https://github.com/wenju-he created
https://github.com/llvm/llvm-project/pull/157633
Remove the dependency on the libclc build-time configuration for
__clc_fp*_subnormals_supported. The check is now implemented with LLVM
intrinsics so it can be resolved during target lowering or at runtime.
Improve __clc_flush_denormal_if_not_supported implementation as well. It
doesn't use __clc_fp*_subnormals_supported which canonicalizes sNaN and thus
the new implementation is more foldable.
Remove cmake option ENABLE_RUNTIME_SUBNORMAL and related code.
Resolves #153148
>From 7e2d210d9c6cd20c342562a44c2e4d2cb238e229 Mon Sep 17 00:00:00 2001
From: Wenju He <wenju...@intel.com>
Date: Tue, 9 Sep 2025 11:05:02 +0200
Subject: [PATCH] [libclc] Refine __clc_fp*_subnormals_supported and
__clc_flush_denormal_if_not_supported
Remove the dependency on the libclc build-time configuration for
__clc_fp*_subnormals_supported. The check is now implemented with LLVM
intrinsics so it can be resolved during target lowering or at runtime.
Improve __clc_flush_denormal_if_not_supported implementation as well.
It doesn't use __clc_fp*_subnormals_supported which canonicalizes sNaN
and thus the new implementation is more foldable.
Remove cmake option ENABLE_RUNTIME_SUBNORMAL and related code.
Resolves #153148
Co-authored-by: Matt Arsenault <matthew.arsena...@amd.com>
---
libclc/CMakeLists.txt | 18 --------
.../include/clc/math/clc_subnormal_config.h | 1 -
libclc/clc/include/clc/math/math.h | 13 ++----
libclc/clc/lib/generic/SOURCES | 1 +
libclc/clc/lib/generic/math/clc_exp10.cl | 1 -
libclc/clc/lib/generic/math/clc_hypot.cl | 1 -
libclc/clc/lib/generic/math/clc_pow.cl | 1 -
libclc/clc/lib/generic/math/clc_pown.cl | 1 -
libclc/clc/lib/generic/math/clc_powr.cl | 1 -
libclc/clc/lib/generic/math/clc_remquo.cl | 1 -
.../lib/generic/math/clc_subnormal_config.cl | 46 +++++++++++++++++++
libclc/opencl/lib/clspv/SOURCES | 1 -
libclc/opencl/lib/clspv/subnormal_config.cl | 16 -------
libclc/opencl/lib/generic/SOURCES | 2 -
libclc/opencl/lib/generic/subnormal_config.cl | 18 --------
.../opencl/lib/generic/subnormal_disable.ll | 9 ----
.../lib/generic/subnormal_helper_func.ll | 16 -------
.../lib/generic/subnormal_use_default.ll | 9 ----
libclc/opencl/lib/spirv/SOURCES | 1 -
libclc/opencl/lib/spirv/subnormal_config.cl | 16 -------
20 files changed, 52 insertions(+), 121 deletions(-)
create mode 100644 libclc/clc/lib/generic/math/clc_subnormal_config.cl
delete mode 100644 libclc/opencl/lib/clspv/subnormal_config.cl
delete mode 100644 libclc/opencl/lib/generic/subnormal_config.cl
delete mode 100644 libclc/opencl/lib/generic/subnormal_disable.ll
delete mode 100644 libclc/opencl/lib/generic/subnormal_helper_func.ll
delete mode 100644 libclc/opencl/lib/generic/subnormal_use_default.ll
delete mode 100644 libclc/opencl/lib/spirv/subnormal_config.cl
diff --git a/libclc/CMakeLists.txt b/libclc/CMakeLists.txt
