Re: [PATCH v2 0/4] LoongArch: Add some floating-point operations

[Xi Ruoyao via Libc-alpha <libc-alpha@sourceware.org>]

[-- Attachment #1: Type: text/plain, Size: 3049 bytes --]

On Mon, 2022-11-14 at 10:41 +0800, tangxiaolin wrote:
> How about I do this work on Glibc?

[Moving the discussion to libc-alpha.]

Go for it.  I'm attaching my draft patches and you can use them as a
starting point.

rint change is trivial.  for lrint and llrint I'm not sure if we should
add USE_LRINTL_BUILTIN and USE_LRINTF128_BUILTIN (with zero value) as
well.  Likewise for logb.

scalbn is a little complicated: I'd prefer to expand M_SCALBN to
__builtin_scalbn directly instead of calling __scalbn (to avoid the
overhead calling a function with only two instructions) but it seems not
easy: some files calling M_SCALBN are compiled with -fmath-errno, with
which the compiler will refuse to expand __builtin_scalbn.

> 在 2022/11/12 下午3:08, Xi Ruoyao 写道:
> > On Wed, 2022-11-09 at 21:53 +0800, Xi Ruoyao wrote:
> > > These patches allow to expand the following builtins to floating
> > > point
> > > instructions for LoongArch:
> > > 
> > > - __builtin_rint{,f}
> > > - __builtin_{l,ll}rint{,f}
> > > - __builtin_{l,ll}floor{,f}
> > > - __builtin_{l,ll}ceil{,f}
> > > - __builtin_scalb{n,ln}{,f}
> > > - __builtin_logb{,f}
> > > 
> > > Bootstrapped and regtested on loongarch64-linux-gnu.  And a
> > > modified
> > > Glibc using the builtins for rint{,f}, {l,ll}rint{,f}, and
> > > logb{,f}
> > > also survived Glibc test suite.
> > > 
> > > Please review ASAP because GCC 13 stage 1 will end on Nov. 13th.
> > > 
> > > v1 -> v2: Only use ftint{rm,rp} instructions if floor and ceil are
> > > allowed to raise inexact exception.
> > > 
> > > Xi Ruoyao (4):
> > >    LoongArch: Rename frint_<fmt> to rint<mode>2
> > >    LoongArch: Add ftint{,rm,rp}.{w,l}.{s,d} instructions
> > >    LoongArch: Add fscaleb.{s,d} instructions as ldexp{sf,df}3
> > >    LoongArch: Add flogb.{s,d} instructions and expand logb{sf,df}2
> > > 
> > >   gcc/config/loongarch/loongarch.md             | 95
> > > ++++++++++++++++++-
> > >   gcc/testsuite/gcc.target/loongarch/flogb.c    | 18 ++++
> > >   gcc/testsuite/gcc.target/loongarch/frint.c    | 16 ++++
> > >   gcc/testsuite/gcc.target/loongarch/fscaleb.c  | 48 ++++++++++
> > >   .../gcc.target/loongarch/ftint-no-inexact.c   | 44 +++++++++
> > >   gcc/testsuite/gcc.target/loongarch/ftint.c    | 44 +++++++++
> > >   6 files changed, 261 insertions(+), 4 deletions(-)
> > >   create mode 100644 gcc/testsuite/gcc.target/loongarch/flogb.c
> > >   create mode 100644 gcc/testsuite/gcc.target/loongarch/frint.c
> > >   create mode 100644 gcc/testsuite/gcc.target/loongarch/fscaleb.c
> > >   create mode 100644 gcc/testsuite/gcc.target/loongarch/ftint-no-
> > > inexact.c
> > >   create mode 100644 gcc/testsuite/gcc.target/loongarch/ftint.c
> > > 
> > Pushed r13-3922.
> > 
> > I'll be busy in the following week.  Will do the work on Glibc side
> > after Nov. 20.
> > 
> 

-- 
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University

[-- Attachment #2: 0005-LoongArch-Use-__builtin_logb-f-with-GCC-13.patch --]
[-- Type: text/x-patch, Size: 799 bytes --]

From e8ab00c0f68f1d294432ddaf68c0c691ed37df19 Mon Sep 17 00:00:00 2001
From: Xi Ruoyao <xry111@xry111.site>
Date: Wed, 9 Nov 2022 02:02:00 +0800
Subject: [PATCH 5/5] LoongArch: Use __builtin_logb{,f} with GCC >= 13

