[Bug rtl-optimization/66790] Invalid uninitialized register handling in REE

[bonzini at gnu dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66790

--- Comment #35 from Paolo Bonzini <bonzini at gnu dot org> ---
Comment on attachment 36377
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36377
Updated candidate patch

> +     This problem determines which registers may be uninitialized. It first
> +     assumes these are all initialized and then it eliminates the ones reached
> +     by paths without crossing a definition.  The IN bitmap is clear at first
> +     (i.e. all registers are assumed not to be initialized) so don't consider
> +     its value the first time.  */
> +  return bitmap_and_into (op1, op2);

Is this comment obsolete?  The IN bitmap is all set at first.  Otherwise looks
good.