index c75f450d8d3ad..572556034e66c 100644
--- a/libclc/CMakeLists.txt
+++ b/libclc/CMakeLists.txt
@@ -41,8 +41,6 @@ set( LIBCLC_MIN_LLVM 3.9.0 )
set( LIBCLC_TARGETS_TO_BUILD "all"
CACHE STRING "Semicolon-separated list of libclc targets to build, or
'all'." )
-option( ENABLE_RUNTIME_SUBNORMAL "Enable runtime linking of subnormal
support." OFF )
-
option(
LIBCLC_USE_SPIRV_BACKEND "Build SPIR-V targets with the SPIR-V backend." OFF
)
@@ -231,19 +229,6 @@ set( tahiti_aliases pitcairn verde oland hainan bonaire
kabini kaveri hawaii
configure_file( libclc.pc.in libclc.pc @ONLY )
install( FILES ${CMAKE_CURRENT_BINARY_DIR}/libclc.pc DESTINATION
"${CMAKE_INSTALL_DATADIR}/pkgconfig" )
-if( ENABLE_RUNTIME_SUBNORMAL )
- foreach( file IN ITEMS subnormal_use_default subnormal_disable )
- link_bc(
- TARGET ${file}
- INPUTS ${CMAKE_CURRENT_SOURCE_DIR}/opencl/lib/generic/${file}.ll
- )
- install(
- FILES $<TARGET_PROPERTY:${file},TARGET_FILE>
- DESTINATION "${CMAKE_INSTALL_DATADIR}/clc"
- )
- endforeach()
-endif()
-
find_package( Python3 REQUIRED COMPONENTS Interpreter )
file( TO_CMAKE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/utils/gen_convert.py
script_loc )
add_custom_command(
@@ -371,9 +356,6 @@ foreach( t ${LIBCLC_TARGETS_TO_BUILD} )
list( APPEND opencl_gen_files clspv-convert.cl )
else()
list( APPEND opencl_gen_files convert.cl )
- if ( NOT ENABLE_RUNTIME_SUBNORMAL )
- list( APPEND opencl_lib_files
opencl/lib/generic/subnormal_use_default.ll )
- endif()
endif()
endif()
diff --git a/libclc/clc/include/clc/math/clc_subnormal_config.h
b/libclc/clc/include/clc/math/clc_subnormal_config.h
index 14693ed01e033..e44ec1958b101 100644
--- a/libclc/clc/include/clc/math/clc_subnormal_config.h
+++ b/libclc/clc/include/clc/math/clc_subnormal_config.h
@@ -10,7 +10,6 @@
#include <clc/clcfunc.h>
-_CLC_DECL bool __clc_subnormals_disabled();
_CLC_DECL bool __clc_fp16_subnormals_supported();
_CLC_DECL bool __clc_fp32_subnormals_supported();
_CLC_DECL bool __clc_fp64_subnormals_supported();
diff --git a/libclc/clc/include/clc/math/math.h
b/libclc/clc/include/clc/math/math.h
index c2647f66b4006..2db5d187c88ce 100644
--- a/libclc/clc/include/clc/math/math.h
+++ b/libclc/clc/include/clc/math/math.h
@@ -11,7 +11,6 @@
#include <clc/clc_as_type.h>
#include <clc/clcfunc.h>
-#include <clc/math/clc_subnormal_config.h>
#define SNAN 0x001
#define QNAN 0x002
@@ -66,13 +65,11 @@ bool __attribute__((noinline))
__clc_runtime_has_hw_fma32(void);
#define LOG_MAGIC_NUM_SP32 (1 + NUMEXPBITS_SP32 - EXPBIAS_SP32)
_CLC_OVERLOAD _CLC_INLINE float __clc_flush_denormal_if_not_supported(float x)
{
- int ix = __clc_as_int(x);
- if (!__clc_fp32_subnormals_supported() && ((ix & EXPBITS_SP32) == 0) &&
- ((ix & MANTBITS_SP32) != 0)) {
- ix &= SIGNBIT_SP32;
- x = __clc_as_float(ix);
- }
- return x;
+ // Avoid calling __clc_fp32_subnormals_supported here: it uses
+ // llvm.canonicalize, which quiets sNaN.
