Operator precedence issue in fma.c.

Operator precedence issue in fma.c.

[Jukka Jylänki]

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Hi,

building musl fma.c with Clang/LLVM 3.4, I get the following message:

fma.c:276:22: warning: ^ has lower precedence than !=; != will be evaluated
first [-Wparentheses]

                if (bits_lost != 1 ^ (int)(uhi.i & 1)) {

                    ~~~~~~~~~~~~~~~^

fma.c:276:22: note: place parentheses around the '!=' expression to silence
this warning

                if (bits_lost != 1 ^ (int)(uhi.i & 1)) {

                                   ^

                    (             )

fma.c:276:22: note: place parentheses around the ^ expression to evaluate
it first

                if (bits_lost != 1 ^ (int)(uhi.i & 1)) {

                                   ^

                                 (                   )

How does that look to you guys? Is that a real error?

Best Regards,
   Jukka

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Re: Operator precedence issue in fma.c.

[Rich Felker]

On Wed, Jan 28, 2015 at 04:33:53PM +0200, Jukka Jylänki wrote:
> Hi,
> 
> building musl fma.c with Clang/LLVM 3.4, I get the following message:
> 
> fma.c:276:22: warning: ^ has lower precedence than !=; != will be evaluated
> first [-Wparentheses]
> 
>                 if (bits_lost != 1 ^ (int)(uhi.i & 1)) {
> 
>                     ~~~~~~~~~~~~~~~^

I think the ^ operator here is being used as a logical xor rather than
a bitwise one and the code is working as intended, but since I didn't
write it I'll ask and see. If it is correct, I think removing the
spaces around the != and/or adding parens would make it clearer.

Rich