Re: [PATCH][AArch64] Fix PR79041

[Yvan Roux <yvan.roux@linaro.org>]

Hi

On 27 June 2017 at 16:49, Wilco Dijkstra <Wilco.Dijkstra@arm.com> wrote:
> As described in PR79041, -mcmodel=large -mpc-relative-literal-loads
> may be used to avoid generating ADRP/ADD or ADRP/LDR.  However both
> trunk and GCC7 may still emit ADRP for some constant pool literals.
> Fix this by adding a aarch64_pcrelative_literal_loads check.
>
> OK for trunk/GCC7 backport?

I can't approve it, but the patch is ok for me, I've built and
regtested the very same patch for aarch64-linux-gnu,
aarch64-none-elf and aarch64_be-none-elf targets :)

Yvan

> ChangeLog:
> 2017-06-27  Wilco Dijkstra  <wdijkstr@arm.com>
>
>         PR target/79041
>         * config/aarch64/aarch64.c (aarch64_classify_symbol):
>         Avoid SYMBOL_SMALL_ABSOLUTE .
>         * testsuite/gcc.target/aarch64/pr79041-2.c: New test.
> --
> diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
> index 060cd8476d2954119daac495ecb059c9be73edbe..329d244e9cf16dbdf849e5dd02b3999caf0cd5a7 100644
> --- a/gcc/config/aarch64/aarch64.c
> +++ b/gcc/config/aarch64/aarch64.c
> @@ -10042,7 +10042,7 @@ aarch64_classify_symbol (rtx x, rtx offset)
>           /* This is alright even in PIC code as the constant
>              pool reference is always PC relative and within
>              the same translation unit.  */
> -         if (CONSTANT_POOL_ADDRESS_P (x))
> +         if (CONSTANT_POOL_ADDRESS_P (x) && !aarch64_pcrelative_literal_loads)
>             return SYMBOL_SMALL_ABSOLUTE;
>           else
>             return SYMBOL_FORCE_TO_MEM;
> diff --git a/gcc/testsuite/gcc.target/aarch64/pr79041-2.c b/gcc/testsuite/gcc.target/aarch64/pr79041-2.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..e7899725bad2b770f8488a07f99792113275bdf2
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/pr79041-2.c
> @@ -0,0 +1,10 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -mcmodel=large -mpc-relative-literal-loads" } */
> +
> +__int128
> +t (void)
> +{
> +  return (__int128)1 << 80;
> +}
> +
> +/* { dg-final { scan-assembler "adr" } } */