[PATCH] Have fold transform bool_var != 1 to !bool_var

[Andrew Pinski]

I noticed that fold was not converting bool_var != 1 (and bool_var == 0) to
!bool_var which gives a little better code generation for the function like:
_Bool f(_Bool a)
{
  return a!=1;
}


For x86_64 currently we get:
        xorl    %eax, %eax
        cmpb    $1, %dil
        setne   %al
        ret

With the patch I am posting, we get it to:
        movzbl  %dil, %eax
        xorl    $1, %eax
        ret

Which is much better and shorter.


OK? Bootstapped and tested on x86_64-linux-gnu with no
regressions.

Thanks,
Andrew Pinski

ChangeLog:
	* fold-const.c (fold_build): Convert bool_var != 1 and
	bool_var == 0 to !bool_var.

	* gcc.dg/tree-ssa/bool-10.c: New test.
	* gcc.dg/tree-ssa/bool-11.c: New test.
	* /gcc.dg/tree-ssa/bool-7.c: Un-xfail.
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