nir/lower_doubles: Use the new NIR lowering framework

One advantage of this is that we no longer need to run in a loop because
the new framework handles lowering instructions added by lowering.

Reviewed-by: Eric Anholt <eric@anholt.net>

src/compiler/nir/nir_lower_double_ops.c

@@ -424,13 +424,13 @@ lower_mod(nir_builder *b, nir_ssa_def *src0, nir_ssa_def *src1)
                     nir_imm_double(b, 0.0));
 }
 
-static bool
+static nir_ssa_def *
 lower_doubles_instr_to_soft(nir_builder *b, nir_alu_instr *instr,
                             const nir_shader *softfp64,
                             nir_lower_doubles_options options)
 {
    if (!(options & nir_lower_fp64_full_software))
-      return false;
+      return NULL;
 
    assert(instr->dest.dest.is_ssa);
 
@@ -569,8 +569,6 @@ lower_doubles_instr_to_soft(nir_builder *b, nir_alu_instr *instr,
       assert(func);
    }
 
-   b->cursor = nir_before_instr(&instr->instr);
-
    nir_ssa_def *params[4] = { NULL, };
 
    nir_variable *ret_tmp =
@@ -586,10 +584,7 @@ lower_doubles_instr_to_soft(nir_builder *b, nir_alu_instr *instr,
 
    nir_inline_function_impl(b, func->impl, params);
 
-   nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa,
+   return nir_load_deref(b, ret_deref);
-                            nir_src_for_ssa(nir_load_deref(b, ret_deref)));
-   nir_instr_remove(&instr->instr);
-   return true;
 }
 
 nir_lower_doubles_options
@@ -609,11 +604,22 @@ nir_lower_doubles_op_to_options_mask(nir_op opcode)
    }
 }
 
+struct lower_doubles_data {
+   const nir_shader *softfp64;
+   nir_lower_doubles_options options;
+};
+
 static bool
-lower_doubles_instr(nir_builder *b, nir_alu_instr *alu,
+should_lower_double_instr(const nir_instr *instr, const void *_data)
-                    const nir_shader *softfp64,
-                    nir_lower_doubles_options options)
 {
+   const struct lower_doubles_data *data = _data;
+   const nir_lower_doubles_options options = data->options;
+
+   if (instr->type != nir_instr_type_alu)
+      return false;
+
+   const nir_alu_instr *alu = nir_instr_as_alu(instr);
+
    assert(alu->dest.dest.is_ssa);
    bool is_64 = alu->dest.dest.ssa.bit_size == 64;
 
@@ -625,58 +631,56 @@ lower_doubles_instr(nir_builder *b, nir_alu_instr *alu,
    if (!is_64)
       return false;
 
-   if (lower_doubles_instr_to_soft(b, alu, softfp64, options))
+   if (options & nir_lower_fp64_full_software)
       return true;
 
-   if (!(options & nir_lower_doubles_op_to_options_mask(alu->op)))
+   return options & nir_lower_doubles_op_to_options_mask(alu->op);
-      return false;
+}
 
-   b->cursor = nir_before_instr(&alu->instr);
+static nir_ssa_def *
+lower_doubles_instr(nir_builder *b, nir_instr *instr, void *_data)
+{
+   const struct lower_doubles_data *data = _data;
+   const nir_lower_doubles_options options = data->options;
+   nir_alu_instr *alu = nir_instr_as_alu(instr);
+
+   nir_ssa_def *soft_def =
+      lower_doubles_instr_to_soft(b, alu, data->softfp64, options);
+   if (soft_def)
+      return soft_def;
+
+   if (!(options & nir_lower_doubles_op_to_options_mask(alu->op)))
+      return NULL;
 
    nir_ssa_def *src = nir_mov_alu(b, alu->src[0],
                                   alu->dest.dest.ssa.num_components);
 
-   nir_ssa_def *result;
-
    switch (alu->op) {
    case nir_op_frcp:
-      result = lower_rcp(b, src);
+      return lower_rcp(b, src);
-      break;
    case nir_op_fsqrt:
-      result = lower_sqrt_rsq(b, src, true);
+      return lower_sqrt_rsq(b, src, true);
-      break;
    case nir_op_frsq:
-      result = lower_sqrt_rsq(b, src, false);
+      return lower_sqrt_rsq(b, src, false);
-      break;
    case nir_op_ftrunc:
-      result = lower_trunc(b, src);
+      return lower_trunc(b, src);
-      break;
    case nir_op_ffloor:
-      result = lower_floor(b, src);
+      return lower_floor(b, src);
-      break;
    case nir_op_fceil:
-      result = lower_ceil(b, src);
+      return lower_ceil(b, src);
-      break;
    case nir_op_ffract:
-      result = lower_fract(b, src);
+      return lower_fract(b, src);
-      break;
    case nir_op_fround_even:
-      result = lower_round_even(b, src);
+      return lower_round_even(b, src);
-      break;
 
    case nir_op_fmod: {
       nir_ssa_def *src1 = nir_mov_alu(b, alu->src[1],
                                       alu->dest.dest.ssa.num_components);
-      result = lower_mod(b, src, src1);
+      return lower_mod(b, src, src1);
    }
-      break;
    default:
       unreachable("unhandled opcode");
    }
-
-   nir_ssa_def_rewrite_uses(&alu->dest.dest.ssa, nir_src_for_ssa(result));
-   nir_instr_remove(&alu->instr);
-   return true;
 }
 
 static bool
@@ -684,21 +688,18 @@ nir_lower_doubles_impl(nir_function_impl *impl,
                        const nir_shader *softfp64,
                        nir_lower_doubles_options options)
 {
-   bool progress = false;
+   struct lower_doubles_data data = {
+      .softfp64 = softfp64,
+      .options = options,
+   };
 
-   nir_builder b;
+   bool progress =
-   nir_builder_init(&b, impl);
+      nir_function_impl_lower_instructions(impl,
+                                           should_lower_double_instr,
+                                           lower_doubles_instr,
+                                           &data);
 
-   nir_foreach_block_safe(block, impl) {
+   if (progress && (options & nir_lower_fp64_full_software)) {
-      nir_foreach_instr_safe(instr, block) {
-         if (instr->type == nir_instr_type_alu)
-            progress |= lower_doubles_instr(&b, nir_instr_as_alu(instr),
-                                            softfp64, options);
-      }
-   }
-
-   if (progress) {
-      if (options & nir_lower_fp64_full_software) {
       /* SSA and register indices are completely messed up now */
       nir_index_ssa_defs(impl);
       nir_index_local_regs(impl);
@@ -709,14 +710,6 @@ nir_lower_doubles_impl(nir_function_impl *impl,
        * inlining.
        */
       nir_opt_deref_impl(impl);
-      } else {
-         nir_metadata_preserve(impl, nir_metadata_block_index |
-                                     nir_metadata_dominance);
-      }
-    } else {
-#ifndef NDEBUG
-      impl->valid_metadata &= ~nir_metadata_not_properly_reset;
-#endif
    }
 
    return progress;