Re: [Qemu-devel] [PATCH] tcg: fix 16-byte vector operations detection

[Miroslav Rezanina]

On Wed, Mar 28, 2018 at 03:31:52PM +0200, Laurent Vivier wrote:
> configure tries to detect if the compiler
> supports 16-byte vector operations.
> 
> As stated in the comment of the detection
> program, there is a problem with the system
> compiler on GCC on Centos 7.
> 
> This program doesn't actually detect the problem
> with GCC on RHEL7 on PPC64LE (Red Hat 4.8.5-28).
> 
> This patch updates the test to look more like
> it is in QEMU helpers, and now detects the problem.
> 
> The error reported is:
> 
>   CC      ppc64-softmmu/accel/tcg/tcg-runtime-gvec.o
>   ..//accel/tcg/tcg-runtime-gvec.c: In function ‘helper_gvec_shl8i’:
>   ../accel/tcg/tcg-runtime-gvec.c:558:26: internal compiler error: in 
> emit_move_insn, at expr.c:3495
>            *(vec8 *)(d + i) = *(vec8 *)(a + i) << shift;
>                             ^
> Fixes: db43267 "tcg: Add generic vector expanders"
> Signed-off-by: Laurent Vivier <address@hidden>
> ---
>  configure | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/configure b/configure
> index 4d0e92c96c..a2301dd0dc 100755
> --- a/configure
> +++ b/configure
> @@ -5054,6 +5054,14 @@ static S2 c2;
>  static S4 c4;
>  static S8 c8;
>  static int i;
> +void helper(void *d, void *a, int shift, int i);
> +void helper(void *d, void *a, int shift, int i)
> +{
> +  *(U1 *)(d + i) = *(U1 *)(a + i) << shift;
> +  *(U2 *)(d + i) = *(U2 *)(a + i) << shift;
> +  *(U4 *)(d + i) = *(U4 *)(a + i) << shift;
> +  *(U8 *)(d + i) = *(U8 *)(a + i) << shift;
> +}
>  int main(void)
>  {
>    a1 += b1; a2 += b2; a4 += b4; a8 += b8;
> -- 
> 2.14.3
> 
>

Build works correctly for RHEL 7 with this patch

Reviewed-by: Miroslav Rezanina <address@hidden>