Mesa (master): i965/fs: shuffle_32bit_load_result_to_16bit_data now skips components

[Jason Ekstrand]

Module: Mesa
Branch: master
Commit: 2dd94f462b0069fc3a20c9a93a9cfe97dd079837
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=2dd94f462b0069fc3a20c9a93a9cfe97dd079837

Author: Jose Maria Casanova Crespo <jmcasanova at igalia.com>
Date:   Mon Feb 26 20:28:34 2018 +0100

i965/fs: shuffle_32bit_load_result_to_16bit_data now skips components

This helper used to load 16bit components from 32-bits read now allows
skipping components with the new parameter first_component. The semantics
now skip components until we reach the first_component, and then reads the
number of components passed to the function.

All previous uses of the helper are updated to use 0 as first_component.
This will allow read 16-bit components when the first one is not aligned
32-bit. Enabling more usages of untyped_reads with 16-bit types.

v2: (Jason Ektrand)
    Change parameters order to first_component, num_components

Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>

---

 src/intel/compiler/brw_fs.cpp     | 2 +-
 src/intel/compiler/brw_fs.h       | 1 +
 src/intel/compiler/brw_fs_nir.cpp | 6 ++++--
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/intel/compiler/brw_fs.cpp b/src/intel/compiler/brw_fs.cpp
index 113f62c46c..244c6cda03 100644
--- a/src/intel/compiler/brw_fs.cpp
+++ b/src/intel/compiler/brw_fs.cpp
@@ -194,7 +194,7 @@ fs_visitor::VARYING_PULL_CONSTANT_LOAD(const fs_builder &bld,
    fs_reg dw = offset(vec4_result, bld, (const_offset & 0xf) / 4);
    switch (type_sz(dst.type)) {
    case 2:
-      shuffle_32bit_load_result_to_16bit_data(bld, dst, dw, 1);
+      shuffle_32bit_load_result_to_16bit_data(bld, dst, dw, 0, 1);
       bld.MOV(dst, subscript(dw, dst.type, (const_offset / 2) & 1));
       break;
    case 4:
diff --git a/src/intel/compiler/brw_fs.h b/src/intel/compiler/brw_fs.h
index 76ad76e08b..38e9991df7 100644
--- a/src/intel/compiler/brw_fs.h
+++ b/src/intel/compiler/brw_fs.h
@@ -505,6 +505,7 @@ fs_reg shuffle_64bit_data_for_32bit_write(const brw::fs_builder &bld,
 void shuffle_32bit_load_result_to_16bit_data(const brw::fs_builder &bld,
                                              const fs_reg &dst,
                                              const fs_reg &src,
+                                             uint32_t first_component,
                                              uint32_t components);
 
 void shuffle_16bit_data_for_32bit_write(const brw::fs_builder &bld,
diff --git a/src/intel/compiler/brw_fs_nir.cpp b/src/intel/compiler/brw_fs_nir.cpp
index d8300589a5..0d1ab5b01c 100644
--- a/src/intel/compiler/brw_fs_nir.cpp
+++ b/src/intel/compiler/brw_fs_nir.cpp
@@ -2316,7 +2316,7 @@ do_untyped_vector_read(const fs_builder &bld,
          shuffle_32bit_load_result_to_16bit_data(bld,
                retype(dest, BRW_REGISTER_TYPE_W),
                retype(read_result, BRW_REGISTER_TYPE_D),
-               num_components);
+               0, num_components);
       } else {
          assert(num_components == 1);
          /* scalar 16-bit are read using one byte_scattered_read message */
@@ -4912,6 +4912,7 @@ void
 shuffle_32bit_load_result_to_16bit_data(const fs_builder &bld,
                                         const fs_reg &dst,
                                         const fs_reg &src,
+                                        uint32_t first_component,
                                         uint32_t components)
 {
    assert(type_sz(src.type) == 4);
@@ -4926,7 +4927,8 @@ shuffle_32bit_load_result_to_16bit_data(const fs_builder &bld,
 
    for (unsigned i = 0; i < components; i++) {
       const fs_reg component_i =
-         subscript(offset(src, bld, i / 2), dst.type, i % 2);
+         subscript(offset(src, bld, (first_component + i) / 2), dst.type,
+                   (first_component + i) % 2);
 
       bld.MOV(offset(tmp, bld, i % 2), component_i);