From 6388896985da7495ad0968322491953894d29637 Mon Sep 17 00:00:00 2001
From: Faith Ekstrand <faith.ekstrand@collabora.com>
Date: Wed, 1 Nov 2023 15:38:35 -0500
Subject: [PATCH] nir: add deref follower builder for casts.

This fixes intel_clc builds with llvm 17 on gfx125_bvh_build_DFS_DFS
where it dies in the lower indirect derefs pass.

Co-authored-by: Dave Airlie <airlied@redhat.com>
Fixes: 4a4e1757381c ("nir: Support deref instructions in lower_var_copies")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25536>
---
 src/compiler/nir/nir_builder.h | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/src/compiler/nir/nir_builder.h b/src/compiler/nir/nir_builder.h
index c9f3465406c..d2b5702d3c9 100644
--- a/src/compiler/nir/nir_builder.h
+++ b/src/compiler/nir/nir_builder.h
@@ -1483,9 +1483,12 @@ nir_build_deref_struct(nir_builder *build, nir_deref_instr *parent,
 }
 
 static inline nir_deref_instr *
-nir_build_deref_cast(nir_builder *build, nir_def *parent,
-                     nir_variable_mode modes, const struct glsl_type *type,
-                     unsigned ptr_stride)
+nir_build_deref_cast_with_alignment(nir_builder *build, nir_def *parent,
+                                    nir_variable_mode modes,
+                                    const struct glsl_type *type,
+                                    unsigned ptr_stride,
+                                    unsigned align_mul,
+                                    unsigned align_offset)
 {
    nir_deref_instr *deref =
       nir_deref_instr_create(build->shader, nir_deref_type_cast);
@@ -1493,6 +1496,8 @@ nir_build_deref_cast(nir_builder *build, nir_def *parent,
    deref->modes = modes;
    deref->type = type;
    deref->parent = nir_src_for_ssa(parent);
+   deref->cast.align_mul = align_mul;
+   deref->cast.align_offset = align_offset;
    deref->cast.ptr_stride = ptr_stride;
 
    nir_def_init(&deref->instr, &deref->def, parent->num_components,
@@ -1503,6 +1508,15 @@ nir_build_deref_cast(nir_builder *build, nir_def *parent,
    return deref;
 }
 
+static inline nir_deref_instr *
+nir_build_deref_cast(nir_builder *build, nir_def *parent,
+                     nir_variable_mode modes, const struct glsl_type *type,
+                     unsigned ptr_stride)
+{
+   return nir_build_deref_cast_with_alignment(build, parent, modes, type,
+                                              ptr_stride, 0, 0);
+}
+
 static inline nir_deref_instr *
 nir_alignment_deref_cast(nir_builder *build, nir_deref_instr *parent,
                          uint32_t align_mul, uint32_t align_offset)
@@ -1570,6 +1584,13 @@ nir_build_deref_follower(nir_builder *b, nir_deref_instr *parent,
 
       return nir_build_deref_struct(b, parent, leader->strct.index);
 
+   case nir_deref_type_cast:
+      return nir_build_deref_cast_with_alignment(b, &parent->def,
+                                                 leader->modes,
+                                                 leader->type,
+                                                 leader->cast.ptr_stride,
+                                                 leader->cast.align_mul,
+                                                 leader->cast.align_offset);
    default:
       unreachable("Invalid deref instruction type");
    }
-- 
2.41.0