---
 sysdeps/loongarch/fpu/math-use-builtins-logb.h | 7 +++++++
 1 file changed, 7 insertions(+)
 create mode 100644 sysdeps/loongarch/fpu/math-use-builtins-logb.h

diff --git a/sysdeps/loongarch/fpu/math-use-builtins-logb.h b/sysdeps/loongarch/fpu/math-use-builtins-logb.h
new file mode 100644
index 0000000000..70a9306dfa
--- /dev/null
+++ b/sysdeps/loongarch/fpu/math-use-builtins-logb.h
@@ -0,0 +1,7 @@
+#if __GNUC_PREREQ (13, 0)
+#  define USE_LOGB_BUILTIN 1
+#  define USE_LOGBF_BUILTIN 1
+#else
+#  define USE_LOGB_BUILTIN 0
+#  define USE_LOGBF_BUILTIN 0
+#endif
-- 
2.37.0


[-- Attachment #3: 0004-math-Allow-using-compiler-builtins-for-logb-f.patch --]
[-- Type: text/x-patch, Size: 2553 bytes --]

From a5b8dff144d01ecc5eb76a8e27f7a207a7200807 Mon Sep 17 00:00:00 2001
From: Xi Ruoyao <xry111@xry111.site>
Date: Wed, 9 Nov 2022 02:01:32 +0800
Subject: [PATCH 4/5] math: Allow using compiler builtins for logb{,f}

---
 sysdeps/generic/math-use-builtins-logb.h | 2 ++
 sysdeps/generic/math-use-builtins.h      | 1 +
 sysdeps/ieee754/dbl-64/s_logb.c          | 5 +++++
 sysdeps/ieee754/flt-32/s_logbf.c         | 5 +++++
 4 files changed, 13 insertions(+)
 create mode 100644 sysdeps/generic/math-use-builtins-logb.h

diff --git a/sysdeps/generic/math-use-builtins-logb.h b/sysdeps/generic/math-use-builtins-logb.h
new file mode 100644
index 0000000000..f8fc9ae7cb
--- /dev/null
+++ b/sysdeps/generic/math-use-builtins-logb.h
@@ -0,0 +1,2 @@
+#define USE_LOGB_BUILTIN 0
+#define USE_LOGBF_BUILTIN 0
diff --git a/sysdeps/generic/math-use-builtins.h b/sysdeps/generic/math-use-builtins.h
index 3acec1d538..a9cd510c2a 100644
--- a/sysdeps/generic/math-use-builtins.h
+++ b/sysdeps/generic/math-use-builtins.h
@@ -38,5 +38,6 @@
 #include <math-use-builtins-fmin.h>
 #include <math-use-builtins-fabs.h>
 #include <math-use-builtins-lrint.h>
+#include <math-use-builtins-logb.h>
 
 #endif /* MATH_USE_BUILTINS_H  */
diff --git a/sysdeps/ieee754/dbl-64/s_logb.c b/sysdeps/ieee754/dbl-64/s_logb.c
index 82cabd206a..a9b18bf97b 100644
--- a/sysdeps/ieee754/dbl-64/s_logb.c
+++ b/sysdeps/ieee754/dbl-64/s_logb.c
@@ -21,10 +21,14 @@
 #include <math_private.h>
 #include <libm-alias-double.h>
 #include <fix-int-fp-convert-zero.h>
+#include <math-use-builtins.h>
 
 double
 __logb (double x)
 {
+#if USE_LOGB_BUILTIN
+  return __builtin_logb (x);
+#else
   int64_t ix, ex;
 
   EXTRACT_WORDS64 (ix, x);
@@ -42,6 +46,7 @@ __logb (double x)
   if (FIX_INT_FP_CONVERT_ZERO && ex == 1023)
     return 0.0;
   return (double) (ex - 1023);
+#endif
 }
 #ifndef __logb
 libm_alias_double (__logb, logb)
diff --git a/sysdeps/ieee754/flt-32/s_logbf.c b/sysdeps/ieee754/flt-32/s_logbf.c
index a06f975797..cf58596c8f 100644
--- a/sysdeps/ieee754/flt-32/s_logbf.c
+++ b/sysdeps/ieee754/flt-32/s_logbf.c
@@ -16,10 +16,14 @@
 #include <math_private.h>
 #include <libm-alias-float.h>
 #include <fix-int-fp-convert-zero.h>
+#include <math-use-builtins.h>
 
 float
 __logbf (float x)
 {
+#if USE_LOGBF_BUILTIN
+  return __builtin_logbf (x);
+#else
   int32_t ix, rix;
 
   GET_FLOAT_WORD (ix, x);
@@ -37,5 +41,6 @@ __logbf (float x)
   if (FIX_INT_FP_CONVERT_ZERO && rix == 127)
     return 0.0f;
   return (float) (rix - 127);
+#endif
 }
 libm_alias_float (__logb, logb)
-- 
2.37.0


[-- Attachment #4: 0003-LoongArch-Use-__builtin_-l-ll-rint-f-with-GCC-13.patch --]
[-- Type: text/x-patch, Size: 951 bytes --]

