[llvm-dev] Problem with Aarch64 ?

[Somenath Chakraborty via llvm-dev]

You are right!  Now the generated code is -

  %3 = sext i8 %2 to i64


On Wed, Sep 7, 2016 at 11:13 PM, Mehdi Amini <mehdi.amini at apple.com> wrote:

>
> On Sep 7, 2016, at 10:32 AM, Somenath Chakraborty via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
> Hello,
>
> I am facing an issue with a small test where there is a chance that
> sign-extension is not introduced as expected -
>
> #include <stdio.h>
>
> void func( long x )
> {
>     printf(" %ld \n", x);
> }
>
> int main()
> {
>     char c = -1;
>
>
> I believe the signedness of char is implementation defined, have you tried
> using `signed char`?
>
> —
> Mehdi
>
>
>     func ( c );  // c is zero extended to x
>     return 0;
> }
>
> generated IR -
>
> define i32 @main() #0 {
>  ........
>   store i8 -1, i8* %c, align 1
>   %2 = load i8, i8* %c, align 1
> *  %3 = zext i8 %2 to i64*
>   call void @func(i64 %3)
> }
>
> The value to the formal argument is zero-extended, different from x86_64.
> Is this a known issue ? Am I missing anything ?
>
> Thanks,
> Somenath
>
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>
>
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