Hello.
The f128 suffix worked. Based on all the corrections you all pointed
out, I have created another patch. I think I took most of the things
under consideration but please mention if I missed anything. The
following test cases were inspected with this patch. I am not sure if
the second test case is supposed to be carried out like I did.
Thanks,
-Tejas
/* { dg-do link } */
extern int link_error (int);
#define TEST(FN, VALUE, RESULT) \
if (__builtin_##FN (VALUE) != RESULT) link_error (__LINE__);
int
main (void)
{
TEST(roundeven, 0, 0);
TEST(roundeven, 0.5, 0);
TEST(roundeven, -0.5, 0);
TEST(roundeven, 6, 6);
TEST(roundeven, -8, -8);
TEST(roundeven, 2.5, 2);
TEST(roundeven, 3.5, 4);
TEST(roundeven, -1.5, -2);
TEST(roundeven, 3.499, 3);
TEST(roundeven, 3.501, 4);
return 0;
}
second test case :
/* { dg-do link } */
/* { dg-add-options float128 } */
/* { dg-require-effective-target float128 } */
extern int link_error (int);
#define TEST(FN, VALUE, RESULT) \
if (__builtin_##FN (VALUE) != RESULT) link_error (__LINE__);
int
main (void)
{
TEST(roundevenf128, (0x1p64+0.5), (0x1p64));
return 0;
}
On Fri, 31 May 2019 at 15:41, Martin Jambor <[email protected]> wrote:
>
> On Thu, May 30 2019, Segher Boessenkool wrote:
> > On Thu, May 30, 2019 at 07:08:45PM +0200, Martin Jambor wrote:
> >> Interesting, I was also puzzled for a moment. But notice that:
> >>
> >> int main ()
> >> {
> >> _Float128 x = 18446744073709551617.5f128;
> >> _Float128 y = __builtin_roundf128 (x);
> >> }
> >>
> >> behaves as expected... the difference is of course the suffix pegged to
> >> the literal constant (see
> >> https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Floating-Types.html).
> >>
> >> I would also expect GCC to use a larger type if a constant does not fit
> >> into a double, but apparently that does not happen. I would have to
> >> check but it is probably the right behavior according to the standard.
> >
> > 6.4.4.2/4: "An unsuffixed floating constant has type double." I don't
> > think your suggestion would be okay?
>
> Sorry if I was not clear but I was definitely not suggesting that we
> change this (or anything). I wrote that I was also surprised but
> believed that GCC was doing the correct thing.
>
> Thanks for pointing out where exactly the standard says what has to be
> done though.
>
> Martin
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 25e01e4092b..0b2d6bf82f9 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -2067,6 +2067,7 @@ mathfn_built_in_2 (tree type, combined_fn fn)
CASE_MATHFN (REMQUO)
CASE_MATHFN_FLOATN (RINT)
CASE_MATHFN_FLOATN (ROUND)
+ CASE_MATHFN (ROUNDEVEN)
CASE_MATHFN (SCALB)
CASE_MATHFN (SCALBLN)
CASE_MATHFN (SCALBN)
diff --git a/gcc/builtins.def b/gcc/builtins.def
index ef89729fd0c..f284a3eae3b 100644
--- a/gcc/builtins.def
+++ b/gcc/builtins.def
@@ -542,12 +542,18 @@ DEF_C99_BUILTIN (BUILT_IN_RINTL, "rintl", BT_FN_LONGDOUBLE_LONGDOUBLE, AT
#define RINT_TYPE(F) BT_FN_##F##_##F
