[clang] [llvm] [X86][AMX] Support AMX-FP8 (PR #113850)

[Phoebe Wang via cfe-commits]

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+/*===------------- amxfp8intrin.h - AMX intrinsics -*- 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 __IMMINTRIN_H
+#error "Never use <amxfp8intrin.h> directly; include <immintrin.h> instead."
+#endif /* __IMMINTRIN_H */
+
+#ifndef __AMXFP8INTRIN_H
+#define __AMXFP8INTRIN_H
+#ifdef __x86_64__
+
+/// These instructions compute dot product of brain-float8 (BF8) or
+/// hybrid-float8 (HF8) accumulating into a single precision (FP32). The input
+/// elements can be BF8 or HF8. These instructions have three tile operands, one
+/// source/dest accumulator operand, and two source operands, \a a and \a b. The
+/// \a a and \a b operands can be BF8 or HF8 independently, and the source/dest
+/// operand, \a dst is always FP32.
+///
+/// \headerfile <immintrin.h>
+///
+/// \code
+/// void _tile_dpbf8ps (__tile dst, __tile a, __tile b)
+/// \endcode
+///
+/// This intrinsic corresponds to the \c TDPBF8PS instruction, which is the dot
+/// product of a BF8 value (\a a) by a BF8 value (\a b) accumulating into a
+/// Single Precision (FP32) source/dest (\a dst).
+///
+/// \param dst
+///    The destination tile. Max size is 1024 Bytes.
+/// \param a
+///    The 1st source tile. Max size is 1024 Bytes.
+/// \param b
+///    The 2nd source tile. Max size is 1024 Bytes.
+#define _tile_dpbf8ps(dst, a, b) __builtin_ia32_tdpbf8ps((dst), (a), (b))
+
+/// \code
+/// void _tile_dpbhf8ps (__tile dst, __tile a, __tile b)
+/// \endcode
+///
+/// This intrinsic corresponds to the \c TDPBHF8PS instruction, which is the dot
+/// product of a BF8 value (\a a) by an HF8 value (\a b) accumulating into a
+/// Single Precision (FP32) source/dest (\a dst).
+///
+/// \param dst
+///    The destination tile. Max size is 1024 Bytes.
+/// \param a
+///    The 1st source tile. Max size is 1024 Bytes.
+/// \param b
+///    The 2nd source tile. Max size is 1024 Bytes.
----------------
phoebewang wrote:

The current rule of rule of thumb is
```
Intrinsic description

Pseudo code if any

/// \headerfile <immintrin.h>

/// \code
/// void _tile_dpbhf8ps (__tile dst, __tile a, __tile b)
/// \endcode

/// This intrinsic corresponds to the \c TDPBHF8PS instruction.

/// \param dst
///    The destination tile. Max size is 1024 Bytes.
/// \param a
///    The 1st source tile. Max size is 1024 Bytes.
/// \param b
///    The 2nd source tile. Max size is 1024 Bytes.
```
See examples in other files.

https://github.com/llvm/llvm-project/pull/113850