[Mesa-dev] [PATCH 2/2] spirv: fix bug when OpSpecConstantOp calls a conversion

[Samuel Iglesias Gonsálvez]

In that case, nir_eval_const_opcode() will evaluate the conversion
but as it was using destination's bit_size, the resulting
value was just a cast of the source constant value. By passing the
source's bit size, it does the conversion properly.

Fixes:

dEQP-VK.spirv_assembly.instruction.*.opspecconstantop.*convert*

Signed-off-by: Samuel Iglesias Gonsálvez <siglesias at igalia.com>
---
 src/compiler/spirv/spirv_to_nir.c | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/src/compiler/spirv/spirv_to_nir.c b/src/compiler/spirv/spirv_to_nir.c
index 2cc3c275ea9..ffbda4f1946 100644
--- a/src/compiler/spirv/spirv_to_nir.c
+++ b/src/compiler/spirv/spirv_to_nir.c
@@ -1348,14 +1348,35 @@ vtn_handle_constant(struct vtn_builder *b, SpvOp opcode,
          bool swap;
          nir_alu_type dst_alu_type = nir_get_nir_type_for_glsl_type(val->const_type);
          nir_alu_type src_alu_type = dst_alu_type;
-         nir_op op = vtn_nir_alu_op_for_spirv_opcode(opcode, &swap, src_alu_type, dst_alu_type);
-
          unsigned num_components = glsl_get_vector_elements(val->const_type);
-         unsigned bit_size =
-            glsl_get_bit_size(val->const_type);
+         unsigned bit_size;
 
-         nir_const_value src[4];
          assert(count <= 7);
+
+         switch (opcode) {
+         case SpvOpUConvert:
+         case SpvOpConvertFToU:
+         case SpvOpConvertFToS:
+         case SpvOpConvertSToF:
+         case SpvOpConvertUToF:
+         case SpvOpSConvert:
+         case SpvOpFConvert:
+            /* We have a source in a conversion */
+            src_alu_type =
+               nir_get_nir_type_for_glsl_type(
+                  vtn_value(b, w[4], vtn_value_type_constant)->const_type);
+            /* We use the bitsize of the conversion source to evaluate the opcode later */
+            bit_size = glsl_get_bit_size(
+               vtn_value(b, w[4], vtn_value_type_constant)->const_type);
+            break;
+         default:
+            bit_size = glsl_get_bit_size(val->const_type);
+         };
+
+
+         nir_op op = vtn_nir_alu_op_for_spirv_opcode(opcode, &swap, src_alu_type, dst_alu_type);
+         nir_const_value src[4];
+
          for (unsigned i = 0; i < count - 4; i++) {
             nir_constant *c =
                vtn_value(b, w[4 + i], vtn_value_type_constant)->constant;
-- 
2.14.3