From d8e948afe78222323f72fa1a40ff7e169f7c06cc Mon Sep 17 00:00:00 2001
From: Xi Ruoyao <xry111@xry111.site>
Date: Wed, 9 Nov 2022 01:18:52 +0800
Subject: [PATCH 3/5] LoongArch: Use __builtin_{l,ll}rint{,f} with GCC >= 13

---
 sysdeps/loongarch/fpu/math-use-builtins-lrint.h | 11 +++++++++++
 1 file changed, 11 insertions(+)
 create mode 100644 sysdeps/loongarch/fpu/math-use-builtins-lrint.h

diff --git a/sysdeps/loongarch/fpu/math-use-builtins-lrint.h b/sysdeps/loongarch/fpu/math-use-builtins-lrint.h
new file mode 100644
index 0000000000..0c8187d09e
--- /dev/null
+++ b/sysdeps/loongarch/fpu/math-use-builtins-lrint.h
@@ -0,0 +1,11 @@
+#if __GNUC_PREREQ (13, 0)
+#  define USE_LRINT_BUILTIN 1
+#  define USE_LRINTF_BUILTIN 1
+#  define USE_LLRINT_BUILTIN 1
+#  define USE_LLRINTF_BUILTIN 1
+#else
+#  define USE_LRINT_BUILTIN 0
+#  define USE_LRINTF_BUILTIN 0
+#  define USE_LLRINT_BUILTIN 0
+#  define USE_LLRINTF_BUILTIN 0
+#endif
-- 
2.37.0


[-- Attachment #5: 0002-math-Allow-using-compiler-builtins-for-l-ll-rint-f.patch --]
[-- Type: text/x-patch, Size: 4632 bytes --]

From dd83a647441d4f6137095bf7a37f75840cd051db Mon Sep 17 00:00:00 2001
From: Xi Ruoyao <xry111@xry111.site>
Date: Wed, 9 Nov 2022 01:18:11 +0800
Subject: [PATCH 2/5] math: Allow using compiler builtins for {l,ll}rint{,f}

---
 sysdeps/generic/math-use-builtins-lrint.h | 4 ++++
 sysdeps/generic/math-use-builtins.h       | 1 +
 sysdeps/ieee754/dbl-64/s_llrint.c         | 7 +++++++
 sysdeps/ieee754/dbl-64/s_lrint.c          | 7 +++++++
 sysdeps/ieee754/flt-32/s_llrintf.c        | 7 +++++++
 sysdeps/ieee754/flt-32/s_lrintf.c         | 7 +++++++
 6 files changed, 33 insertions(+)
 create mode 100644 sysdeps/generic/math-use-builtins-lrint.h

diff --git a/sysdeps/generic/math-use-builtins-lrint.h b/sysdeps/generic/math-use-builtins-lrint.h
new file mode 100644
index 0000000000..3159ba977a
--- /dev/null
+++ b/sysdeps/generic/math-use-builtins-lrint.h
@@ -0,0 +1,4 @@
+#define USE_LRINT_BUILTIN 0
+#define USE_LRINTF_BUILTIN 0
+#define USE_LLRINT_BUILTIN 0
+#define USE_LLRINTF_BUILTIN 0
diff --git a/sysdeps/generic/math-use-builtins.h b/sysdeps/generic/math-use-builtins.h
index 6bd424d900..3acec1d538 100644
--- a/sysdeps/generic/math-use-builtins.h
+++ b/sysdeps/generic/math-use-builtins.h
@@ -37,5 +37,6 @@
 #include <math-use-builtins-fmax.h>
 #include <math-use-builtins-fmin.h>
 #include <math-use-builtins-fabs.h>
+#include <math-use-builtins-lrint.h>
 
 #endif /* MATH_USE_BUILTINS_H  */
diff --git a/sysdeps/ieee754/dbl-64/s_llrint.c b/sysdeps/ieee754/dbl-64/s_llrint.c
index dc8d9948df..1c041e3b26 100644
--- a/sysdeps/ieee754/dbl-64/s_llrint.c
+++ b/sysdeps/ieee754/dbl-64/s_llrint.c
@@ -25,17 +25,23 @@
 #include <math_private.h>
 #include <libm-alias-double.h>
 #include <fix-fp-int-convert-overflow.h>
+#include <math-use-builtins.h>
 
+#if !USE_LLRINT_BUILTIN
 static const double two52[2] =
 {
   4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
  -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
 };
+#endif
 
 
 long long int
 __llrint (double x)
 {
+#if USE_LLRINT_BUILTIN
+  return __builtin_llrint (x);
+#else
   int32_t j0;
   uint32_t i1, i0;
   long long int result;
@@ -95,6 +101,7 @@ __llrint (double x)
     }
 
   return sx ? -result : result;
+#endif
 }
 
 libm_alias_double (__llrint, llrint)
diff --git a/sysdeps/ieee754/dbl-64/s_lrint.c b/sysdeps/ieee754/dbl-64/s_lrint.c
index d4272916cd..fdb2d86f3f 100644
--- a/sysdeps/ieee754/dbl-64/s_lrint.c
+++ b/sysdeps/ieee754/dbl-64/s_lrint.c
@@ -25,17 +25,23 @@
 #include <math_private.h>
 #include <libm-alias-double.h>
 #include <fix-fp-int-convert-overflow.h>
+#include <math-use-builtins.h>
 
