[Bug tree-optimization/30966] New: (long long)(int_var) == (long long)(int_var1) is not simplified down to int_var == int_var1 when "expanded"

[pinskia at gcc dot gnu dot org]

Both of these functions should produce the same asm:
int f(int a, int b)
{
  long long c = a;
  long long d = b;
  return c == d;
}

int f1(int a, int b)
{
  return ((long long) a) == ((long long)b);
}

But don't at least on powerpc-darwin:
_f:
        srawi r0,r3,31
        srawi r2,r4,31
        cmpw cr7,r0,r2
        mr r9,r3
        li r3,0
        bnelr+ cr7
        cmpw cr7,r9,r4
        bnelr+ cr7
        li r3,1
        blr
_f1:
        xor r3,r3,r4
        cntlzw r3,r3
        srwi r3,r3,5
        blr


Even powerpc64-darwin does not produce the same asm, in this case f1 is worse
than f:
_f:
        xor r3,r3,r4
        cntlzd r3,r3
        srdi r3,r3,6
        blr

_f1:
        xor r4,r3,r4
        cntlzw r4,r4
        srwi r4,r4,5
        extsw r3,r4
        blr

But only because there is an extra sign extends (I will file this in a
different bug).


-- 
           Summary: (long long)(int_var) == (long long)(int_var1) is not
                    simplified down to int_var == int_var1 when "expanded"
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30966