From bba607ac2b6fd14ce33bbff44fc1684e41541a7a Mon Sep 17 00:00:00 2001
From: Caio Oliveira <caio.oliveira@intel.com>
Date: Fri, 14 Mar 2025 11:09:00 -0700
Subject: [PATCH] spirv: Move Convert opcodes handling to its own function

Take the opportunity to add a comment about why the bit_size
comes from the NIR def and not the original type.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Rohan Garg <rohan.garg@intel.com>
Reviewed-by: Georg Lehmann <dadschoorse@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34105>
---
 src/compiler/spirv/vtn_alu.c | 81 +++++++++++++++++++++---------------
 1 file changed, 48 insertions(+), 33 deletions(-)

diff --git a/src/compiler/spirv/vtn_alu.c b/src/compiler/spirv/vtn_alu.c
index caa2ad9a1ac..e3c10f51dc4 100644
--- a/src/compiler/spirv/vtn_alu.c
+++ b/src/compiler/spirv/vtn_alu.c
@@ -660,6 +660,52 @@ vtn_handle_deriv(struct vtn_builder *b, SpvOp opcode, nir_def *src)
    }
 }
 
+static nir_def *
+vtn_handle_convert(struct vtn_builder *b, SpvOp opcode,
+                   struct vtn_value *dest_val,
+                   const struct glsl_type *glsl_dest_type,
+                   nir_def *src)
+{
+   /* Use bit_size from NIR source instead of from the original src type,
+    * to account for mediump_16bit.  See vtn_handle_alu() for details.
+    */
+   unsigned src_bit_size = src->bit_size;
+   unsigned dst_bit_size = glsl_get_bit_size(glsl_dest_type);
+   nir_alu_type src_type = vtn_convert_op_src_type(opcode) | src_bit_size;
+   nir_alu_type dst_type = vtn_convert_op_dst_type(opcode) | dst_bit_size;
+
+   struct conversion_opts opts = {
+      .rounding_mode = nir_rounding_mode_undef,
+      .saturate = false,
+   };
+   vtn_foreach_decoration(b, dest_val, handle_conversion_opts, &opts);
+
+   if (opcode == SpvOpSatConvertSToU || opcode == SpvOpSatConvertUToS)
+      opts.saturate = true;
+
+   nir_def *result;
+
+   if (b->shader->info.stage == MESA_SHADER_KERNEL) {
+      if (opts.rounding_mode == nir_rounding_mode_undef && !opts.saturate) {
+         result = nir_type_convert(&b->nb, src, src_type, dst_type,
+                                   nir_rounding_mode_undef);
+      } else {
+         result = nir_convert_alu_types(&b->nb, dst_bit_size, src,
+                                        src_type, dst_type,
+                                        opts.rounding_mode, opts.saturate);
+      }
+   } else {
+      vtn_fail_if(opts.rounding_mode != nir_rounding_mode_undef &&
+                  dst_type != nir_type_float16,
+                  "Rounding modes are only allowed on conversions to "
+                  "16-bit float types");
+      result = nir_type_convert(&b->nb, src, src_type, dst_type,
+                                opts.rounding_mode);
+   }
+
+   return result;
+}
+
 void
 vtn_handle_alu(struct vtn_builder *b, SpvOp opcode,
                const uint32_t *w, unsigned count)
@@ -911,40 +957,9 @@ vtn_handle_alu(struct vtn_builder *b, SpvOp opcode,
    case SpvOpSConvert:
    case SpvOpFConvert:
    case SpvOpSatConvertSToU:
-   case SpvOpSatConvertUToS: {
-      unsigned src_bit_size = src[0]->bit_size;
-      unsigned dst_bit_size = glsl_get_bit_size(dest_type);
-      nir_alu_type src_type = vtn_convert_op_src_type(opcode) | src_bit_size;
-      nir_alu_type dst_type = vtn_convert_op_dst_type(opcode) | dst_bit_size;
-
-      struct conversion_opts opts = {
-         .rounding_mode = nir_rounding_mode_undef,
-         .saturate = false,
-      };
-      vtn_foreach_decoration(b, dest_val, handle_conversion_opts, &opts);
-
-      if (opcode == SpvOpSatConvertSToU || opcode == SpvOpSatConvertUToS)
-         opts.saturate = true;
-
-      if (b->shader->info.stage == MESA_SHADER_KERNEL) {
-         if (opts.rounding_mode == nir_rounding_mode_undef && !opts.saturate) {
-            dest->def = nir_type_convert(&b->nb, src[0], src_type, dst_type,
-                                         nir_rounding_mode_undef);
-         } else {
-            dest->def = nir_convert_alu_types(&b->nb, dst_bit_size, src[0],
-                                              src_type, dst_type,
-                                              opts.rounding_mode, opts.saturate);
-         }
-      } else {
-         vtn_fail_if(opts.rounding_mode != nir_rounding_mode_undef &&
-                     dst_type != nir_type_float16,
-                     "Rounding modes are only allowed on conversions to "
-                     "16-bit float types");
-         dest->def = nir_type_convert(&b->nb, src[0], src_type, dst_type,
-                                      opts.rounding_mode);
-      }
+   case SpvOpSatConvertUToS:
+      dest->def = vtn_handle_convert(b, opcode, dest_val, dest_type, src[0]);
       break;
-   }
 
    case SpvOpBitFieldInsert:
    case SpvOpBitFieldSExtract: