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* [PATCH] Builtin function roundeven folding implementation
@ 2019-06-28  3:40 Tejas Joshi
  2019-07-29 16:49 ` Martin Jambor
  2019-08-09 21:26 ` Joseph Myers
  0 siblings, 2 replies; 16+ messages in thread
From: Tejas Joshi @ 2019-06-28  3:40 UTC (permalink / raw)
  To: gcc-patches; +Cc: Martin Jambor, hubicka, joseph

[-- Attachment #1: Type: text/plain, Size: 1408 bytes --]

Hi.
This patch includes implementation of new function roundeven along
with two utility functions. The patch bootstraps on x86_64-linux-gnu
and passes regression tests.

Thanks,
Tejas

gcc/ChangeLog:

2019-06-12  Tejas Joshi  <tejasjoshi9673@gmail.com>

    * builtins.c (mathfn_built_in_2): Added CASE_MATHFN for ROUNDEVEN.
    * builtins.def: Added function definitions for roundeven function
    variants.
    * fold-const-call.c (fold_const_call_ss): Added case for function
    call and fold_const_conversion call for roundeven function.
    * fold-const.c (negate_mathfn_p): Added case for roundeven function.
    (tree_call_nonnegative_warnv_p): Added case for roundeven function.
    (integer_valued_real_call_p): Added case for roundeven function.
    * real.c (is_even): New function. Returns true if real number is
    even, otherwise returns false.
    (is_halfway_below): New function. Returns true if real number is
    halfway between two integers, else return false.
    (real_roundeven): New function. Round real number to nearest
    integer, rounding halfway cases towards even.
    * real.h (real_value): Added descriptive comments.
    Added function declaration for roundeven function.

gcc/testsuite/ChangeLog:

2019-06-12  Tejas Joshi  <tejasjoshi9673@gmail.com>

    * gcc.dg/torture/builtin-round-roundeven.c: New test.
    * gcc.dg/torture/builtin-round-roundevenf128.c: New test.

[-- Attachment #2: roundeven.diff --]
[-- Type: text/x-patch, Size: 9089 bytes --]

diff --git a/gcc/builtins.c b/gcc/builtins.c
index 3463ffb1539..85a945877a4 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -2085,6 +2085,7 @@ 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 6d41bdb4f44..8bb7027aac7 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 702c8b4057a..d9b546e6803 100644
--- a/gcc/fold-const-call.c
+++ b/gcc/fold-const-call.c
@@ -836,6 +836,15 @@ 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);
 
@@ -898,6 +907,10 @@ 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 0ca472d422f..07d82a17e25 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:
@@ -13063,6 +13065,8 @@ 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:
@@ -13586,6 +13590,8 @@ 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 0164f097a53..ab71430709f 100644
--- a/gcc/real.c
+++ b/gcc/real.c
@@ -5010,6 +5010,89 @@ real_round (REAL_VALUE_TYPE *r, format_helper fmt,
     real_convert (r, fmt, r);
 }
 
+/* Return true including 0 if integer part of R is even, else return
+   false. The function is not valid for rvc_inf and rvc_nan classes. */
+
+bool
+is_even (REAL_VALUE_TYPE *r)
+{
+  gcc_assert (r->cl != rvc_inf);
+  gcc_assert (r->cl != rvc_nan);
+
+  if (r->cl == rvc_zero)
+    return true;
+
+  /* For (-1,1), number is even. */
+  if (REAL_EXP (r) <= 0)
+    return true;
+
+  /* Check lowest bit, if not set, return true. */
+  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;
+  }
+
+  else
+    return true;
+
+  return false;
+}
+
+/* Return true if R is halfway between two integers, else return
+   false. The function is not valid for rvc_inf and rvc_nan classes. */
+
+bool
+is_halfway_below (const REAL_VALUE_TYPE *r)
+{
+  gcc_assert (r->cl != rvc_inf);
+  gcc_assert (r->cl != rvc_nan);
+  int i;
+
+  /* For numbers (-0.5,0) and (0,0.5). */
+  if (REAL_EXP (r) < 0)
+    return false;
+
+  else if (REAL_EXP (r) < SIGNIFICAND_BITS)
+  {
+    unsigned int n = SIGNIFICAND_BITS - REAL_EXP (r) - 1;
+    int 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 % 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);
+    if (fmt)
+      real_convert (r, fmt, r);
+  }
+  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 95b9db83d24..76889bff0ea 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];
 };
 
@@ -500,6 +507,8 @@ 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 *);
diff --git a/gcc/testsuite/gcc.dg/torture/builtin-round-roundeven.c b/gcc/testsuite/gcc.dg/torture/builtin-round-roundeven.c
new file mode 100644
index 00000000000..f75adf6ec8a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/builtin-round-roundeven.c
@@ -0,0 +1,23 @@
+/* { 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;
+}
\ No newline at end of file
diff --git a/gcc/testsuite/gcc.dg/torture/builtin-round-roundevenf128.c b/gcc/testsuite/gcc.dg/torture/builtin-round-roundevenf128.c
new file mode 100644
index 00000000000..592bad49623
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/builtin-round-roundevenf128.c
@@ -0,0 +1,20 @@
+/* { 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##f128 (VALUE) != RESULT) link_error (__LINE__);
+
+int
+main (void)
+{
+  TEST(roundeven,  (0x1p64+0.5f128), (0x1p64f128));
+  TEST(roundeven,  (0x1p63+0.5f128), (0x1p63f128));
+  TEST(roundeven,  (0x1p63-0.5f128), (0x1p63f128));
+  TEST(roundeven,  (0x1p64-0.5f128), (0x1p64f128));
+  TEST(roundeven,  (0x1p64+0.501f128), (0x1p64+1.0f128));
+  TEST(roundeven,  (0x1.C00000000000039A5653p1f128), (0x1p2f128))
+  return 0;
+}
\ No newline at end of file

^ permalink raw reply	[flat|nested] 16+ messages in thread
end of thread, other threads:[~2020-02-12 20:56 UTC | newest]

Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-06-28  3:40 [PATCH] Builtin function roundeven folding implementation Tejas Joshi
2019-07-29 16:49 ` Martin Jambor
2019-08-09 21:26 ` Joseph Myers
2019-08-14  7:24   ` Tejas Joshi
2019-08-21 11:52     ` Martin Jambor
2019-08-21 12:48       ` Joseph Myers
2019-08-21 19:10         ` Martin Jambor
2019-08-21 20:50           ` Joseph Myers
2019-08-22 14:40             ` Martin Jambor
2019-08-22 15:52               ` Joseph Myers
2019-08-22 21:39                 ` Tejas Joshi
2019-08-23 12:21                   ` Martin Jambor
2019-08-23 21:24                   ` Joseph Myers
2019-08-25 20:28                     ` Tejas Joshi
2020-02-12  6:20                     ` [PATCH] real: Fix roundeven on inf/nan [PR93663] Jakub Jelinek
2020-02-12 20:56                       ` Joseph Myers

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