missed optimization: Optimization based on the first of the two conditions

[k-arrows]

Test case from gcc testsuite:
https://github.com/gcc-mirror/gcc/blob/master/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-11.c

int f(int a, int b, int c)
{
  if (a == 0 && b > c)
   return 0;
 return a;
}

int g(int a, int b, int c)
{
  if (a == 42 && b > c)
   return 42;
 return a;
}

int h(int a, int b, int c, int d)
{
  if (a == d && b > c)
   return d;
 return a;
}

https://godbolt.org/z/hd8Pb116n

Any of these functions can be optimized to a function which returns a. I feel like there may be a duplicate of this issue.

[nikic]

Can probably be solved by supporting and/or of conditions for the simplifySelectWithICmpEq() fold.

[sun-jacobi]

Hi @nikic @k-arrows Can I work on this issue ?

[sun-jacobi]

Alive2 proof: https://alive2.llvm.org/ce/z/JeADtD

[k-arrows]

Can I work on this issue ?

Of course you can. There’s no need to rush.