Mesa (master): radeonsi: don' t use the real barrier instruction in tess ctrl shaders

[Marek Olšák]

Module: Mesa
Branch: master
Commit: baa0b3f4ccd960bb6131ba16b1f9d8736c6432c1
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=baa0b3f4ccd960bb6131ba16b1f9d8736c6432c1

Author: Marek Olšák <marek.olsak at amd.com>
Date:   Thu Apr  7 00:49:32 2016 +0200

radeonsi: don't use the real barrier instruction in tess ctrl shaders

Reviewed-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle at amd.com>

---

 src/gallium/drivers/radeonsi/si_shader.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index bf3f008..08da3e3 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -4282,6 +4282,14 @@ static void si_llvm_emit_barrier(const struct lp_build_tgsi_action *action,
 	struct si_shader_context *ctx = si_shader_context(bld_base);
 	struct gallivm_state *gallivm = bld_base->base.gallivm;
 
+	/* The real barrier instruction isn’t needed, because an entire patch
+	 * always fits into a single wave.
+	 */
+	if (ctx->type == TGSI_PROCESSOR_TESS_CTRL) {
+		emit_optimization_barrier(ctx);
+		return;
+	}
+
 	lp_build_intrinsic(gallivm->builder,
 			   HAVE_LLVM >= 0x0309 ? "llvm.amdgcn.s.barrier"
 					       : "llvm.AMDGPU.barrier.local",