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1 //===-- AMDGPU specific platform definitions for math support -------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef LLVM_LIBC_SRC_MATH_AMDGPU_PLATFORM_H
10 #define LLVM_LIBC_SRC_MATH_AMDGPU_PLATFORM_H
11 
12 #include "src/__support/macros/attributes.h"
13 
14 #include <stdint.h>
15 
16 namespace LIBC_NAMESPACE {
17 
18 // The ROCm device library uses control globals to alter codegen for the
19 // different targets. To avoid needing to link them in manually we simply
20 // define them here.
21 extern "C" {
22 
23 // Disable unsafe math optimizations in the implementation.
24 extern const LIBC_INLINE_VAR uint8_t __oclc_unsafe_math_opt = 0;
25 
26 // Disable denormalization at zero optimizations in the implementation.
27 extern const LIBC_INLINE_VAR uint8_t __oclc_daz_opt = 0;
28 
29 // Disable rounding optimizations for 32-bit square roots.
30 extern const LIBC_INLINE_VAR uint8_t __oclc_correctly_rounded_sqrt32 = 1;
31 
32 // Disable finite math optimizations.
33 extern const LIBC_INLINE_VAR uint8_t __oclc_finite_only_opt = 0;
34 
35 // Set the ISA value to a high enough value that the ROCm device library math
36 // functions will assume we have fast FMA operations among other features. This
37 // is determined to be safe on all targets by looking at the source code.
38 // https://github.com/ROCm/ROCm-Device-Libs/blob/amd-stg-open/ocml/src/opts.h
39 extern const LIBC_INLINE_VAR uint32_t __oclc_ISA_version = 9000;
40 }
41 
42 // These aliases cause clang to emit the control constants with ODR linkage.
43 // This allows us to link against the symbols without preventing them from being
44 // optimized out or causing symbol collisions.
45 [[gnu::alias("__oclc_unsafe_math_opt")]] const uint8_t __oclc_unsafe_math_opt__;
46 [[gnu::alias("__oclc_daz_opt")]] const uint8_t __oclc_daz_opt__;
47 [[gnu::alias("__oclc_correctly_rounded_sqrt32")]] const uint8_t
48     __oclc_correctly_rounded_sqrt32__;
49 [[gnu::alias("__oclc_finite_only_opt")]] const uint8_t __oclc_finite_only_opt__;
50 [[gnu::alias("__oclc_ISA_version")]] const uint32_t __oclc_ISA_version__;
51 
52 } // namespace LIBC_NAMESPACE
53 
54 #endif // LLVM_LIBC_SRC_MATH_AMDGPU_PLATFORM_H
55