On Thu, Apr 25, 2013 at 3:23 PM, Marek Polacek <pola...@redhat.com> wrote:
> This is an attempt to fix PR57066, where when folding logb call,
> we returned -Inf for logb(-Inf), which is not correct.
>
> I had to adjust one testcase, because it checked for a wrong value.
>
> What I don't know yet is what we should return for -Nan, it should be
> in C9X standard, but I don't have it by hand.
>
> Does this look sane? So far regtested/bootstrapped on x86_64-linux.
>
> 2013-04-25 Marek Polacek <pola...@redhat.com>
>
> * builtins.c (fold_builtin_logb): Return +Inf for -Inf.
>
> * gcc.dg/torture/builtin-logb-1.c: Adjust testcase.
>
> --- gcc/builtins.c.mp 2013-04-25 12:52:37.463451032 +0200
> +++ gcc/builtins.c 2013-04-25 14:26:33.963099851 +0200
> @@ -9698,7 +9698,12 @@ fold_builtin_logb (location_t loc, tree
> case rvc_inf:
> /* If arg is Inf or NaN and we're logb, return it. */
> if (TREE_CODE (rettype) == REAL_TYPE)
> - return fold_convert_loc (loc, rettype, arg);
> + {
> + /* For logb(-Inf) we have to return +Inf. */
> + if (value->cl == rvc_inf && !tree_expr_nonnegative_p (arg))
> + real_inf (TREE_REAL_CST_PTR (arg));
Please don't modify arg in-place but simply use
REAL_VALUE_TYPE tem;
real_inf (&tem);
return build_real (rettype, tem);
> + return fold_convert_loc (loc, rettype, arg);
> + }
> /* Fall through... */
> case rvc_zero:
> /* Zero may set errno and/or raise an exception for logb, also
> --- gcc/testsuite/gcc.dg/torture/builtin-logb-1.c.mp 2013-04-25
> 13:23:18.408224450 +0200
> +++ gcc/testsuite/gcc.dg/torture/builtin-logb-1.c 2013-04-25
> 14:28:48.900534671 +0200
> @@ -48,19 +48,19 @@ extern void link_error(int);
> /* Test if FUNCRES(FUNC(NEG FUNCARG(ARGARG))) is false. Check the
> sign as well. */
> #ifndef __SPU__
> -#define TESTIT3(FUNC,NEG,FUNCARG,ARGARG,FUNCRES) do { \
> +#define TESTIT3(FUNC,NEG,FUNCARG,ARGARG,FUNCRES,NEG2) do { \
> if (!__builtin_##FUNCRES##f(__builtin_##FUNC(NEG
> __builtin_##FUNCARG##f(ARGARG))) \
> - || CKSGN_F(__builtin_##FUNC##f(NEG __builtin_##FUNCARG##f(ARGARG)),
> NEG __builtin_##FUNCARG##f(ARGARG))) \
> + || CKSGN_F(__builtin_##FUNC##f(NEG __builtin_##FUNCARG##f(ARGARG)),
> NEG2 __builtin_##FUNCARG##f(ARGARG))) \
> link_error(__LINE__); \
> if (!__builtin_##FUNCRES(__builtin_##FUNC(NEG
> __builtin_##FUNCARG(ARGARG))) \
> - || CKSGN(__builtin_##FUNC(NEG __builtin_##FUNCARG(ARGARG)), NEG
> __builtin_##FUNCARG(ARGARG))) \
> + || CKSGN(__builtin_##FUNC(NEG __builtin_##FUNCARG(ARGARG)), NEG2
> __builtin_##FUNCARG(ARGARG))) \
> link_error(__LINE__); \
> if (!__builtin_##FUNCRES##l(__builtin_##FUNC##l(NEG
> __builtin_##FUNCARG##l(ARGARG))) \
> - || CKSGN_L(__builtin_##FUNC##l(NEG __builtin_##FUNCARG##l(ARGARG)),
> NEG __builtin_##FUNCARG##l(ARGARG))) \
> + || CKSGN_L(__builtin_##FUNC##l(NEG __builtin_##FUNCARG##l(ARGARG)),
> NEG2 __builtin_##FUNCARG##l(ARGARG))) \
> link_error(__LINE__); \
> } while (0)
> #else
> -#define TESTIT3(FUNC,NEG,FUNCARG,ARGARG,FUNCRES) do { \
> +#define TESTIT3(FUNC,NEG,FUNCARG,ARGARG,FUNCRES,NEG2) do { \
> /* SPU single-precision floating point format does not support Inf or Nan.
> */ \
> if (!__builtin_##FUNCRES(__builtin_##FUNC(NEG
> __builtin_##FUNCARG(ARGARG))) \
> || CKSGN(__builtin_##FUNC(NEG __builtin_##FUNCARG(ARGARG)), NEG
> __builtin_##FUNCARG(ARGARG))) \
> @@ -173,15 +173,15 @@ foo(void)
>
> /* Test for f(+-Inf) -> +-Inf and f(+-NaN) -> +-NaN, regardless of
> the radix. */
> - TESTIT3 (logb, ,inf, , isinf);
> - TESTIT3 (logb, - ,inf, , isinf);
> - TESTIT3 (logb, ,nan, "", isnan);
> - TESTIT3 (logb, - ,nan, "", isnan);
> -
> - TESTIT3 (significand, ,inf, , isinf);
> - TESTIT3 (significand, - ,inf, , isinf);
> - TESTIT3 (significand, ,nan, "", isnan);
> - TESTIT3 (significand, - ,nan, "", isnan);
> + TESTIT3 (logb, ,inf, , isinf, );
> + TESTIT3 (logb, - ,inf, , isinf, );
> + TESTIT3 (logb, ,nan, "", isnan, );
> + TESTIT3 (logb, - ,nan, "", isnan, -);
> +
> + TESTIT3 (significand, ,inf, , isinf, );
> + TESTIT3 (significand, - ,inf, , isinf, -);
> + TESTIT3 (significand, ,nan, "", isnan, );
> + TESTIT3 (significand, - ,nan, "", isnan, -);
> }
>
> int main()
>
> Marek
