On scalar ISAs, nir_lower_io_to_scalar_early enables significant optimizations. However, on vector ISAs, it is counterproductive and impedes optimal codegen. This patch only calls nir_lower_io_to_scalar_early for scalar ISAs. It appears that at present there are no upstreamed drivers using Gallium, NIR, and a vector ISA, so for existing code, this should be a no-op. However, this patch is necessary for the upcoming Panfrost (Midgard) and Lima (Utgard) compilers, which are vector.
With this patch, Panfrost is able to consume NIR directly, rather than TGSI with the TGSI->NIR conversion. For how this affects Lima, see https://www.mail-archive.com/mesa-dev@lists.freedesktop.org/msg189216.html Signed-off-by: Alyssa Rosenzweig <aly...@rosenzweig.io> --- src/mesa/state_tracker/st_glsl_to_nir.cpp | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/src/mesa/state_tracker/st_glsl_to_nir.cpp b/src/mesa/state_tracker/st_glsl_to_nir.cpp index 24776f7f9c..911284401e 100644 --- a/src/mesa/state_tracker/st_glsl_to_nir.cpp +++ b/src/mesa/state_tracker/st_glsl_to_nir.cpp @@ -665,7 +665,10 @@ st_link_nir(struct gl_context *ctx, mask = (nir_variable_mode)(mask | nir_var_shader_out); nir_shader *nir = shader->Program->nir; - NIR_PASS_V(nir, nir_lower_io_to_scalar_early, mask); + + if (is_scalar[i]) + NIR_PASS_V(nir, nir_lower_io_to_scalar_early, mask); + st_nir_opts(nir, is_scalar[i]); } -- 2.19.1 _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