DEF_EXT_LIB_FLOATN_NX_BUILTINS (BUILT_IN_RINT, "rint", RINT_TYPE, ATTR_CONST_NOTHROW_LEAF_LIST)
#undef RINT_TYPE
+DEF_EXT_LIB_BUILTIN (BUILT_IN_ROUNDEVEN, "roundeven", BT_FN_DOUBLE_DOUBLE, ATTR_CONST_NOTHROW_LEAF_LIST)
+DEF_EXT_LIB_BUILTIN (BUILT_IN_ROUNDEVENF, "roundevenf", BT_FN_FLOAT_FLOAT, ATTR_CONST_NOTHROW_LEAF_LIST)
+DEF_EXT_LIB_BUILTIN (BUILT_IN_ROUNDEVENL, "roundevenl", BT_FN_LONGDOUBLE_LONGDOUBLE, ATTR_CONST_NOTHROW_LEAF_LIST)
DEF_C99_BUILTIN (BUILT_IN_ROUND, "round", BT_FN_DOUBLE_DOUBLE, ATTR_CONST_NOTHROW_LEAF_LIST)
DEF_C99_BUILTIN (BUILT_IN_ROUNDF, "roundf", BT_FN_FLOAT_FLOAT, ATTR_CONST_NOTHROW_LEAF_LIST)
DEF_C99_BUILTIN (BUILT_IN_ROUNDL, "roundl", BT_FN_LONGDOUBLE_LONGDOUBLE, ATTR_CONST_NOTHROW_LEAF_LIST)
#define ROUND_TYPE(F) BT_FN_##F##_##F
DEF_EXT_LIB_FLOATN_NX_BUILTINS (BUILT_IN_ROUND, "round", ROUND_TYPE, ATTR_CONST_NOTHROW_LEAF_LIST)
#undef ROUND_TYPE
+#define ROUNDEVEN_TYPE(F) BT_FN_##F##_##F
+DEF_EXT_LIB_FLOATN_NX_BUILTINS (BUILT_IN_ROUNDEVEN, "roundeven", ROUNDEVEN_TYPE, ATTR_CONST_NOTHROW_LEAF_LIST)
+#undef ROUNDEVEN_TYPE
DEF_EXT_LIB_BUILTIN (BUILT_IN_SCALB, "scalb", BT_FN_DOUBLE_DOUBLE_DOUBLE, ATTR_MATHFN_FPROUNDING_ERRNO)
DEF_EXT_LIB_BUILTIN (BUILT_IN_SCALBF, "scalbf", BT_FN_FLOAT_FLOAT_FLOAT, ATTR_MATHFN_FPROUNDING_ERRNO)
DEF_EXT_LIB_BUILTIN (BUILT_IN_SCALBL, "scalbl", BT_FN_LONGDOUBLE_LONGDOUBLE_LONGDOUBLE, ATTR_MATHFN_FPROUNDING_ERRNO)
diff --git a/gcc/fold-const-call.c b/gcc/fold-const-call.c
index 06a420601c0..54315d057a2 100644
--- a/gcc/fold-const-call.c
+++ b/gcc/fold-const-call.c
@@ -792,6 +792,15 @@ fold_const_call_ss (real_value *result, combined_fn fn,
}
return false;
+ CASE_CFN_ROUNDEVEN:
+ CASE_CFN_ROUNDEVEN_FN:
+ if (!REAL_VALUE_ISNAN (*arg) || !flag_errno_math)
+ {
+ real_roundeven (result, format, arg);
+ return true;
+ }
+ return false;
+
CASE_CFN_LOGB:
return fold_const_logb (result, arg, format);
@@ -854,6 +863,10 @@ fold_const_call_ss (wide_int *result, combined_fn fn,
return fold_const_conversion (result, real_round, arg,
precision, format);
+ CASE_CFN_ROUNDEVEN:
+ CASE_CFN_ROUNDEVEN_FN:
+ return fold_const_conversion (result, real_roundeven, arg, precision, format);
+
CASE_CFN_IRINT:
CASE_CFN_LRINT:
CASE_CFN_LLRINT:
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 59cedeafd71..ab96f197d5f 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -329,6 +329,8 @@ negate_mathfn_p (combined_fn fn)
CASE_CFN_LLROUND:
CASE_CFN_LROUND:
CASE_CFN_ROUND:
+ CASE_CFN_ROUNDEVEN:
+ CASE_CFN_ROUNDEVEN_FN:
CASE_CFN_SIN:
CASE_CFN_SINH:
CASE_CFN_TAN:
@@ -13060,6 +13062,8 @@ tree_call_nonnegative_warnv_p (tree type, combined_fn fn, tree arg0, tree arg1,
CASE_CFN_RINT_FN:
CASE_CFN_ROUND:
CASE_CFN_ROUND_FN:
+ CASE_CFN_ROUNDEVEN:
+ CASE_CFN_ROUNDEVEN_FN:
CASE_CFN_SCALB:
CASE_CFN_SCALBLN:
CASE_CFN_SCALBN:
@@ -13583,6 +13587,8 @@ integer_valued_real_call_p (combined_fn fn, tree arg0, tree arg1, int depth)
CASE_CFN_RINT_FN:
CASE_CFN_ROUND:
CASE_CFN_ROUND_FN:
+ CASE_CFN_ROUNDEVEN:
+ CASE_CFN_ROUNDEVEN_FN:
CASE_CFN_TRUNC:
CASE_CFN_TRUNC_FN:
return true;
diff --git a/gcc/real.c b/gcc/real.c
index f822ae82d61..541fa6b6e43 100644
--- a/gcc/real.c
+++ b/gcc/real.c
@@ -5010,6 +5010,80 @@ real_round (REAL_VALUE_TYPE *r, format_helper fmt,
real_convert (r, fmt, r);
}
+/* Return true if integer part of R is even, else return false. */
+
+bool
+is_even (REAL_VALUE_TYPE *r)
+{
+ if (REAL_EXP (r) <= 0)
+ return false;
+
+ else if (REAL_EXP (r) < SIGNIFICAND_BITS)
+ {
+ unsigned int n = SIGNIFICAND_BITS - REAL_EXP (r);
+ int w = n / HOST_BITS_PER_LONG;
+
+ unsigned long num = ((unsigned long)1 << (n % HOST_BITS_PER_LONG));
+
+ if ((r->sig[w] & num) == 0)
+ return true;
+ }
+ return false;
+}
+
+/* Return true if R is halfway between two integers, else return false. */
+
+bool
+is_halfway_below (const REAL_VALUE_TYPE *r)
+{
+ if (REAL_EXP (r) < 0)
+ return false;
+
+ if (REAL_EXP (r) == 0)
+ {
+ unsigned long temp = ((unsigned long)1 << 63);
+
+ if (((r->sig[SIGSZ-1] & temp) != 0) && ((r->sig[SIGSZ-1] & (temp-1)) == 0))
+ return true;
+ else
+ return false;
+ }
+
+ else if (REAL_EXP (r) < SIGNIFICAND_BITS)
+ {
+ unsigned int n = SIGNIFICAND_BITS - REAL_EXP (r);
+ int i, w = n / HOST_BITS_PER_LONG;
+
+ for (i = 0; i < w; ++i)
+ {
+ if (r->sig[i] != 0)
+ return false;
+ }
+
+ unsigned long num = ((unsigned long)1 << ((n - 1) % HOST_BITS_PER_LONG));
+
+ if (((r->sig[w] & num) != 0) && ((r->sig[w] & (num-1)) == 0))
+ return true;
+ }
+ return false;
+}
+
+/* Round X to nearest integer, rounding halfway cases towards even. */
+
+void
+real_roundeven (REAL_VALUE_TYPE *r, format_helper fmt,
+ const REAL_VALUE_TYPE *x)
+{
+ if (is_halfway_below (x))
+ {
+ do_add (r, x, &dconsthalf, x->sign);
+ if (!is_even (r))
+ do_add (r, r, &dconstm1, x->sign);
+ }
+ else
+ real_round (r, fmt, x);
+}
+
/* Set the sign of R to the sign of X. */
void
diff --git a/gcc/real.h b/gcc/real.h
index 0ce42565708..ebe66d234af 100644
--- a/gcc/real.h
+++ b/gcc/real.h
@@ -41,11 +41,18 @@ struct GTY(()) real_value {
sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
be miscomputed. */
unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
+ /* 1 if number is decimal floating point */
unsigned int decimal : 1;
+ /* 1 if number is negative */
unsigned int sign : 1;
+ /* 1 if number is signalling */
unsigned int signalling : 1;
+ /* 1 if number is canonical
+ All are generally used for handling cases in real.c */
unsigned int canonical : 1;
+ /* unbiased exponent of the number */
unsigned int uexp : EXP_BITS;
+ /* significand of the number */
unsigned long sig[SIGSZ];
};
@@ -499,6 +506,8 @@ extern void real_ceil (REAL_VALUE_TYPE *, format_helper,
const REAL_VALUE_TYPE *);
extern void real_round (REAL_VALUE_TYPE *, format_helper,
const REAL_VALUE_TYPE *);
+extern void real_roundeven (REAL_VALUE_TYPE *, format_helper,
+ const REAL_VALUE_TYPE *);
/* Set the sign of R to the sign of X. */
extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
