[libc-commits] [libc] [libc] Change the GPU to use builtin memory functions (PR #68003)
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libc-commits at lists.llvm.org
Mon Oct 2 09:21:31 PDT 2023
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-libc
<details>
<summary>Changes</summary>
Summary:
The GPU build is special in the sense that we always know that
up-to-date `clang` is always going to be the compiler. This allows us to
rely directly on builtins, which allow us to push a lot of this
complexity into the backend. Backend implementations are favored on
the GPU because it allows us to do a lot more target specific
optimizations. This patch changes over the common memory functions to
use builtin versions when building for AMDGPU or NVPTX.
---
Full diff: https://github.com/llvm/llvm-project/pull/68003.diff
5 Files Affected:
- (added) libc/src/string/memory_utils/generic/builtin.h (+57)
- (modified) libc/src/string/memory_utils/inline_bcmp.h (+4-1)
- (modified) libc/src/string/memory_utils/inline_memcpy.h (+4-1)
- (modified) libc/src/string/memory_utils/inline_memmove.h (+4-1)
- (modified) libc/src/string/memory_utils/inline_memset.h (+4-1)
``````````diff
diff --git a/libc/src/string/memory_utils/generic/builtin.h b/libc/src/string/memory_utils/generic/builtin.h
new file mode 100644
index 000000000000000..cfbd7e3ef361434
--- /dev/null
+++ b/libc/src/string/memory_utils/generic/builtin.h
@@ -0,0 +1,57 @@
+//===-- Trivial builtin implementations ----------------------------------===//
+//
+// 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_STRING_MEMORY_UTILS_GENERIC_BUILTIN_H
+#define LLVM_LIBC_SRC_STRING_MEMORY_UTILS_GENERIC_BUILTIN_H
+
+#include "src/__support/macros/config.h" // LIBC_INLINE
+#include "src/__support/macros/optimization.h" // LIBC_LOOP_NOUNROLL
+#include "src/string/memory_utils/utils.h" // Ptr, CPtr
+
+#include <stddef.h> // size_t
+
+namespace LIBC_NAMESPACE {
+
+static_assert(LIBC_HAS_BUILTIN(__builtin_memcpy), "Builtin not defined");
+static_assert(LIBC_HAS_BUILTIN(__builtin_memset), "Builtin not defined");
+static_assert(LIBC_HAS_BUILTIN(__builtin_memmove), "Builtin not defined");
+static_assert(LIBC_HAS_BUILTIN(__builtin_bcmp), "Builtin not defined");
+
+[[maybe_unused]] LIBC_INLINE void
+inline_memcpy_builtin(Ptr dst, CPtr src, size_t count, size_t offset = 0) {
+ __builtin_memcpy(dst + offset, src + offset, count);
+}
+
+[[maybe_unused]] LIBC_INLINE void inline_memmove_builtin(Ptr dst, CPtr src,
+ size_t count) {
+ __builtin_memmove(dst, src, count);
+}
+
+[[maybe_unused]] LIBC_INLINE static void
+inline_memset_builtin(Ptr dst, uint8_t value, size_t count, size_t offset = 0) {
+ __builtin_memset(dst + offset, value, count);
+}
+
+[[maybe_unused]] LIBC_INLINE BcmpReturnType
+inline_bcmp_builtin(CPtr p1, CPtr p2, size_t count, size_t offset = 0) {
+ return __builtin_bcmp(p1 + offset, p2 + offset, count)
+ ? BcmpReturnType::NONZERO()
+ : BcmpReturnType::ZERO();
+}
+
+[[maybe_unused]] LIBC_INLINE MemcmpReturnType
+inline_memcmp_builtin(CPtr p1, CPtr p2, size_t count, size_t offset = 0) {
+ int32_t diff = __builtin_memcmp(p1 + offset, p2 + offset, count);
+ if (diff)
+ return diff;
+ return MemcmpReturnType::ZERO();
+}
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STRING_MEMORY_UTILS_GENERIC_BUILTIN_H
diff --git a/libc/src/string/memory_utils/inline_bcmp.h b/libc/src/string/memory_utils/inline_bcmp.h
index b1c981d859e0223..1901f61e2daaeeb 100644
--- a/libc/src/string/memory_utils/inline_bcmp.h
