliasing Addresses: p=0x6009cc q=0x6009cc
(p==q) = false


gcc-8.1-O3-no-strict-aliasing Addresses: p=0x6009cc q=0x6009cc
(p==q) = false


clang-6.0-O0 Addresses: p=0x601040 q=0x601038
(p==q) = false


clang-6.0-O2 Addresses: p=0x601040 q=0x601038
(p==q) = false


clang-6.0-O3 Addresses: p=0x601040 q=0x601038
(p==q) = false


clang-6.0-O2-no-strict-aliasing Addresses: p=0x601040 q=0x601038
(p==q) = false


clang-6.0-O3-no-strict-aliasing Addresses: p=0x601040 q=0x601038
(p==q) = false


clang-6.0-UBSAN Addresses: p=0x631b58 q=0x631b50
(p==q) = false


clang-6.0-ASAN Addresses: p=0x716ba4 q=0x716b60
(p==q) = false


clang-6.0-MSAN Addresses: p=0x6b7af8 q=0x6b7af0
(p==q) = false


icc-19-O0 Addresses: p=0x600b38 q=0x600b30
(p==q) = false


icc-19-O2 Addresses: p=0x6046c8 q=0x6046c0
(p==q) = false


icc-19-O3 Addresses: p=0x6046c8 q=0x6046c0
(p==q) = false


icc-19-O2-no-strict-aliasing Addresses: p=0x6046c8 q=0x6046c0
(p==q) = false


icc-19-O3-no-strict-aliasing Addresses: p=0x6046c8 q=0x6046c0
(p==q) = false


compcert-3.4 Addresses: p=0x601040 q=0x601038
(p==q) = false


compcert-3.4-O Addresses: p=0x601040 q=0x601038
(p==q) = false


kcc-1.0 Addresses: p=(nil) q=(nil)
(p==q) = true
Comparison of unspecified value:
      > in f at provenance_equality_global_fn_yx.c:7:3
        in main at provenance_equality_global_fn_yx.c:14:3

    Unspecified value or behavior (USP-CERL7):
        see C11 section 6.5.9 http://rvdoc.org/C11/6.5.9
        see MISRA-C section 8.1:3 http://rvdoc.org/MISRA-C/8.1