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Date: Tue, 20 Apr 2004 14:44:00 -0000
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From: "dann at godzilla dot ics dot uci dot edu" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug optimization/15017] [tree-ssa] compare (equal) with casts are not removed
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X-SW-Source: 2004-04/txt/msg01700.txt.bz2
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------- Additional Comments From dann at godzilla dot ics dot uci dot edu  2004-04-20 14:15 -------
It seems that the underlying problem is casting bools to int before
using them.

For example look at the .original dump:

;; Function foo0 (foo0)
;; enabled by -tree-original

{
   if ((int)a != 0)
      return <return-value> = 1;
   else
       return <return-value> = 0;

}

The cast does not seem to be needed, != can take a bool as an argument. 
Not emitting casts there will simplify the work the optimizers have to do. 

I only gave you one function, here is the file I was playing with:

_Bool foo (_Bool a, _Bool b)
{
  if (a != b)
    return 1;
  else
    return 0;
}

_Bool foo0 (_Bool a)
{
  if (a)
    return 1;
  else
    return 0;
}

_Bool bar (_Bool a)
{
  return a;
}

_Bool foo1 (_Bool a, _Bool b)
{
  if (bar(a))
    return 1;
  else
    return 0;
}

struct mm
{
  _Bool a;
  _Bool b;
} T;

_Bool foo2 (void)
{
  if (T.a != T.b)
    return 1;
  else
    return 0;
}

static _Bool as, bs;
_Bool foo3 (void) {
  if (as != bs) return 1;
  else  return 0;
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15017