+++ b/libc/src/string/memory_utils/inline_bcmp.h
@@ -23,9 +23,12 @@
#elif defined(LIBC_TARGET_ARCH_IS_ANY_RISCV)
#include "src/string/memory_utils/riscv/inline_bcmp.h"
#define LIBC_SRC_STRING_MEMORY_UTILS_BCMP inline_bcmp_riscv
-#elif defined(LIBC_TARGET_ARCH_IS_ARM) || defined(LIBC_TARGET_ARCH_IS_GPU)
+#elif defined(LIBC_TARGET_ARCH_IS_ARM)
#include "src/string/memory_utils/generic/byte_per_byte.h"
#define LIBC_SRC_STRING_MEMORY_UTILS_BCMP inline_bcmp_byte_per_byte
+#elif defined(LIBC_TARGET_ARCH_IS_GPU)
+#include "src/string/memory_utils/generic/builtin.h"
+#define LIBC_SRC_STRING_MEMORY_UTILS_BCMP inline_bcmp_builtin
#else
#error "Unsupported architecture"
#endif
diff --git a/libc/src/string/memory_utils/inline_memcpy.h b/libc/src/string/memory_utils/inline_memcpy.h
index 0b8a7848da87b4a..a92bf4ddf881d54 100644
--- a/libc/src/string/memory_utils/inline_memcpy.h
+++ b/libc/src/string/memory_utils/inline_memcpy.h
@@ -28,9 +28,12 @@
#elif defined(LIBC_TARGET_ARCH_IS_ANY_RISCV)
#include "src/string/memory_utils/riscv/inline_memcpy.h"
#define LIBC_SRC_STRING_MEMORY_UTILS_MEMCPY inline_memcpy_riscv
-#elif defined(LIBC_TARGET_ARCH_IS_ARM) || defined(LIBC_TARGET_ARCH_IS_GPU)
+#elif defined(LIBC_TARGET_ARCH_IS_ARM)
#include "src/string/memory_utils/generic/byte_per_byte.h"
#define LIBC_SRC_STRING_MEMORY_UTILS_MEMCPY inline_memcpy_byte_per_byte
+#elif defined(LIBC_TARGET_ARCH_IS_GPU)
+#include "src/string/memory_utils/generic/builtin.h"
+#define LIBC_SRC_STRING_MEMORY_UTILS_MEMCPY inline_memcpy_builtin
#else
#error "Unsupported architecture"
#endif
diff --git a/libc/src/string/memory_utils/inline_memmove.h b/libc/src/string/memory_utils/inline_memmove.h
index 0d31e10eaff28ed..f72ea24ab538d69 100644
--- a/libc/src/string/memory_utils/inline_memmove.h
+++ b/libc/src/string/memory_utils/inline_memmove.h
@@ -20,9 +20,12 @@
#elif defined(LIBC_TARGET_ARCH_IS_ANY_RISCV)
#include "src/string/memory_utils/riscv/inline_memmove.h"
#define LIBC_SRC_STRING_MEMORY_UTILS_MEMMOVE inline_memmove_riscv
-#elif defined(LIBC_TARGET_ARCH_IS_ARM) || defined(LIBC_TARGET_ARCH_IS_GPU)
+#elif defined(LIBC_TARGET_ARCH_IS_ARM)
#include "src/string/memory_utils/generic/byte_per_byte.h"
#define LIBC_SRC_STRING_MEMORY_UTILS_MEMMOVE inline_memmove_byte_per_byte
+#elif defined(LIBC_TARGET_ARCH_IS_GPU)
+#include "src/string/memory_utils/generic/builtin.h"
+#define LIBC_SRC_STRING_MEMORY_UTILS_MEMMOVE inline_memmove_builtin
#else
#error "Unsupported architecture"
#endif
diff --git a/libc/src/string/memory_utils/inline_memset.h b/libc/src/string/memory_utils/inline_memset.h
index f20ae45fa753b44..1c07c1ca4bffc0e 100644
--- a/libc/src/string/memory_utils/inline_memset.h
+++ b/libc/src/string/memory_utils/inline_memset.h
@@ -24,9 +24,12 @@
#elif defined(LIBC_TARGET_ARCH_IS_ANY_RISCV)
#include "src/string/memory_utils/riscv/inline_memset.h"
#define LIBC_SRC_STRING_MEMORY_UTILS_MEMSET inline_memset_riscv
-#elif defined(LIBC_TARGET_ARCH_IS_ARM) || defined(LIBC_TARGET_ARCH_IS_GPU)
+#elif defined(LIBC_TARGET_ARCH_IS_ARM)
#include "src/string/memory_utils/generic/byte_per_byte.h"
#define LIBC_SRC_STRING_MEMORY_UTILS_MEMSET inline_memset_byte_per_byte
+#elif defined(LIBC_TARGET_ARCH_IS_GPU)
+#include "src/string/memory_utils/generic/builtin.h"
+#define LIBC_SRC_STRING_MEMORY_UTILS_MEMSET inline_memset_builtin
#else
#error "Unsupported architecture"
#endif
``````````
</details>
https://github.com/llvm/llvm-project/pull/68003
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