aco: Implement scalar iadd_sat.

Signed-off-by: Georg Lehmann <dadschoorse@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15421>

diff --git a/src/amd/compiler/aco_instruction_selection.cpp b/src/amd/compiler/aco_instruction_selection.cpp
index 05abb20..99be353 100644 (file)
--- a/src/amd/compiler/aco_instruction_selection.cpp
+++ b/src/amd/compiler/aco_instruction_selection.cpp
@@ -1902,7 +1902,20 @@ visit_alu_instr(isel_context* ctx, nir_alu_instr* instr)
    }
    case nir_op_iadd_sat: {
       Temp src0 = get_alu_src(ctx, instr->src[0]);
-      Temp src1 = as_vgpr(ctx, get_alu_src(ctx, instr->src[1]));
+      Temp src1 = get_alu_src(ctx, instr->src[1]);
+      if (dst.regClass() == s1) {
+         Temp cond = bld.sopc(aco_opcode::s_cmp_lt_i32, bld.def(s1, scc), src1, Operand::zero());
+         Temp bound = bld.sop2(aco_opcode::s_add_u32, bld.def(s1), bld.scc(bld.def(s1, scc)),
+                               Operand::c32(INT32_MAX), cond);
+         Temp overflow = bld.tmp(s1);
+         Temp add =
+            bld.sop2(aco_opcode::s_add_i32, bld.def(s1), bld.scc(Definition(overflow)), src0, src1);
+         bld.sop2(aco_opcode::s_cselect_b32, Definition(dst), bound, add, bld.scc(overflow));
+         break;
+      }
+
+      src1 = as_vgpr(ctx, src1);
+
       if (dst.regClass() == v2b) {
          Instruction* add_instr =
             bld.vop3(aco_opcode::v_add_i16, Definition(dst), src0, src1).instr;

diff --git a/src/amd/compiler/aco_instruction_selection_setup.cpp b/src/amd/compiler/aco_instruction_selection_setup.cpp
index 5e1b068..6d0efad 100644 (file)
--- a/src/amd/compiler/aco_instruction_selection_setup.cpp
+++ b/src/amd/compiler/aco_instruction_selection_setup.cpp
@@ -534,7 +534,6 @@ init_context(isel_context* ctx, nir_shader* shader)
                case nir_op_cube_face_index_amd:
                case nir_op_cube_face_coord_amd:
                case nir_op_sad_u8x4:
-               case nir_op_iadd_sat:
                case nir_op_udot_4x8_uadd:
                case nir_op_sdot_4x8_iadd:
                case nir_op_udot_4x8_uadd_sat: