From d02ce8eaf16d2fc6db6472268fd962e09c2fd81e Mon Sep 17 00:00:00 2001 From: Aldy Hernandez Date: Mon, 7 Nov 2022 14:18:57 +0100 Subject: [PATCH] Provide normalized and denormal format version of real_isdenormal. Implement a variant of real_isdenormal() to be used within real.cc where the argument is known to be in denormal format. Rewrite real_isdenormal() for use outside of real.cc where the argument is known to be normalized. gcc/ChangeLog: * real.cc (real_isdenormal): New. (encode_ieee_single): Call real_isdenormal. (encode_ieee_double): Same. (encode_ieee_extended): Same. (encode_ieee_quad): Same. (encode_ieee_half): Same. (encode_arm_bfloat_half): Same. * real.h (real_isdenormal): Add mode argument. Rewrite for normalized values. * value-range.cc (frange::flush_denormals_to_zero): Pass mode to real_isdenormal. --- gcc/real.cc | 28 ++++++++++++++++------------ gcc/real.h | 7 ++++--- gcc/value-range.cc | 5 +++-- 3 files changed, 23 insertions(+), 17 deletions(-) diff --git a/gcc/real.cc b/gcc/real.cc index aae7c335d59..1c71858dd01 100644 --- a/gcc/real.cc +++ b/gcc/real.cc @@ -111,6 +111,16 @@ static const REAL_VALUE_TYPE * real_digit (int); static void times_pten (REAL_VALUE_TYPE *, int); static void round_for_format (const struct real_format *, REAL_VALUE_TYPE *); + +/* Determine whether a floating-point value X is a denormal. R is + expected to be in denormal form, so this function is only + meaningful after a call to round_for_format. */ + +static inline bool +real_isdenormal (const REAL_VALUE_TYPE *r) +{ + return r->cl == rvc_normal && (r->sig[SIGSZ-1] & SIG_MSB) == 0; +} /* Initialize R with a positive zero. */ @@ -2962,7 +2972,6 @@ encode_ieee_single (const struct real_format *fmt, long *buf, { unsigned long image, sig, exp; unsigned long sign = r->sign; - bool denormal = real_isdenormal (r); image = sign << 31; sig = (r->sig[SIGSZ-1] >> (HOST_BITS_PER_LONG - 24)) & 0x7fffff; @@ -3002,7 +3011,7 @@ encode_ieee_single (const struct real_format *fmt, long *buf, /* Recall that IEEE numbers are interpreted as 1.F x 2**exp, whereas the intermediate representation is 0.F x 2**exp. Which means we're off by one. */ - if (denormal) + if (real_isdenormal (r)) exp = 0; else exp = REAL_EXP (r) + 127 - 1; @@ -3183,7 +3192,6 @@ encode_ieee_double (const struct real_format *fmt, long *buf, { unsigned long image_lo, image_hi, sig_lo, sig_hi, exp; unsigned long sign = r->sign; - bool denormal = real_isdenormal (r); image_hi = sign << 31; image_lo = 0; @@ -3255,7 +3263,7 @@ encode_ieee_double (const struct real_format *fmt, long *buf, /* Recall that IEEE numbers are interpreted as 1.F x 2**exp, whereas the intermediate representation is 0.F x 2**exp. Which means we're off by one. */ - if (denormal) + if (real_isdenormal (r)) exp = 0; else exp = REAL_EXP (r) + 1023 - 1; @@ -3441,7 +3449,6 @@ encode_ieee_extended (const struct real_format *fmt, long *buf, const REAL_VALUE_TYPE *r) { unsigned long image_hi, sig_hi, sig_lo; - bool denormal = real_isdenormal (r); image_hi = r->sign << 15; sig_hi = sig_lo = 0; @@ -3523,7 +3530,7 @@ encode_ieee_extended (const struct real_format *fmt, long *buf, this discrepancy has been taken care of by the difference in fmt->emin in round_for_format. */ - if (denormal) + if (real_isdenormal (r)) exp = 0; else { @@ -3972,7 +3979,6 @@ encode_ieee_quad (const struct real_format *fmt, long *buf, { unsigned long image3, image2, image1, image0, exp; unsigned long sign = r->sign; - bool denormal = real_isdenormal (r); REAL_VALUE_TYPE u; image3 = sign << 31; @@ -4048,7 +4054,7 @@ encode_ieee_quad (const struct real_format *fmt, long *buf, /* Recall that IEEE numbers are interpreted as 1.F x 2**exp, whereas the intermediate representation is 0.F x 2**exp. Which means we're off by one. */ - if (denormal) + if (real_isdenormal (r)) exp = 0; else exp = REAL_EXP (r) + 16383 - 1; @@ -4729,7 +4735,6 @@ encode_ieee_half (const struct real_format *fmt, long *buf, { unsigned long image, sig, exp; unsigned long sign = r->sign; - bool denormal = real_isdenormal (r); image = sign << 15; sig = (r->sig[SIGSZ-1] >> (HOST_BITS_PER_LONG - 11)) & 0x3ff; @@ -4769,7 +4774,7 @@ encode_ieee_half (const struct real_format *fmt, long *buf, /* Recall that IEEE numbers are interpreted as 1.F x 2**exp, whereas the intermediate representation is 0.F x 2**exp. Which means we're off by one. */ - if (denormal) + if (real_isdenormal (r)) exp = 0; else exp = REAL_EXP (r) + 15 - 1; @@ -4843,7 +4848,6 @@ encode_arm_bfloat_half (const struct real_format *fmt, long *buf, { unsigned long image, sig, exp; unsigned long sign = r->sign; - bool denormal = real_isdenormal (r); image = sign << 15; sig = (r->sig[SIGSZ-1] >> (HOST_BITS_PER_LONG - 8)) & 0x7f; @@ -4880,7 +4884,7 @@ encode_arm_bfloat_half (const struct real_format *fmt, long *buf, break; case rvc_normal: - if (denormal) + if (real_isdenormal (r)) exp = 0; else exp = REAL_EXP (r) + 127 - 1; diff --git a/gcc/real.h b/gcc/real.h index 306e9593866..b14bcdd3fde 100644 --- a/gcc/real.h +++ b/gcc/real.h @@ -286,11 +286,12 @@ extern bool real_isnan (const REAL_VALUE_TYPE *); /* Determine whether a floating-point value X is a signaling NaN. */ extern bool real_issignaling_nan (const REAL_VALUE_TYPE *); -/* Determine whether a floating-point value X is a denormal. */ +/* Determine whether floating-point value R is a denormal. This + function is only valid for normalized values. */ inline bool -real_isdenormal (const REAL_VALUE_TYPE *r) +real_isdenormal (const REAL_VALUE_TYPE *r, machine_mode mode) { - return r->cl == rvc_normal && (r->sig[SIGSZ-1] & SIG_MSB) == 0; + return r->cl == rvc_normal && REAL_EXP (r) < REAL_MODE_FORMAT (mode)->emin; } /* Determine whether a floating-point value X is finite. */ diff --git a/gcc/value-range.cc b/gcc/value-range.cc index a855aaf626c..859c7fb4af9 100644 --- a/gcc/value-range.cc +++ b/gcc/value-range.cc @@ -266,15 +266,16 @@ frange::flush_denormals_to_zero () if (undefined_p () || known_isnan ()) return; + machine_mode mode = TYPE_MODE (type ()); // Flush [x, -DENORMAL] to [x, -0.0]. - if (real_isdenormal (&m_max) && real_isneg (&m_max)) + if (real_isdenormal (&m_max, mode) && real_isneg (&m_max)) { m_max = dconst0; if (HONOR_SIGNED_ZEROS (m_type)) m_max.sign = 1; } // Flush [+DENORMAL, x] to [+0.0, x]. - if (real_isdenormal (&m_min) && !real_isneg (&m_min)) + if (real_isdenormal (&m_min, mode) && !real_isneg (&m_min)) m_min = dconst0; } -- 2.38.1