+ return __builtin_fabsf(x) < 0x1p-149f
+ ? __builtin_elementwise_copysign(0.0f, x)
+ : x;
}
#ifdef cl_khr_fp64
diff --git a/libclc/clc/lib/generic/SOURCES b/libclc/clc/lib/generic/SOURCES
index ee4f771799e8e..4a6dadc702033 100644
--- a/libclc/clc/lib/generic/SOURCES
+++ b/libclc/clc/lib/generic/SOURCES
@@ -137,6 +137,7 @@ math/clc_sincos_helpers.cl
math/clc_sinh.cl
math/clc_sinpi.cl
math/clc_sqrt.cl
+math/clc_subnormal_config.cl
math/clc_sw_fma.cl
math/clc_tables.cl
math/clc_tan.cl
diff --git a/libclc/clc/lib/generic/math/clc_exp10.cl
b/libclc/clc/lib/generic/math/clc_exp10.cl
index 0c394ee19475a..fb33367851fda 100644
--- a/libclc/clc/lib/generic/math/clc_exp10.cl
+++ b/libclc/clc/lib/generic/math/clc_exp10.cl
@@ -11,7 +11,6 @@
#include <clc/math/clc_fma.h>
#include <clc/math/clc_ldexp.h>
#include <clc/math/clc_mad.h>
-#include <clc/math/clc_subnormal_config.h>
#include <clc/math/math.h>
#include <clc/math/tables.h>
#include <clc/relational/clc_isnan.h>
diff --git a/libclc/clc/lib/generic/math/clc_hypot.cl
b/libclc/clc/lib/generic/math/clc_hypot.cl
index c934ab29da91b..fd046bccaed51 100644
--- a/libclc/clc/lib/generic/math/clc_hypot.cl
+++ b/libclc/clc/lib/generic/math/clc_hypot.cl
@@ -12,7 +12,6 @@
#include <clc/math/clc_fma.h>
#include <clc/math/clc_mad.h>
#include <clc/math/clc_sqrt.h>
-#include <clc/math/clc_subnormal_config.h>
#include <clc/math/math.h>
#include <clc/relational/clc_isnan.h>
#include <clc/shared/clc_clamp.h>
diff --git a/libclc/clc/lib/generic/math/clc_pow.cl
b/libclc/clc/lib/generic/math/clc_pow.cl
index 70d3d614a8d36..c20d3829ea076 100644
--- a/libclc/clc/lib/generic/math/clc_pow.cl
+++ b/libclc/clc/lib/generic/math/clc_pow.cl
@@ -12,7 +12,6 @@
#include <clc/math/clc_fma.h>
#include <clc/math/clc_ldexp.h>
#include <clc/math/clc_mad.h>
-#include <clc/math/clc_subnormal_config.h>
#include <clc/math/math.h>
#include <clc/math/tables.h>
#include <clc/relational/clc_select.h>
diff --git a/libclc/clc/lib/generic/math/clc_pown.cl
b/libclc/clc/lib/generic/math/clc_pown.cl
index 5aa9560174b99..cfc415753fd1a 100644
--- a/libclc/clc/lib/generic/math/clc_pown.cl
+++ b/libclc/clc/lib/generic/math/clc_pown.cl
@@ -12,7 +12,6 @@
#include <clc/math/clc_fma.h>
#include <clc/math/clc_ldexp.h>
#include <clc/math/clc_mad.h>
-#include <clc/math/clc_subnormal_config.h>
#include <clc/math/math.h>
#include <clc/math/tables.h>
#include <clc/relational/clc_select.h>
diff --git a/libclc/clc/lib/generic/math/clc_powr.cl
b/libclc/clc/lib/generic/math/clc_powr.cl
index 0556ec97d6f3c..c35a3e2c382c5 100644
--- a/libclc/clc/lib/generic/math/clc_powr.cl
+++ b/libclc/clc/lib/generic/math/clc_powr.cl
@@ -12,7 +12,6 @@
#include <clc/math/clc_fma.h>
#include <clc/math/clc_ldexp.h>
#include <clc/math/clc_mad.h>
-#include <clc/math/clc_subnormal_config.h>
#include <clc/math/math.h>
#include <clc/math/tables.h>
#include <clc/relational/clc_select.h>
diff --git a/libclc/clc/lib/generic/math/clc_remquo.cl
b/libclc/clc/lib/generic/math/clc_remquo.cl
index fd83ead06d89a..cdebe4922baa0 100644
--- a/libclc/clc/lib/generic/math/clc_remquo.cl
+++ b/libclc/clc/lib/generic/math/clc_remquo.cl
@@ -12,7 +12,6 @@
#include <clc/math/clc_floor.h>
