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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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C
12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879/* SPDX-License-Identifier: GPL-2.0 */
/* * Copyright (C) 2023 Google LLC. */
#ifndef __UNROLL_H#define __UNROLL_H
#include <linux/args.h>
#ifdef CONFIG_CC_IS_CLANG#define __pick_unrolled(x, y) _Pragma(#x)#else#define __pick_unrolled(x, y) _Pragma(#y)#endif
/** * unrolled - loop attributes to ask the compiler to unroll it * * Usage: * * #define BATCH 8 * * unrolled_count(BATCH) * for (u32 i = 0; i < BATCH; i++) * // loop body without cross-iteration dependencies * * This is only a hint and the compiler is free to disable unrolling if it * thinks the count is suboptimal and may hurt performance and/or hugely * increase object code size. * Not having any cross-iteration dependencies (i.e. when iter x + 1 depends * on what iter x will do with variables) is not a strict requirement, but * provides best performance and object code size. * Available only on Clang and GCC 8.x onwards. */
/* Ask the compiler to pick an optimal unroll count, Clang only */#define unrolled \ __pick_unrolled(clang loop unroll(enable), /* nothing */)
/* Unroll each @n iterations of the loop */#define unrolled_count(n) \ __pick_unrolled(clang loop unroll_count(n), GCC unroll n)
/* Unroll the whole loop */#define unrolled_full \ __pick_unrolled(clang loop unroll(full), GCC unroll 65534)
/* Never unroll the loop */#define unrolled_none \ __pick_unrolled(clang loop unroll(disable), GCC unroll 1)
#define UNROLL(N, MACRO, args...) CONCATENATE(__UNROLL_, N)(MACRO, args)
#define __UNROLL_0(MACRO, args...)#define __UNROLL_1(MACRO, args...) __UNROLL_0(MACRO, args) MACRO(0, args)#define __UNROLL_2(MACRO, args...) __UNROLL_1(MACRO, args) MACRO(1, args)#define __UNROLL_3(MACRO, args...) __UNROLL_2(MACRO, args) MACRO(2, args)#define __UNROLL_4(MACRO, args...) __UNROLL_3(MACRO, args) MACRO(3, args)#define __UNROLL_5(MACRO, args...) __UNROLL_4(MACRO, args) MACRO(4, args)#define __UNROLL_6(MACRO, args...) __UNROLL_5(MACRO, args) MACRO(5, args)#define __UNROLL_7(MACRO, args...) __UNROLL_6(MACRO, args) MACRO(6, args)#define __UNROLL_8(MACRO, args...) __UNROLL_7(MACRO, args) MACRO(7, args)#define __UNROLL_9(MACRO, args...) __UNROLL_8(MACRO, args) MACRO(8, args)#define __UNROLL_10(MACRO, args...) __UNROLL_9(MACRO, args) MACRO(9, args)#define __UNROLL_11(MACRO, args...) __UNROLL_10(MACRO, args) MACRO(10, args)#define __UNROLL_12(MACRO, args...) __UNROLL_11(MACRO, args) MACRO(11, args)#define __UNROLL_13(MACRO, args...) __UNROLL_12(MACRO, args) MACRO(12, args)#define __UNROLL_14(MACRO, args...) __UNROLL_13(MACRO, args) MACRO(13, args)#define __UNROLL_15(MACRO, args...) __UNROLL_14(MACRO, args) MACRO(14, args)#define __UNROLL_16(MACRO, args...) __UNROLL_15(MACRO, args) MACRO(15, args)#define __UNROLL_17(MACRO, args...) __UNROLL_16(MACRO, args) MACRO(16, args)#define __UNROLL_18(MACRO, args...) __UNROLL_17(MACRO, args) MACRO(17, args)#define __UNROLL_19(MACRO, args...) __UNROLL_18(MACRO, args) MACRO(18, args)#define __UNROLL_20(MACRO, args...) __UNROLL_19(MACRO, args) MACRO(19, args)
#endif /* __UNROLL_H */