[libc] Add `lgamma` and `lgamma_r` stubs for the GPU #102019

jhuber6 · 2024-08-05T17:11:12Z

Summary:
These functions are used by the implementation in libc++ and
cause a lot of tests to fail. For now we provide these through the
vendor abstraction until we have a real version. The NVPTX version
doesn't even update the output correctly so these are just temporary.

llvmbot · 2024-08-05T17:17:15Z

@llvm/pr-subscribers-backend-amdgpu

@llvm/pr-subscribers-libc

Author: Joseph Huber (jhuber6)

Changes

Summary:
These functions are used by the <random> implementation in libc++ and
cause a lot of tests to fail. For now we provide these through the
vendor abstraction until we have a real version. The NVPTX version
doesn't even update the output correctly so these are just temporary.

Full diff: https://github.com/llvm/llvm-project/pull/102019.diff

14 Files Affected:

(modified) libc/config/gpu/entrypoints.txt (+2)
(modified) libc/newhdrgen/yaml/math.yaml (+39)
(modified) libc/spec/stdc.td (+8)
(modified) libc/src/math/CMakeLists.txt (+2)
(modified) libc/src/math/amdgpu/CMakeLists.txt (+24)
(modified) libc/src/math/amdgpu/declarations.h (+2)
(added) libc/src/math/amdgpu/lgamma.cpp (+19)
(added) libc/src/math/amdgpu/lgamma_r.cpp (+24)
(added) libc/src/math/lgamma.h (+21)
(added) libc/src/math/lgamma_r.h (+20)
(modified) libc/src/math/nvptx/CMakeLists.txt (+24)
(modified) libc/src/math/nvptx/declarations.h (+1)
(added) libc/src/math/nvptx/lgamma.cpp (+20)
(added) libc/src/math/nvptx/lgamma_r.cpp (+23)

diff --git a/libc/config/gpu/entrypoints.txt b/libc/config/gpu/entrypoints.txt
index 8d29e7e2e253b..c70dc08490cef 100644
--- a/libc/config/gpu/entrypoints.txt
+++ b/libc/config/gpu/entrypoints.txt
@@ -349,6 +349,8 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.tanhf
     libc.src.math.tgamma
     libc.src.math.tgammaf
+    libc.src.math.lgamma
+    libc.src.math.lgamma_r
     libc.src.math.trunc
     libc.src.math.truncf
 )
diff --git a/libc/newhdrgen/yaml/math.yaml b/libc/newhdrgen/yaml/math.yaml
index ce562c653a6d2..1172184991122 100644
--- a/libc/newhdrgen/yaml/math.yaml
+++ b/libc/newhdrgen/yaml/math.yaml
@@ -2153,3 +2153,42 @@ functions:
       - type: int
       - type: unsigned int
     guard: LIBC_TYPES_HAS_FLOAT128
+  - name: lgamma
+    standards: 
+      - stdc
+    return_type: double
+    arguments:
+      - type: double
+  - name: lgammaf
+    standards: 
+      - stdc
+    return_type: float
+    arguments:
+      - type: float
+  - name: lgammal
+    standards: 
+      - stdc
+    return_type: long double
+    arguments:
+      - type: long double
+  - name: lgamma_r
+    standards: 
+      - stdc
+    return_type: double
+    arguments:
+      - type: double
+      - type: int *
+  - name: lgammaf_r
+    standards: 
+      - stdc
+    return_type: float
+    arguments:
+      - type: float
+      - type: int *
+  - name: lgammal_r
+    standards: 
+      - stdc
+    return_type: long double
+    arguments:
+      - type: long double
+      - type: int *
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 3f68eeb7853ad..623b0449d1e8a 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -767,6 +767,14 @@ def StdC : StandardSpec<"stdc"> {
           GuardedFunctionSpec<"f16divf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
 
