[Mesa-dev] [PATCH] spirv: Handle doubles when multiplying a mat by a scalar

[Neil Roberts]

The code to handle mat multipication by a scalar tries to pick either
imul or fmul depending on whether the matrix is float or integer.
However it was doing this by checking whether the base type is float.
This was making it choose the int path for doubles (and presumably
float16s).

---

This was discovered from running the arb_gpu_shader_fp64 tests through
the GL_ARB_gl_spirv branch. For example:
arb_gpu_shader_fp64 at execution@built-in-functions at vs-op-div-dmat4-double.
Note however these tests are hidden behind a glslang bug:

https://github.com/KhronosGroup/glslang/issues/1278

The fix in that issue along with this patch makes them all pass.

There’s also a little test case for this with VkRunner here:

https://github.com/Igalia/vkrunner/blob/tests/examples/dmat-mul-scalar.shader_test

 src/compiler/spirv/vtn_alu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/compiler/spirv/vtn_alu.c b/src/compiler/spirv/vtn_alu.c
index d0c9e316935..110fcec2a60 100644
--- a/src/compiler/spirv/vtn_alu.c
+++ b/src/compiler/spirv/vtn_alu.c
@@ -142,10 +142,10 @@ mat_times_scalar(struct vtn_builder *b,
 {
    struct vtn_ssa_value *dest = vtn_create_ssa_value(b, mat->type);
    for (unsigned i = 0; i < glsl_get_matrix_columns(mat->type); i++) {
-      if (glsl_get_base_type(mat->type) == GLSL_TYPE_FLOAT)
-         dest->elems[i]->def = nir_fmul(&b->nb, mat->elems[i]->def, scalar);
-      else
+      if (glsl_base_type_is_integer(glsl_get_base_type(mat->type)))
          dest->elems[i]->def = nir_imul(&b->nb, mat->elems[i]->def, scalar);
+      else
+         dest->elems[i]->def = nir_fmul(&b->nb, mat->elems[i]->def, scalar);
    }
 
    return dest;
-- 
2.14.3