[Mesa-dev] [PATCH 126/133] nir: Add a foreach_ssa_def function

[Jason Ekstrand]

There are some functions whose destinations are SSA-only and so aren't a
nir_dest.  This provides a function that is capable of iterating over the
SSA definitions defined by those functions.  If you want registers, you
should use the old iterator.
---
 src/glsl/nir/nir.c | 41 +++++++++++++++++++++++++++++++++++++++++
 src/glsl/nir/nir.h |  3 +++
 2 files changed, 44 insertions(+)

diff --git a/src/glsl/nir/nir.c b/src/glsl/nir/nir.c
index 7ed811b..72a8840 100644
--- a/src/glsl/nir/nir.c
+++ b/src/glsl/nir/nir.c
@@ -1462,6 +1462,47 @@ nir_foreach_dest(nir_instr *instr, nir_foreach_dest_cb cb, void *state)
    return true;
 }
 
+struct foreach_ssa_def_state {
+   nir_foreach_ssa_def_cb cb;
+   void *client_state;
+};
+
+static inline bool
+nir_ssa_def_visitor(nir_dest *dest, void *void_state)
+{
+   struct foreach_ssa_def_state *state = void_state;
+
+   if (dest->is_ssa)
+      return state->cb(&dest->ssa, state->client_state);
+   else
+      return true;
+}
+
+bool
+nir_foreach_ssa_def(nir_instr *instr, nir_foreach_ssa_def_cb cb, void *state)
+{
+   switch (instr->type) {
+   case nir_instr_type_alu:
+   case nir_instr_type_tex:
+   case nir_instr_type_intrinsic:
+   case nir_instr_type_load_const:
+   case nir_instr_type_phi:
+   case nir_instr_type_parallel_copy: {
+      struct foreach_ssa_def_state foreach_state = {cb, state};
+      nir_foreach_dest(instr, nir_ssa_def_visitor, &foreach_state);
+      break;
+   }
+
+   case nir_instr_type_ssa_undef:
+      return cb(&nir_instr_as_ssa_undef(instr)->def, state);
+   case nir_instr_type_call:
+   case nir_instr_type_jump:
+      return true;
+   default:
+      unreachable("Invalid instruction type");
+   }
+}
+
 static bool
 visit_src(nir_src *src, nir_foreach_src_cb cb, void *state)
 {
diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
index d11299b..b859322 100644
--- a/src/glsl/nir/nir.h
+++ b/src/glsl/nir/nir.h
@@ -1317,8 +1317,11 @@ void nir_instr_insert_after_cf_list(struct exec_list *list, nir_instr *after);
 
 void nir_instr_remove(nir_instr *instr);
 
+typedef bool (*nir_foreach_ssa_def_cb)(nir_ssa_def *def, void *state);
 typedef bool (*nir_foreach_dest_cb)(nir_dest *dest, void *state);
 typedef bool (*nir_foreach_src_cb)(nir_src *src, void *state);
+bool nir_foreach_ssa_def(nir_instr *instr, nir_foreach_ssa_def_cb cb,
+                         void *state);
 bool nir_foreach_dest(nir_instr *instr, nir_foreach_dest_cb cb, void *state);
 bool nir_foreach_src(nir_instr *instr, nir_foreach_src_cb cb, void *state);
 
-- 
2.2.0