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48 lines
1.3 KiB
48 lines
1.3 KiB
5 years ago
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From 8f5c033958e2f1868322657be31fa62d689e9ecc Mon Sep 17 00:00:00 2001
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From: Nicker <nickersk@gmail.com>
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Date: Tue, 31 Jul 2018 13:01:38 +0200
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Subject: [PATCH] log2 give up on gcc constant optimizations
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diff --git a/include/linux/log2.h b/include/linux/log2.h
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index fd7ff3d9..f38fae23 100644
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--- a/include/linux/log2.h
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+++ b/include/linux/log2.h
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@@ -15,12 +15,6 @@
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#include <linux/types.h>
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#include <linux/bitops.h>
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-/*
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- * deal with unrepresentable constant logarithms
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- */
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-extern __attribute__((const, noreturn))
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-int ____ilog2_NaN(void);
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-
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/*
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* non-constant log of base 2 calculators
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* - the arch may override these in asm/bitops.h if they can be implemented
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@@ -85,7 +79,7 @@ unsigned long __rounddown_pow_of_two(unsigned long n)
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#define ilog2(n) \
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( \
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__builtin_constant_p(n) ? ( \
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- (n) < 1 ? ____ilog2_NaN() : \
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+ (n) < 2 ? 0 : \
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(n) & (1ULL << 63) ? 63 : \
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(n) & (1ULL << 62) ? 62 : \
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(n) & (1ULL << 61) ? 61 : \
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@@ -148,10 +142,7 @@ unsigned long __rounddown_pow_of_two(unsigned long n)
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(n) & (1ULL << 4) ? 4 : \
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(n) & (1ULL << 3) ? 3 : \
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(n) & (1ULL << 2) ? 2 : \
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- (n) & (1ULL << 1) ? 1 : \
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- (n) & (1ULL << 0) ? 0 : \
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- ____ilog2_NaN() \
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- ) : \
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+ 1 ) : \
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(sizeof(n) <= 4) ? \
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__ilog2_u32(n) : \
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__ilog2_u64(n) \
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--
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2.17.1
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