why valueflow does not get the value of the whole expression

[wy163]

HI,
I used the cppcheck with --debug to see the value flow. The target file is as below.

int func(int x) {
    int y = 1 + x * x;
    return y;
}

void main() {
    func(1);
    func(2);
}

I got the output from the cppcheck. I find that the possible values of x and x * x are listed, but why the token y is "always symbolic". Why the possible values of 'y' , '+', or '=' in the expression 'y = 1 + x * x' are no listed? Thanks!

##file ../cppcheck-2.16.0_new/wy_test/test/valueflow.c
1: int func ( int x@var1 ) {
2: int y@var2 ; y@var2 =@exprUNIQUE 1 +@exprUNIQUE x@var1 *@exprUNIQUE x@var1 ;
3: return y@var2 ;
4: }
5:
6: void main ( ) {
7: func (@exprUNIQUE 1 ) ;
8: func (@exprUNIQUE 2 ) ;
9: }



##Value flow
File ../cppcheck-2.16.0_new/wy_test/test/valueflow.c
Line 2
  1 always 1
  x possible {1@1,2@2}
  * possible {1@1,4@2}
  x possible {1@1,2@2}
Line 3
  y always symbolic=(1+x*x)
Line 7
  1 always 1
Line 8
  2 always 2

[Daniel Marjamäki]

Good question.

For me, latest git HEAD says:

##Value flow
File test1.c
Line 2
  1 always 1
  + possible {2,5}
  x possible {1@1,2@2}
  * possible {1@1,4@2}
  x possible {1@1,2@2}
Line 3
  y {symbolic=(1+x*x),2,5}
Line 7
  1 always 1
Line 8
  2 always 2

I get the same output as you with 2.16.0 and it's not optimal. I am not sure where/when it was fixed.