Mesa (master): aco: don't create byte-aligned short loads

[GitLab Mirror]

Module: Mesa
Branch: master
Commit: 91d7e40176328d0a256d9b9cf0ff749604035c51
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=91d7e40176328d0a256d9b9cf0ff749604035c51

Author: Rhys Perry <pendingchaos02 at gmail.com>
Date:   Thu Jun 11 15:38:07 2020 +0100

aco: don't create byte-aligned short loads

The ISA docs don't seem to say if this is allowed, so just assume short
loads require short alignment.

In practice, the only situation this should affect are byte-aligned u8vec2
loads.

Signed-off-by: Rhys Perry <pendingchaos02 at gmail.com>
Reviewed-by: Daniel Schürmann <daniel at schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5207>

---

 src/amd/compiler/aco_instruction_selection.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/amd/compiler/aco_instruction_selection.cpp b/src/amd/compiler/aco_instruction_selection.cpp
index b36c41d8474..0af920b5629 100644
--- a/src/amd/compiler/aco_instruction_selection.cpp
+++ b/src/amd/compiler/aco_instruction_selection.cpp
@@ -3111,7 +3111,9 @@ void emit_load(isel_context *ctx, Builder& bld, const LoadEmitInfo *info)
       int byte_align = align_mul % 4 == 0 ? align_offset % 4 : -1;
 
       if (byte_align) {
-         if ((bytes_needed > 2 || !supports_8bit_16bit_loads) && byte_align_loads) {
+         if ((bytes_needed > 2 ||
+              (bytes_needed == 2 && (align_mul % 2 || align_offset % 2)) ||
+              !supports_8bit_16bit_loads) && byte_align_loads) {
             if (info->component_stride) {
                assert(supports_8bit_16bit_loads && "unimplemented");
                bytes_needed = 2;