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 <mjam...@suse.cz> 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 *);