[Mesa-dev] [RFC] nir/register: Add a parent_instr field
Jason Ekstrand
jason at jlekstrand.net
Thu Jan 29 21:45:53 PST 2015
This adds a parent_instr field similar to the one for ssa_def. The
difference here is that the parent_instr field on a nir_register can be
NULL if the register does not have a unique definition or if that
definition does not dominate all its uses. We set this field in the
out-of-SSA pass so that backends can get SSA-like information even after
they have gone out of SSA.
---
Note: This has not been compile-tested
src/glsl/nir/nir.c | 1 +
src/glsl/nir/nir.h | 11 ++++++++++-
src/glsl/nir/nir_from_ssa.c | 7 +++++++
3 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/src/glsl/nir/nir.c b/src/glsl/nir/nir.c
index 25cdac0..b3b825b 100644
--- a/src/glsl/nir/nir.c
+++ b/src/glsl/nir/nir.c
@@ -61,6 +61,7 @@ reg_create(void *mem_ctx, struct exec_list *list)
{
nir_register *reg = ralloc(mem_ctx, nir_register);
+ reg->parent_instr = NULL;
reg->uses = _mesa_set_create(mem_ctx, _mesa_hash_pointer,
_mesa_key_pointer_equal);
reg->defs = _mesa_set_create(mem_ctx, _mesa_hash_pointer,
diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
index 980fdd0..2c7ffdc 100644
--- a/src/glsl/nir/nir.h
+++ b/src/glsl/nir/nir.h
@@ -64,6 +64,7 @@ name(const in_type *parent) \
struct nir_function_overload;
struct nir_function;
struct nir_shader;
+struct nir_instr;
/**
@@ -384,6 +385,14 @@ typedef struct {
*/
bool is_packed;
+ /**
+ * If this pointer is non-NULL then this register has exactly one
+ * definition and that definition dominates all of its uses. This is
+ * set by the out-of-SSA pass so that backends can get SSA-like
+ * information even once they have gone out of SSA.
+ */
+ struct nir_instr *parent_instr;
+
/** set of nir_instr's where this register is used (read from) */
struct set *uses;
@@ -406,7 +415,7 @@ typedef enum {
nir_instr_type_parallel_copy,
} nir_instr_type;
-typedef struct {
+typedef struct nir_instr {
struct exec_node node;
nir_instr_type type;
struct nir_block *block;
diff --git a/src/glsl/nir/nir_from_ssa.c b/src/glsl/nir/nir_from_ssa.c
index 2e7add3..f0105fb 100644
--- a/src/glsl/nir/nir_from_ssa.c
+++ b/src/glsl/nir/nir_from_ssa.c
@@ -513,6 +513,13 @@ get_register_for_ssa_def(nir_ssa_def *def, struct from_ssa_state *state)
reg->num_components = def->num_components;
reg->num_array_elems = 0;
+ /* This register comes from an SSA definition that was not part of a
+ * phi-web. Therefore, we know it has a single unique definition
+ * that dominates all of its uses. Therefore, we can copy the
+ * parent_instr from the SSA def safely.
+ */
+ reg->parent_instr = def->parent_instr;
+
_mesa_hash_table_insert(state->ssa_table, def, reg);
return reg;
}
--
2.1.0
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