[Mesa-dev] [PATCH] radeonsi: don't use allocas for arrays with LLVM 3.8

[Marek Olšák]

FYI, I've already committed this because our other team needs this bug fix.

Marek

On Thu, Aug 25, 2016 at 8:26 PM, Marek Olšák <maraeo at gmail.com> wrote:
> From: Marek Olšák <marek.olsak at amd.com>
>
> It crashes.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97413
> ---
>  src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c b/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
> index 71f52fd..4643e6d 100644
> --- a/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
> +++ b/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
> @@ -552,22 +552,24 @@ static void emit_declaration(struct lp_build_tgsi_context *bld_base,
>                          *
>                          * Note that 16 is the number of vector elements that
>                          * LLVM will store in a register, so theoretically an
>                          * array with up to 4 * 16 = 64 elements could be
>                          * handled this way, but whether that's a good idea
>                          * depends on VGPR register pressure elsewhere.
>                          *
>                          * FIXME: We shouldn't need to have the non-alloca
>                          * code path for arrays. LLVM should be smart enough to
>                          * promote allocas into registers when profitable.
> +                        *
> +                        * LLVM 3.8 crashes with this.
>                          */
> -                       if (array_size > 16) {
> +                       if (HAVE_LLVM >= 0x0309 && array_size > 16) {
>                                 array_alloca = LLVMBuildAlloca(builder,
>                                         LLVMArrayType(bld_base->base.vec_type,
>                                                       array_size), "array");
>                                 ctx->temp_array_allocas[id] = array_alloca;
>                         }
>                 }
>
>                 if (!ctx->temps_count) {
>                         ctx->temps_count = bld_base->info->file_max[TGSI_FILE_TEMPORARY] + 1;
>                         ctx->temps = MALLOC(TGSI_NUM_CHANNELS * ctx->temps_count * sizeof(LLVMValueRef));
> --
> 2.7.4
>