From 437a0a54eea7b101e8a5b70688009956f6522ed0 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 20 Jun 2008 21:50:20 +0200 Subject: [PATCH] x86, bitops: make constant-bit set/clear_bit ops faster, gcc workaround Jeremy Fitzhardinge reported this compiler bug: Suggestion from Linus: add "r" to the input constraint of the set_bit()/clear_bit()'s constant 'nr' branch: Blows up on "gcc version 3.4.4 20050314 (prerelease) (Debian 3.4.3-13)": CC init/main.o include2/asm/bitops.h: In function `start_kernel': include2/asm/bitops.h:59: warning: asm operand 1 probably doesn't match constraints include2/asm/bitops.h:59: warning: asm operand 1 probably doesn't match constraints include2/asm/bitops.h:59: warning: asm operand 1 probably doesn't match constraints include2/asm/bitops.h:59: error: impossible constraint in `asm' include2/asm/bitops.h:59: error: impossible constraint in `asm' include2/asm/bitops.h:59: error: impossible constraint in `asm' Reported-by: Jeremy Fitzhardinge Signed-off-by: Ingo Molnar --- include/asm-x86/bitops.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/asm-x86/bitops.h b/include/asm-x86/bitops.h index 6c50548197..96b1829cea 100644 --- a/include/asm-x86/bitops.h +++ b/include/asm-x86/bitops.h @@ -58,7 +58,7 @@ static inline void set_bit(unsigned int nr, volatile unsigned long *addr) if (IS_IMMEDIATE(nr)) { asm volatile(LOCK_PREFIX "orb %1,%0" : CONST_MASK_ADDR(nr, addr) - : "i" (CONST_MASK(nr)) + : "iq" ((u8)CONST_MASK(nr)) : "memory"); } else { asm volatile(LOCK_PREFIX "bts %1,%0" @@ -95,7 +95,7 @@ static inline void clear_bit(int nr, volatile unsigned long *addr) if (IS_IMMEDIATE(nr)) { asm volatile(LOCK_PREFIX "andb %1,%0" : CONST_MASK_ADDR(nr, addr) - : "i" (~CONST_MASK(nr))); + : "iq" ((u8)~CONST_MASK(nr))); } else { asm volatile(LOCK_PREFIX "btr %1,%0" : BITOP_ADDR(addr) -- 2.39.5