From: Simon Marchi <simon.marchi@polymtl.ca>
To: Luis Machado <luis.machado@linaro.org>,
"gdb-patches@sourceware.org" <gdb-patches@sourceware.org>
Subject: Re: -Wtautological-bitwise-compare error in arm-tdep.c
Date: Fri, 15 May 2020 16:57:38 -0400 [thread overview]
Message-ID: <6d973400-466a-3127-783d-025bb5b7944a@polymtl.ca> (raw)
In-Reply-To: <09dc3a76-bc35-0079-c72b-1b0ae5845faf@linaro.org>
On 2020-05-15 4:41 p.m., Luis Machado wrote:
> On 5/15/20 5:32 PM, Simon Marchi via Gdb-patches wrote:
>> We get this error in arm-tdep.c when building with clang 11:
>>
>> CXX arm-tdep.o
>> /home/smarchi/src/binutils-gdb/gdb/arm-tdep.c:934:29: error: bitwise comparison always evaluates to false [-Werror,-Wtautological-bitwise-compare]
>> else if ((insn & 0xffb0) == 0xe950 /* ldrd Rt, Rt2,
>> ~~~~~~~~~~~~~~~~^~~~~~~~~
>>
>> Indeed, this can never evaluate to true. I tried to look at what the condition
>> should be, but it's a bit too deep into ARM instruction encoding for me. I am
>> pretty sure that the corresponding section in the ARM Architecture Reference
>> Manual [1] is F3.1.15, if somebody wants to take a stab at it.
>>
>> Simon
>>
>> [1] https://static.docs.arm.com/ddi0487/fb/DDI0487F_b_armv8_arm.pdf
>>
>
> Thanks for reporting this. I'll look into it. It may be a typo of some kind.
Yes, I suppose, it's just not a trivial typo to fix!
Simon
next prev parent reply other threads:[~2020-05-15 20:57 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-15 20:32 Simon Marchi
2020-05-15 20:41 ` Luis Machado
2020-05-15 20:57 ` Simon Marchi [this message]
2020-05-25 13:08 ` Luis Machado
2020-05-25 13:49 ` Simon Marchi
2020-05-25 13:51 ` Luis Machado
2020-05-26 9:45 ` Alan Hayward
2020-05-26 12:17 ` Luis Machado
2020-05-26 16:10 ` Alan Hayward
2020-05-27 12:43 ` Luis Machado
2020-05-27 14:00 ` Simon Marchi
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