From fbe430fae98ea3b5dbba064bbf8709390d4ff8e5 Mon Sep 17 00:00:00 2001
From: Alyssa Rosenzweig <alyssa@collabora.com>
Date: Mon, 4 Jul 2022 16:43:59 -0400
Subject: [PATCH] panfrost: Move bifrost_lanes_per_warp to common

Whereas the compiler needs to know the warp size for lowering divergent
indirects, the driver needs to know it to report the subgroup size. Move the
Bifrost-specific helper to common and add the trivial implementation for
Midgard.

Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17265>
---
 src/panfrost/bifrost/bi_quirks.h       | 13 -------------
 src/panfrost/bifrost/bifrost_compile.c |  2 +-
 src/panfrost/util/pan_ir.h             | 18 ++++++++++++++++++
 3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/src/panfrost/bifrost/bi_quirks.h b/src/panfrost/bifrost/bi_quirks.h
index ec21da0d2ca..5dd75dd1db6 100644
--- a/src/panfrost/bifrost/bi_quirks.h
+++ b/src/panfrost/bifrost/bi_quirks.h
@@ -55,17 +55,4 @@ bifrost_get_quirks(unsigned product_id)
         }
 }
 
-/* How many lanes per architectural warp (subgroup)? Used to lower divergent
- * indirects. */
-
-static inline unsigned
-bifrost_lanes_per_warp(unsigned product_id)
-{
-        switch (product_id >> 12) {
-        case 6: return 4;
-        case 7: return 8;
-        default: return 16;
-        }
-}
-
 #endif
diff --git a/src/panfrost/bifrost/bifrost_compile.c b/src/panfrost/bifrost/bifrost_compile.c
index e6c97f3f369..431f4031959 100644
--- a/src/panfrost/bifrost/bifrost_compile.c
+++ b/src/panfrost/bifrost/bifrost_compile.c
@@ -4566,7 +4566,7 @@ bi_optimize_nir(nir_shader *nir, unsigned gpu_id, bool is_blend)
                 nir_convert_to_lcssa(nir, true, true);
                 NIR_PASS_V(nir, nir_divergence_analysis);
                 NIR_PASS_V(nir, bi_lower_divergent_indirects,
-                                bifrost_lanes_per_warp(gpu_id));
+                                pan_subgroup_size(gpu_id >> 12));
                 NIR_PASS_V(nir, nir_shader_instructions_pass,
                         nir_invalidate_divergence, nir_metadata_all, NULL);
         }
diff --git a/src/panfrost/util/pan_ir.h b/src/panfrost/util/pan_ir.h
index 5a910c7cdd4..820a6e61455 100644
--- a/src/panfrost/util/pan_ir.h
+++ b/src/panfrost/util/pan_ir.h
@@ -502,4 +502,22 @@ bool pan_nir_lower_64bit_intrin(nir_shader *shader);
 bool pan_lower_helper_invocation(nir_shader *shader);
 bool pan_lower_sample_pos(nir_shader *shader);
 
+/*
+ * Helper returning the subgroup size. Generally, this is equal to the number of
+ * threads in a warp. For Midgard (including warping models), this returns 1, as
+ * subgroups are not supported.
+ */
+static inline unsigned
+pan_subgroup_size(unsigned arch)
+{
+        if (arch >= 9)
+                return 16;
+        else if (arch >= 7)
+                return 8;
+        else if (arch >= 6)
+                return 4;
+        else
+                return 1;
+}
+
 #endif