           GuardedFunctionSpec<"f16sqrtf128", RetValSpec<Float16Type>, [ArgSpec<Float128Type>], "LIBC_TYPES_HAS_FLOAT16_AND_FLOAT128">,
+
+          FunctionSpec<"lgamma", RetValSpec<DoubleType>, [ArgSpec<DoubleType>]>,
+          FunctionSpec<"lgammaf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
+          FunctionSpec<"lgammal", RetValSpec<LongDoubleType>, [ArgSpec<LongDoubleType>]>,
+
+          FunctionSpec<"lgamma_r", RetValSpec<DoubleType>, [ArgSpec<DoubleType, IntPtr>]>,
+          FunctionSpec<"lgammaf_r", RetValSpec<FloatType>, [ArgSpec<FloatType, IntPtr>]>,
+          FunctionSpec<"lgammal_r", RetValSpec<LongDoubleType>, [ArgSpec<LongDoubleType, IntPtr>]>,
       ]
   >;
 
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index e513d72260fb1..aec94d41ad086 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -448,6 +448,8 @@ add_math_entrypoint_object(tanhf)
 
 add_math_entrypoint_object(tgamma)
 add_math_entrypoint_object(tgammaf)
+add_math_entrypoint_object(lgamma)
+add_math_entrypoint_object(lgamma_r)
 
 add_math_entrypoint_object(totalorder)
 add_math_entrypoint_object(totalorderf)
diff --git a/libc/src/math/amdgpu/CMakeLists.txt b/libc/src/math/amdgpu/CMakeLists.txt
index 7f80f688a2c4b..659acb2868fd7 100644
--- a/libc/src/math/amdgpu/CMakeLists.txt
+++ b/libc/src/math/amdgpu/CMakeLists.txt
@@ -527,3 +527,27 @@ add_entrypoint_object(
     -O2
   VENDOR
 )
+
+add_entrypoint_object(
+  lgamma
+  SRCS
+    lgamma.cpp
+  HDRS
+    ../lgamma.h
+  COMPILE_OPTIONS
+    ${bitcode_link_flags}
+    -O2
+  VENDOR
+)
+
+add_entrypoint_object(
+  lgamma_r
+  SRCS
+    lgamma_r.cpp
+  HDRS
+    ../lgamma_r.h
+  COMPILE_OPTIONS
+    ${bitcode_link_flags}
+    -O2
+  VENDOR
+)
diff --git a/libc/src/math/amdgpu/declarations.h b/libc/src/math/amdgpu/declarations.h
index 98c14ee43cd19..88e2201521b67 100644
--- a/libc/src/math/amdgpu/declarations.h
+++ b/libc/src/math/amdgpu/declarations.h
@@ -82,6 +82,8 @@ float __ocml_remquo_f32(float, float, gpu::Private<int> *);
 double __ocml_remquo_f64(double, double, gpu::Private<int> *);
 double __ocml_tgamma_f64(double);
 float __ocml_tgamma_f32(float);
+double __ocml_lgamma_f64(double);
+double __ocml_lgamma_r_f64(double, gpu::Private<int> *);
 }
 
 } // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/math/amdgpu/lgamma.cpp b/libc/src/math/amdgpu/lgamma.cpp
new file mode 100644
index 0000000000000..acff4c76734e1
--- /dev/null
+++ b/libc/src/math/amdgpu/lgamma.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of the lgamma function for GPU ---------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/lgamma.h"
+#include "src/__support/common.h"
+
+#include "declarations.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(double, lgamma, (double x)) { return __ocml_lgamma_f64(x); }
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/math/amdgpu/lgamma_r.cpp b/libc/src/math/amdgpu/lgamma_r.cpp
new file mode 100644
index 0000000000000..0a79988d66e30
--- /dev/null
+++ b/libc/src/math/amdgpu/lgamma_r.cpp
@@ -0,0 +1,24 @@
+//===-- Implementation of the lgamma_r function for GPU -------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/lgamma_r.h"
+#include "src/__support/common.h"
+
+#include "declarations.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(double, lgamma_r, (double x, int *signp)) {
+  int tmp = *signp;
+  double r = __ocml_lgamma_r_f64(x, (gpu::Private<int> *)&tmp);
+  *signp = tmp;
+  return r;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/math/lgamma.h b/libc/src/math/lgamma.h
new file mode 100644
index 0000000000000..603486765ec39
--- /dev/null
+++ b/libc/src/math/lgamma.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for lgamma ------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_MATH_LGAMMA_H
+#define LLVM_LIBC_SRC_MATH_LGAMMA_H
+
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+double lgamma(double x);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_MATH_LGAMMA_H
+
diff --git a/libc/src/math/lgamma_r.h b/libc/src/math/lgamma_r.h
new file mode 100644
index 0000000000000..1ca6b94c86bb4
--- /dev/null
+++ b/libc/src/math/lgamma_r.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for lgamma_r-----------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_MATH_LGAMMA_R_H
+#define LLVM_LIBC_SRC_MATH_LGAMMA_R_H
+
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+double lgamma_r(double x, int *signp);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_MATH_LGAMMA_R_H
diff --git a/libc/src/math/nvptx/CMakeLists.txt b/libc/src/math/nvptx/CMakeLists.txt
index 97da80b3dbaa1..a7d546e4f1df1 100644
--- a/libc/src/math/nvptx/CMakeLists.txt
+++ b/libc/src/math/nvptx/CMakeLists.txt
@@ -480,3 +480,27 @@ add_entrypoint_object(
     -O2
   VENDOR
 )
+
+add_entrypoint_object(
+  lgamma
+  SRCS
+    lgamma.cpp
+  HDRS
+    ../lgamma.h
+  COMPILE_OPTIONS
+    ${bitcode_link_flags}
+    -O2
+  VENDOR
+)
+
+add_entrypoint_object(
+  lgamma_r
+  SRCS
+    lgamma_r.cpp
+  HDRS
+    ../lgamma_r.h
+  COMPILE_OPTIONS
+    ${bitcode_link_flags}
+    -O2
+  VENDOR
+)
diff --git a/libc/src/math/nvptx/declarations.h b/libc/src/math/nvptx/declarations.h
index 7bfa934c0142d..6f0bcfe7dce0f 100644
--- a/libc/src/math/nvptx/declarations.h
+++ b/libc/src/math/nvptx/declarations.h
@@ -86,6 +86,7 @@ double __nv_remquo(double, double, int *);
 float __nv_remquof(float, float, int *);
 double __nv_tgamma(double);
 float __nv_tgammaf(float);
+float __nv_lgamma(double);
 }
 
 } // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/math/nvptx/lgamma.cpp b/libc/src/math/nvptx/lgamma.cpp
new file mode 100644
index 0000000000000..012ccd35bf939
--- /dev/null
+++ b/libc/src/math/nvptx/lgamma.cpp
@@ -0,0 +1,20 @@
+//===-- Implementation of the lgamma function for GPU ---------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/lgamma.h"
+#include "src/__support/common.h"
+
+#include "declarations.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(double, lgamma, (double x)) { return __nv_lgamma(x); }
+
+} // namespace LIBC_NAMESPACE_DECL
+
diff --git a/libc/src/math/nvptx/lgamma_r.cpp b/libc/src/math/nvptx/lgamma_r.cpp
new file mode 100644
index 0000000000000..aa0a7b9a4b8b9
--- /dev/null
+++ b/libc/src/math/nvptx/lgamma_r.cpp
@@ -0,0 +1,23 @@
+//===-- Implementation of the lgamma_r function for GPU -------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/lgamma_r.h"
+#include "src/__support/common.h"
+
+#include "declarations.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(double, lgamma_r, (double x, int *signp)) {
+  // The NVPTX device library does not export this, just pretend for now.
+  *signp = -1;
+  return __nv_lgamma(x);
+}
+
+} // namespace LIBC_NAMESPACE_DECL

github-actions · 2024-08-05T17:19:15Z

✅ With the latest revision this PR passed the C/C++ code formatter.