#include <clc/math/clc_fma.h>
#include <clc/math/clc_ldexp.h>
-#include <clc/math/clc_subnormal_config.h>
#include <clc/math/clc_trunc.h>
#include <clc/math/math.h>
#include <clc/shared/clc_max.h>
diff --git a/libclc/clc/lib/generic/math/clc_subnormal_config.cl
b/libclc/clc/lib/generic/math/clc_subnormal_config.cl
new file mode 100644
index 0000000000000..6be6eb44ae4f4
--- /dev/null
+++ b/libclc/clc/lib/generic/math/clc_subnormal_config.cl
@@ -0,0 +1,46 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 <clc/internal/clc.h>
+#include <clc/math/clc_subnormal_config.h>
+
+#ifdef cl_khr_fp16
+#pragma OPENCL EXTENSION cl_khr_fp16 : enable
+_CLC_DEF bool __clc_fp16_subnormals_supported() {
+#ifdef CLC_SPIRV
+ // SPIR-V doesn't support llvm.canonicalize for now.
+ return false;
+#else
+ return !__builtin_isfpclass(__builtin_canonicalizef(0x1p-24h),
+ __FPCLASS_POSZERO);
+#endif
+}
+#endif // cl_khr_fp16
+
+_CLC_DEF bool __clc_fp32_subnormals_supported() {
+#ifdef CLC_SPIRV
+ // SPIR-V doesn't support llvm.canonicalize for now.
+ return false;
+#else
+ return !__builtin_isfpclass(__builtin_canonicalizef(0x1p-149f),
+ __FPCLASS_POSZERO);
+#endif
+}
+
+#ifdef cl_khr_fp64
+#pragma OPENCL EXTENSION cl_khr_fp64 : enable
+_CLC_DEF bool __clc_fp64_subnormals_supported() {
+#ifdef CLC_SPIRV
+ // SPIR-V doesn't support llvm.canonicalize for now.
+ return false;
+#else
+ return !__builtin_isfpclass(__builtin_canonicalizef(0x1p-1074),
+ __FPCLASS_POSZERO);
+#endif
+}
+#endif // cl_khr_fp64
diff --git a/libclc/opencl/lib/clspv/SOURCES b/libclc/opencl/lib/clspv/SOURCES
index 0a142ed3e6043..3d9f871ff57ca 100644
--- a/libclc/opencl/lib/clspv/SOURCES
+++ b/libclc/opencl/lib/clspv/SOURCES
@@ -1,6 +1,5 @@
math/fma.cl
shared/vstore_half.cl
-subnormal_config.cl
../generic/geometric/distance.cl
../generic/geometric/length.cl
../generic/math/acos.cl
diff --git a/libclc/opencl/lib/clspv/subnormal_config.cl
b/libclc/opencl/lib/clspv/subnormal_config.cl
deleted file mode 100644
index 114aabb2e9435..0000000000000
--- a/libclc/opencl/lib/clspv/subnormal_config.cl
+++ /dev/null
@@ -1,16 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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 <clc/math/clc_subnormal_config.h>
-#include <clc/opencl/opencl-base.h>
-
-_CLC_DEF bool __clc_fp16_subnormals_supported() { return false; }
-
-_CLC_DEF bool __clc_fp32_subnormals_supported() { return false; }
-
-_CLC_DEF bool __clc_fp64_subnormals_supported() { return false; }
diff --git a/libclc/opencl/lib/generic/SOURCES
b/libclc/opencl/lib/generic/SOURCES
index 61757efbcaad7..410fbdee2c71f 100644
--- a/libclc/opencl/lib/generic/SOURCES
+++ b/libclc/opencl/lib/generic/SOURCES
@@ -1,5 +1,3 @@
-subnormal_config.cl
-subnormal_helper_func.ll
async/async_work_group_copy.cl
async/async_work_group_strided_copy.cl
async/prefetch.cl
diff --git a/libclc/opencl/lib/generic/subnormal_config.cl
b/libclc/opencl/lib/generic/subnormal_config.cl
deleted file mode 100644
index aa2e30935e5f0..0000000000000
--- a/libclc/opencl/lib/generic/subnormal_config.cl
+++ /dev/null
@@ -1,18 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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 <clc/math/clc_subnormal_config.h>
