Mesa (master): nir: add doubles component packing support

[Timothy Arceri]

Module: Mesa
Branch: master
Commit: cba6657d8ba57fddf72bbe3c96e8aee997a1527d
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=cba6657d8ba57fddf72bbe3c96e8aee997a1527d

Author: Timothy Arceri <timothy.arceri at collabora.com>
Date:   Tue Jul 19 15:40:14 2016 +1000

nir: add doubles component packing support

This makes sure we give the correct driver location
for doubles when using component packing. Specifically
it handles packing a dvec3 with a double which is the
only packing scenario allowed which spans across two
locations.

Acked-by: Kenneth Graunke <kenneth at whitecape.org>
Reviewed-by: Alejandro Piñeiro <apinheiro at igalia.com>

---

 src/compiler/nir/nir_lower_io.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/src/compiler/nir/nir_lower_io.c b/src/compiler/nir/nir_lower_io.c
index 4d191fe..bf8296f 100644
--- a/src/compiler/nir/nir_lower_io.c
+++ b/src/compiler/nir/nir_lower_io.c
@@ -74,6 +74,26 @@ nir_assign_var_locations(struct exec_list *var_list, unsigned *size,
          if (locations[idx][var->data.index] == -1) {
             var->data.driver_location = location;
             locations[idx][var->data.index] = location;
+
+            /* A dvec3 can be packed with a double we need special handling
+             * for this as we are packing across two locations.
+             */
+            if (glsl_get_base_type(var->type) == GLSL_TYPE_DOUBLE &&
+                glsl_get_vector_elements(var->type) == 3) {
+               /* Hack around type_size functions that expect vectors to be
+                * padded out to vec4. If a float type is the same size as a
+                * double then the type size is padded to vec4, otherwise
+                * set the offset to two doubles which offsets the location
+                * past the first two components in dvec3 which were stored at
+                * the previous location.
+                */
+               unsigned dsize = type_size(glsl_double_type());
+               unsigned offset =
+                  dsize == type_size(glsl_float_type()) ? dsize : dsize * 2;
+
+               locations[idx + 1][var->data.index] = location + offset;
+            }
+
             location += type_size(var->type);
          } else {
             var->data.driver_location = locations[idx][var->data.index];