From: Luis Machado <luis.machado@linaro.org>
To: Simon Marchi <simon.marchi@polymtl.ca>,
"gdb-patches@sourceware.org" <gdb-patches@sourceware.org>
Subject: Re: -Wtautological-bitwise-compare error in arm-tdep.c
Date: Fri, 15 May 2020 17:41:02 -0300 [thread overview]
Message-ID: <09dc3a76-bc35-0079-c72b-1b0ae5845faf@linaro.org> (raw)
In-Reply-To: <fa18d42b-0365-762a-76af-589223cc05d2@polymtl.ca>
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.
next prev parent reply other threads:[~2020-05-15 20:41 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 [this message]
2020-05-15 20:57 ` Simon Marchi
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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