CSA evaluates `((b)+1)==((0)+1)` to be FALSE with the fact that `b == 0`

[Geoffrey1014]

date: 2023-1-10 commit: args: --analyze -Xclang -analyzer-stats -Xclang -analyzer-checker=core,debug.ExprInspection test:

#include "stdio.h"
#include <stdint.h>
#include <stdbool.h>

void clang_analyzer_eval();

int32_t a() {
  uint8_t *b = 0;
  if (b == 0) {
    clang_analyzer_eval((b == 0)==true);
    clang_analyzer_eval(((b)!=(0))==false);
    clang_analyzer_eval(((b)+0)==((0)+0));
    clang_analyzer_eval(((b)+0)<((0)+1));
    clang_analyzer_eval(((b)+1)==((0)+1));
    clang_analyzer_eval(((b)+0)<((0)+2));
    clang_analyzer_eval(((b)+1)<((0)+2));
    clang_analyzer_eval(((b)+2)==((0)+2));
    clang_analyzer_eval(((b)-0)==((0)-0));
    clang_analyzer_eval(true);
    ;
  }
}

report: fix: original:

[Geoffrey1014]

https://godbolt.org/z/1v4sard7n

Output:

<source>:10:5: warning: TRUE [debug.ExprInspection]
    clang_analyzer_eval((b == 0)==true);
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:11:5: warning: TRUE [debug.ExprInspection]
    clang_analyzer_eval(((b)!=(0))==false);
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:12:5: warning: TRUE [debug.ExprInspection]
    clang_analyzer_eval(((b)+0)==((0)+0));
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:13:5: warning: TRUE [debug.ExprInspection]
    clang_analyzer_eval(((b)+0)<((0)+1));
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:14:5: warning: FALSE [debug.ExprInspection]
    clang_analyzer_eval(((b)+1)==((0)+1));
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:15:5: warning: TRUE [debug.ExprInspection]
    clang_analyzer_eval(((b)+0)<((0)+2));
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:16:5: warning: TRUE [debug.ExprInspection]
    clang_analyzer_eval(((b)+1)<((0)+2));
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:17:5: warning: FALSE [debug.ExprInspection]
    clang_analyzer_eval(((b)+2)==((0)+2));
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:18:5: warning: TRUE [debug.ExprInspection]
    clang_analyzer_eval(((b)-0)==((0)-0));
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:19:5: warning: TRUE [debug.ExprInspection]
    clang_analyzer_eval(true);
    ^~~~~~~~~~~~~~~~~~~~~~~~~
===-------------------------------------------------------------------------===
                                Analyzer timers
===-------------------------------------------------------------------------===
  Total Execution Time: 0.0030 seconds (0.0273 wall clock)

   ---User Time---   --System Time--   --User+System--   ---Wall Time---  --- Name ---
   0.0000 (  0.0%)   0.0014 ( 48.0%)   0.0014 ( 46.6%)   0.0145 ( 53.1%)  Path exploration time
   0.0001 (100.0%)   0.0004 ( 15.2%)   0.0005 ( 17.7%)   0.0107 ( 39.1%)  Syntax-based analysis time
   0.0000 (  0.0%)   0.0011 ( 36.7%)   0.0011 ( 35.6%)   0.0021 (  7.7%)  Path-sensitive report post-processing time
   0.0001 (100.0%)   0.0029 (100.0%)   0.0030 (100.0%)   0.0273 (100.0%)  Total

10 warnings generated.
Compiler returned: 0

[Geoffrey1014]

duplicate of https://github.com/Geoffrey1014/SA_Bugs/issues/30