The generated asm for logical-ops.c test case looks as follows on x86-64: GCC 4.6: 0000000000000000 <and_bool>: 0: 31 c0 xor %eax,%eax 2: 85 f6 test %esi,%esi 4: 0f 95 c0 setne %al 7: 31 d2 xor %edx,%edx 9: 85 ff test %edi,%edi b: 0f 95 c2 setne %dl e: 21 d0 and %edx,%eax 10: c3 retq 0000000000000020 <uand_bool>: 20: 31 c0 xor %eax,%eax 22: 85 f6 test %esi,%esi 24: 0f 95 c0 setne %al 27: 31 d2 xor %edx,%edx 29: 85 ff test %edi,%edi 2b: 0f 95 c2 setne %dl 2e: 21 d0 and %edx,%eax 30: c3 retq 0000000000000040 <or_bool>: 40: 09 fe or %edi,%esi 42: 0f 95 c0 setne %al 45: 0f b6 c0 movzbl %al,%eax 48: c3 retq 0000000000000050 <uor_bool>: 50: 09 fe or %edi,%esi 52: 0f 95 c0 setne %al 55: 0f b6 c0 movzbl %al,%eax 58: c3 retq Sparse/LLVM: 0000000000000000 <and_bool>: 0: 85 f6 test %esi,%esi 2: 0f 95 c0 setne %al 5: 85 ff test %edi,%edi 7: 0f 95 c1 setne %cl a: 20 c1 and %al,%cl c: 0f b6 c1 movzbl %cl,%eax f: c3 retq 0000000000000010 <uand_bool>: 10: 85 f6 test %esi,%esi 12: 0f 95 c0 setne %al 15: 85 ff test %edi,%edi 17: 0f 95 c1 setne %cl 1a: 20 c1 and %al,%cl 1c: 0f b6 c1 movzbl %cl,%eax 1f: c3 retq 0000000000000020 <or_bool>: 20: 09 f7 or %esi,%edi 22: 0f 95 c0 setne %al 25: 0f b6 c0 movzbl %al,%eax 28: c3 retq 0000000000000030 <uor_bool>: 30: 09 f7 or %esi,%edi 32: 0f 95 c0 setne %al 35: 0f b6 c0 movzbl %al,%eax 38: c3 retq Cc: Christopher Li <sparse@chrisli.org> Cc: Jeff Garzik <jgarzik@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Pekka Enberg <penberg@kernel.org>