[llvm-dev] Is the correct behavior of getelementptr i192* for opt + llc -march=aarch64?

[Tom Stellard via llvm-dev]

On Wed, Nov 09, 2016 at 12:31:18PM +0900, MITSUNARI Shigeo via llvm-dev wrote:
> Hi all,
> opt and opt + llc generate the difference aarch64 asm code for the following LLVM code.
> 
> Is it intended behavior?
> I expected (A) because I cast %p from i192* to i64*.
> The information is dropped by opt and 8-byte padding is inserted or I write a bad code?
> 
> % cat a.ll
> define void @store0_to_p4(i192* %p)
> {
>   %p1 = bitcast i192* %p to i64*
>   %p2 = getelementptr i64, i64* %p1, i64 3
>   %p3 = getelementptr i64, i64* %p2, i64 1
>   store i64 0, i64* %p3
>   ret void
> }
> 
> % llc-3.8 a.ll -O3 -o - -march=aarch64
> store0_to_p4:
>   str     xzr, [x0, #32] ; (A)
>   ret
> 
> % opt-3.8 -O3 a.ll -o - | llc-3.8 -O3 -o - -march=aarch64

Is your default target aarch64?  Otherwise opt may be assuming a different
target which might explain the difference.

-Tom
> store0_to_p4:
>   str     xzr, [x0, #40] ; (B)
>   ret
> 
> Yours,
>  Shigeo
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