-#include <clc/opencl/opencl-base.h>
-
-_CLC_DEF bool __clc_fp16_subnormals_supported() { return false; }
-
-_CLC_DEF bool __clc_fp32_subnormals_supported() { return false; }
-
-_CLC_DEF bool __clc_fp64_subnormals_supported() {
- return !__clc_subnormals_disabled();
-}
diff --git a/libclc/opencl/lib/generic/subnormal_disable.ll
b/libclc/opencl/lib/generic/subnormal_disable.ll
deleted file mode 100644
index 732d09ff09ab4..0000000000000
--- a/libclc/opencl/lib/generic/subnormal_disable.ll
+++ /dev/null
@@ -1,9 +0,0 @@
-;;===----------------------------------------------------------------------===;;
-;
-; 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
-;
-;;===----------------------------------------------------------------------===;;
-
-@__CLC_SUBNORMAL_DISABLE = unnamed_addr constant i1 true
diff --git a/libclc/opencl/lib/generic/subnormal_helper_func.ll
b/libclc/opencl/lib/generic/subnormal_helper_func.ll
deleted file mode 100644
index 03beecf979260..0000000000000
--- a/libclc/opencl/lib/generic/subnormal_helper_func.ll
+++ /dev/null
@@ -1,16 +0,0 @@
-;;===----------------------------------------------------------------------===;;
-;
-; 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
-;
-;;===----------------------------------------------------------------------===;;
-
-@__CLC_SUBNORMAL_DISABLE = external global i1
-
-define i1 @__clc_subnormals_disabled() #0 {
- %disable = load i1, i1* @__CLC_SUBNORMAL_DISABLE
- ret i1 %disable
-}
-
-attributes #0 = { alwaysinline }
diff --git a/libclc/opencl/lib/generic/subnormal_use_default.ll
b/libclc/opencl/lib/generic/subnormal_use_default.ll
deleted file mode 100644
index c648cc0a8aded..0000000000000
--- a/libclc/opencl/lib/generic/subnormal_use_default.ll
+++ /dev/null
@@ -1,9 +0,0 @@
-;;===----------------------------------------------------------------------===;;
-;
-; 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
-;
-;;===----------------------------------------------------------------------===;;
-
-@__CLC_SUBNORMAL_DISABLE = unnamed_addr constant i1 false
diff --git a/libclc/opencl/lib/spirv/SOURCES b/libclc/opencl/lib/spirv/SOURCES
index 0aa923978e9f1..aa7fcee0c4f4a 100644
--- a/libclc/opencl/lib/spirv/SOURCES
+++ b/libclc/opencl/lib/spirv/SOURCES
@@ -1,4 +1,3 @@
-subnormal_config.cl
../generic/async/async_work_group_strided_copy.cl
../generic/async/wait_group_events.cl
../generic/common/degrees.cl
diff --git a/libclc/opencl/lib/spirv/subnormal_config.cl
b/libclc/opencl/lib/spirv/subnormal_config.cl
deleted file mode 100644
index 114aabb2e9435..0000000000000
--- a/libclc/opencl/lib/spirv/subnormal_config.cl
+++ /dev/null
@@ -1,16 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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 <clc/math/clc_subnormal_config.h>
-#include <clc/opencl/opencl-base.h>
-
-_CLC_DEF bool __clc_fp16_subnormals_supported() { return false; }
-
-_CLC_DEF bool __clc_fp32_subnormals_supported() { return false; }
-
-_CLC_DEF bool __clc_fp64_subnormals_supported() { return false; }
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