overmighty · 2024-08-05T17:17:17Z

libc/src/math/CMakeLists.txt

+add_math_entrypoint_object(lgamma)
+add_math_entrypoint_object(lgamma_r)


Nit: only type variants of the same function are grouped together (except a few exceptions that should be fixed), so tgamma*, lgamma* and lgamma_r* should be in three separate groups. Definitions are also sorted alphabetically, by function prefix/base name without type suffix.

overmighty · 2024-08-05T17:18:57Z

libc/src/math/nvptx/lgamma_r.cpp

+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(double, lgamma_r, (double x, int *signp)) {
+  // The NVPTX device library does not export this, just pretend for now.


Nit: maybe prefix this comment with TODO: so that IDEs and other tools can recognize it.

lntue · 2024-08-05T19:13:49Z

libc/src/math/nvptx/lgamma_r.cpp

+
+LLVM_LIBC_FUNCTION(double, lgamma_r, (double x, int *signp)) {
+  // The NVPTX device library does not export this, just pretend for now.
+  *signp = -1;


double result = __nv_lgamma(x); *signp = (result < 0.0) ? -1 : 1; return result;

lntue · 2024-08-05T19:16:26Z

libc/newhdrgen/yaml/math.yaml

+      - type: long double
+  - name: lgamma_r
+    standards: 
+      - stdc


*gamma_r functions are POSIX extensions?

I think it's a glibc extension actually.

lntue · 2024-08-05T19:16:54Z

libc/spec/stdc.td

+          FunctionSpec<"lgammaf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
+          FunctionSpec<"lgammal", RetValSpec<LongDoubleType>, [ArgSpec<LongDoubleType>]>,
+
+          FunctionSpec<"lgamma_r", RetValSpec<DoubleType>, [ArgSpec<DoubleType, IntPtr>]>,


*gamma_r functions are POSIX extensions?

The lgamma() functions are specified in C99 and POSIX.1-2001. signgam is specified in POSIX.1-2001, but not in C99. The lgamma_r() functions are nonstandard, but present on several other systems.

No standard lol.

Summary: These functions are used by the <random> implementation in libc++ and cause a lot of tests to fail. For now we provide these through the vendor abstraction until we have a real version. The NVPTX version doesn't even update the output correctly so these are just temporary.

overmighty · 2024-08-06T11:55:30Z

This broke the Buildbot builds while the Buildbot master was down. See https://lab.llvm.org/buildbot/#/builders/71/builds/3672 for example.

overmighty · 2024-08-06T12:43:02Z

This broke the Buildbot builds while the Buildbot master was down. See https://lab.llvm.org/buildbot/#/builders/71/builds/3672 for example.

Fixed by d798d3b.

jhuber6 requested review from lntue, michaelrj-google, overmighty and SchrodingerZhu August 5, 2024 17:11

llvmbot added backend:AMDGPU libc labels Aug 5, 2024

jhuber6 removed the backend:AMDGPU label Aug 5, 2024

overmighty reviewed Aug 5, 2024

View reviewed changes

jhuber6 force-pushed the lgamma branch from 2d895be to 20f6ee0 Compare August 5, 2024 17:22

llvmbot added the backend:AMDGPU label Aug 5, 2024

lntue reviewed Aug 5, 2024

View reviewed changes

jhuber6 force-pushed the lgamma branch from 20f6ee0 to dffa236 Compare August 5, 2024 19:23

jhuber6 force-pushed the lgamma branch from dffa236 to 96d71f5 Compare August 5, 2024 19:28

lntue approved these changes Aug 5, 2024

View reviewed changes

jhuber6 merged commit 88d2884 into llvm:main Aug 5, 2024
4 of 5 checks passed

jhuber6 deleted the lgamma branch October 14, 2024 19:20

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		add_math_entrypoint_object(lgamma)
		add_math_entrypoint_object(lgamma_r)

[libc] Add lgamma and lgamma_r stubs for the GPU #102019

[libc] Add lgamma and lgamma_r stubs for the GPU #102019

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