nir: Add a helper for general instruction-modifying passes.
The nir_shader_lower_instructions() is really nice, but it's only for SSA
operations, and sometimes you want something more general. I've put it in
nir_builder.h so it can be inlined and retain the same performance
characteristics we're used to in our lowering passes even in the absence
of LTO.
Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6412>
diff --git a/src/compiler/nir/nir_builder.h b/src/compiler/nir/nir_builder.h
index 6da2e3c..af63827 100644
--- a/src/compiler/nir/nir_builder.h
+++ b/src/compiler/nir/nir_builder.h
@@ -62,6 +62,49 @@
build->cursor = nir_after_cf_list(&build->impl->body);
}
+typedef bool (*nir_instr_pass_cb)(struct nir_builder *, nir_instr *, void *);
+
+/**
+ * Iterates over all the instructions in a NIR shader and calls the given pass
+ * on them.
+ *
+ * The pass should return true if it modified the shader. In that case, only
+ * the preserved metadata flags will be preserved in the function impl.
+ *
+ * The builder will be initialized to point at the function impl, but its
+ * cursor is unset.
+ */
+static inline bool
+nir_shader_instructions_pass(nir_shader *shader,
+ nir_instr_pass_cb pass,
+ nir_metadata preserved,
+ void *cb_data)
+{
+ bool progress = false;
+
+ nir_foreach_function(function, shader) {
+ if (!function->impl)
+ continue;
+
+ nir_builder b;
+ nir_builder_init(&b, function->impl);
+
+ nir_foreach_block_safe(block, function->impl) {
+ nir_foreach_instr_safe(instr, block) {
+ progress |= pass(&b, instr, cb_data);
+ }
+ }
+
+ if (progress) {
+ nir_metadata_preserve(function->impl, preserved);
+ } else {
+ nir_metadata_preserve(function->impl, nir_metadata_all);
+ }
+ }
+
+ return progress;
+}
+
static inline void
nir_builder_instr_insert(nir_builder *build, nir_instr *instr)
{
