nir: Add some new helpers for working with const sources

Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

src/compiler/nir/nir.c

@@ -1198,6 +1198,98 @@ nir_foreach_src(nir_instr *instr, nir_foreach_src_cb cb, void *state)
    return nir_foreach_dest(instr, visit_dest_indirect, &dest_state);
 }
 
+int64_t
+nir_src_comp_as_int(nir_src src, unsigned comp)
+{
+   assert(nir_src_is_const(src));
+   nir_load_const_instr *load = nir_instr_as_load_const(src.ssa->parent_instr);
+
+   assert(comp < load->def.num_components);
+   switch (load->def.bit_size) {
+   case 8:  return load->value.i8[comp];
+   case 16: return load->value.i16[comp];
+   case 32: return load->value.i32[comp];
+   case 64: return load->value.i64[comp];
+   default:
+      unreachable("Invalid bit size");
+   }
+}
+
+uint64_t
+nir_src_comp_as_uint(nir_src src, unsigned comp)
+{
+   assert(nir_src_is_const(src));
+   nir_load_const_instr *load = nir_instr_as_load_const(src.ssa->parent_instr);
+
+   assert(comp < load->def.num_components);
+   switch (load->def.bit_size) {
+   case 8:  return load->value.u8[comp];
+   case 16: return load->value.u16[comp];
+   case 32: return load->value.u32[comp];
+   case 64: return load->value.u64[comp];
+   default:
+      unreachable("Invalid bit size");
+   }
+}
+
+bool
+nir_src_comp_as_bool(nir_src src, unsigned comp)
+{
+   assert(nir_src_is_const(src));
+   nir_load_const_instr *load = nir_instr_as_load_const(src.ssa->parent_instr);
+
+   assert(comp < load->def.num_components);
+   assert(load->def.bit_size == 32);
+   assert(load->value.u32[comp] == NIR_TRUE ||
+          load->value.u32[comp] == NIR_FALSE);
+
+   return load->value.u32[comp];
+}
+
+double
+nir_src_comp_as_float(nir_src src, unsigned comp)
+{
+   assert(nir_src_is_const(src));
+   nir_load_const_instr *load = nir_instr_as_load_const(src.ssa->parent_instr);
+
+   assert(comp < load->def.num_components);
+   switch (load->def.bit_size) {
+   case 16: return _mesa_half_to_float(load->value.u16[comp]);
+   case 32: return load->value.f32[comp];
+   case 64: return load->value.f64[comp];
+   default:
+      unreachable("Invalid bit size");
+   }
+}
+
+int64_t
+nir_src_as_int(nir_src src)
+{
+   assert(nir_src_num_components(src) == 1);
+   return nir_src_comp_as_int(src, 0);
+}
+
+uint64_t
+nir_src_as_uint(nir_src src)
+{
+   assert(nir_src_num_components(src) == 1);
+   return nir_src_comp_as_uint(src, 0);
+}
+
+bool
+nir_src_as_bool(nir_src src)
+{
+   assert(nir_src_num_components(src) == 1);
+   return nir_src_comp_as_bool(src, 0);
+}
+
+double
+nir_src_as_float(nir_src src)
+{
+   assert(nir_src_num_components(src) == 1);
+   return nir_src_comp_as_float(src, 0);
+}
+
 nir_const_value *
 nir_src_as_const_value(nir_src src)
 {

src/compiler/nir/nir.h

@@ -700,6 +700,22 @@ nir_src_num_components(nir_src src)
    return src.is_ssa ? src.ssa->num_components : src.reg.reg->num_components;
 }
 
+static inline bool
+nir_src_is_const(nir_src src)
+{
+   return src.is_ssa &&
+          src.ssa->parent_instr->type == nir_instr_type_load_const;
+}
+
+int64_t nir_src_as_int(nir_src src);
+uint64_t nir_src_as_uint(nir_src src);
+bool nir_src_as_bool(nir_src src);
+double nir_src_as_float(nir_src src);
+int64_t nir_src_comp_as_int(nir_src src, unsigned component);
+uint64_t nir_src_comp_as_uint(nir_src src, unsigned component);
+bool nir_src_comp_as_bool(nir_src src, unsigned component);
+double nir_src_comp_as_float(nir_src src, unsigned component);
+
 static inline unsigned
 nir_dest_bit_size(nir_dest dest)
 {