+#if !USE_LRINT_BUILTIN
 static const double two52[2] =
 {
   4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
  -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
 };
+#endif
 
 
 long int
 __lrint (double x)
 {
+#if USE_LRINT_BUILTIN
+  return __builtin_lrint (x);
+#else
   int32_t j0;
   uint32_t i0, i1;
   double w;
@@ -119,6 +125,7 @@ __lrint (double x)
     }
 
   return sx ? -result : result;
+#endif
 }
 
 libm_alias_double (__lrint, lrint)
diff --git a/sysdeps/ieee754/flt-32/s_llrintf.c b/sysdeps/ieee754/flt-32/s_llrintf.c
index 226b8261d3..12654848b8 100644
--- a/sysdeps/ieee754/flt-32/s_llrintf.c
+++ b/sysdeps/ieee754/flt-32/s_llrintf.c
@@ -25,17 +25,23 @@
 #include <math_private.h>
 #include <libm-alias-float.h>
 #include <fix-fp-int-convert-overflow.h>
+#include <math-use-builtins.h>
 
+#if !USE_LLRINTF_BUILTIN
 static const float two23[2] =
 {
   8.3886080000e+06, /* 0x4B000000 */
  -8.3886080000e+06, /* 0xCB000000 */
 };
+#endif
 
 
 long long int
 __llrintf (float x)
 {
+#if USE_LLRINTF_BUILTIN
+  return __builtin_llrintf (x);
+#else
   int32_t j0;
   uint32_t i0;
   float w;
@@ -82,6 +88,7 @@ __llrintf (float x)
     }
 
   return sx ? -result : result;
+#endif
 }
 
 libm_alias_float (__llrint, llrint)
diff --git a/sysdeps/ieee754/flt-32/s_lrintf.c b/sysdeps/ieee754/flt-32/s_lrintf.c
index 7438b272b2..7b0ff994bd 100644
--- a/sysdeps/ieee754/flt-32/s_lrintf.c
+++ b/sysdeps/ieee754/flt-32/s_lrintf.c
@@ -25,17 +25,23 @@
 #include <math_private.h>
 #include <libm-alias-float.h>
 #include <fix-fp-int-convert-overflow.h>
+#include <math-use-builtins.h>
 
+#if !USE_LRINTF_BUILTIN
 static const float two23[2] =
 {
   8.3886080000e+06, /* 0x4B000000 */
  -8.3886080000e+06, /* 0xCB000000 */
 };
+#endif
 
 
 long int
 __lrintf (float x)
 {
+#if USE_LRINTF_BUILTIN
+  return __builtin_lrintf (x);
+#else
   int32_t j0;
   uint32_t i0;
   float w;
@@ -82,6 +88,7 @@ __lrintf (float x)
     }
 
   return sx ? -result : result;
+#endif
 }
 
 libm_alias_float (__lrint, lrint)
-- 
2.37.0


[-- Attachment #6: 0001-LoongArch-Use-__builtin_rint-f-with-GCC-13.patch --]
[-- Type: text/x-patch, Size: 862 bytes --]

From a8d6d6a05cf7cd3acbc5428ce7324ec3867be067 Mon Sep 17 00:00:00 2001
From: Xi Ruoyao <xry111@xry111.site>
Date: Wed, 9 Nov 2022 01:00:09 +0800
Subject: [PATCH 1/5] LoongArch: Use __builtin_rint{,f} with GCC >= 13

---
 sysdeps/loongarch/fpu/math-use-builtins-rint.h | 9 +++++++++
 1 file changed, 9 insertions(+)
 create mode 100644 sysdeps/loongarch/fpu/math-use-builtins-rint.h

diff --git a/sysdeps/loongarch/fpu/math-use-builtins-rint.h b/sysdeps/loongarch/fpu/math-use-builtins-rint.h
new file mode 100644
index 0000000000..cd91482f5f
--- /dev/null
+++ b/sysdeps/loongarch/fpu/math-use-builtins-rint.h
@@ -0,0 +1,9 @@
+#if __GNUC_PREREQ (13, 0)
+#  define USE_RINT_BUILTIN 1
+#  define USE_RINTF_BUILTIN 1
+#else
+#  define USE_RINT_BUILTIN 0
+#  define USE_RINTF_BUILTIN 0
+#endif
+#define USE_RINTL_BUILTIN 0
+#define USE_RINTF128_BUILTIN 0
-- 
2.37.0