Mesa (master): aco: fix non-rtz pack_half_2x16

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Module: Mesa
Branch: master
Commit: 9c1e0d86a813af7609acf42cfe6bec7401d6405f
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=9c1e0d86a813af7609acf42cfe6bec7401d6405f

Author: Rhys Perry <pendingchaos02 at gmail.com>
Date:   Mon Aug 17 11:28:07 2020 +0100

aco: fix non-rtz pack_half_2x16

We were using the wrong conversion opcode. The high bits are also not
zero'd on GFX10, which can cause v_cvt_pk_u16_u32 to clamp.

Signed-off-by: Rhys Perry <pendingchaos02 at gmail.com>
Reviewed-by: Daniel Schürmann <daniel at schuermann.dev>
Fixes: df645fa369d ('aco: implement VK_KHR_shader_float_controls')
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6346>

---

 src/amd/compiler/aco_instruction_selection.cpp | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/amd/compiler/aco_instruction_selection.cpp b/src/amd/compiler/aco_instruction_selection.cpp
index 7d45f5b8c33..5bd389a5be4 100644
--- a/src/amd/compiler/aco_instruction_selection.cpp
+++ b/src/amd/compiler/aco_instruction_selection.cpp
@@ -2714,12 +2714,18 @@ void visit_alu_instr(isel_context *ctx, nir_alu_instr *instr)
          Temp src0 = bld.tmp(v1);
          Temp src1 = bld.tmp(v1);
          bld.pseudo(aco_opcode::p_split_vector, Definition(src0), Definition(src1), src);
-         if (!ctx->block->fp_mode.care_about_round32 || ctx->block->fp_mode.round32 == fp_round_tz)
+         if (0 && (!ctx->block->fp_mode.care_about_round32 || ctx->block->fp_mode.round32 == fp_round_tz)) {
             bld.vop3(aco_opcode::v_cvt_pkrtz_f16_f32, Definition(dst), src0, src1);
-         else
-            bld.vop3(aco_opcode::v_cvt_pk_u16_u32, Definition(dst),
-                     bld.vop1(aco_opcode::v_cvt_f32_f16, bld.def(v1), src0),
-                     bld.vop1(aco_opcode::v_cvt_f32_f16, bld.def(v1), src1));
+         } else {
+            src0 = bld.vop1(aco_opcode::v_cvt_f16_f32, bld.def(v1), src0);
+            src1 = bld.vop1(aco_opcode::v_cvt_f16_f32, bld.def(v1), src1);
+            if (ctx->program->chip_class >= GFX10) {
+               /* the high bits of v_cvt_f16_f32 isn't zero'd on GFX10 */
+               bld.vop3(aco_opcode::v_pack_b32_f16, Definition(dst), src0, src1);
+            } else {
+               bld.vop3(aco_opcode::v_cvt_pk_u16_u32, Definition(dst), src0, src1);
+            }
+         }
       } else {
          isel_err(&instr->instr, "Unimplemented NIR instr bit size");
       }