[Mesa-dev] [PATCH 02/10] nir: Add a loop analysis pass
Jason Ekstrand
jason at jlekstrand.net
Sat Sep 17 00:52:24 UTC 2016
On Fri, Sep 16, 2016 at 5:36 PM, Connor Abbott <cwabbott0 at gmail.com> wrote:
> On Fri, Sep 16, 2016 at 6:25 PM, Jason Ekstrand <jason at jlekstrand.net>
> wrote:
> > On Thu, Sep 15, 2016 at 12:03 AM, Timothy Arceri
> > <timothy.arceri at collabora.com> wrote:
> >>
> >> From: Thomas Helland <thomashelland90 at gmail.com>
> >>
> >> This pass detects induction variables and calculates the
> >> trip count of loops to be used for loop unrolling.
> >>
> >> I've removed support for float induction values for now, for the
> >> simple reason that they don't appear in my shader-db collection,
> >> and so I don't see it as common enough that we want to pollute the
> >> pass with this in the initial version.
> >>
> >> V2: Rebase, adapt to removal of function overloads
> >>
> >> V3: (Timothy Arceri)
> >> - don't try to find trip count if loop terminator conditional is a phi
> >> - fix trip count for do-while loops
> >> - replace conditional type != alu assert with return
> >> - disable unrolling of loops with continues
> >> - multiple fixes to memory allocation, stop leaking and don't destroy
> >> structs we want to use for unrolling.
> >> - fix iteration count bugs when induction var not on RHS of condition
> >> - add FIXME for && conditions
> >> - calculate trip count for unsigned induction/limit vars
> >>
> >> V4:
> >> - count instructions in a loop
> >> - set the limiting_terminator even if we can't find the trip count for
> >> all terminators. This is needed for complex unrolling where we handle
> >> 2 terminators and the trip count is unknown for one of them.
> >> - restruct structs so we don't keep information not required after
> >> analysis and remove dead fields.
> >> - force unrolling in some cases as per the rules in the GLSL IR pass
> >> ---
> >> src/compiler/Makefile.sources | 2 +
> >> src/compiler/nir/nir.h | 36 +-
> >> src/compiler/nir/nir_loop_analyze.c | 1012
> >> +++++++++++++++++++++++++++++++++++
> >> src/compiler/nir/nir_metadata.c | 8 +-
> >> 4 files changed, 1056 insertions(+), 2 deletions(-)
> >> create mode 100644 src/compiler/nir/nir_loop_analyze.c
> >>
> >> diff --git a/src/compiler/Makefile.sources b/src/compiler/Makefile.
> sources
> >> index f5b4f9c..7ed26a9 100644
> >> --- a/src/compiler/Makefile.sources
> >> +++ b/src/compiler/Makefile.sources
> >> @@ -190,6 +190,8 @@ NIR_FILES = \
> >> nir/nir_intrinsics.c \
> >> nir/nir_intrinsics.h \
> >> nir/nir_liveness.c \
> >> + nir/nir_loop_analyze.c \
> >> + nir/nir_loop_analyze.h \
> >> nir/nir_lower_alu_to_scalar.c \
> >> nir/nir_lower_atomics.c \
> >> nir/nir_lower_bitmap.c \
> >> diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
> >> index ff7c422..49e8cd8 100644
> >> --- a/src/compiler/nir/nir.h
> >> +++ b/src/compiler/nir/nir.h
> >> @@ -1549,9 +1549,36 @@ nir_if_last_else_node(nir_if *if_stmt)
> >> }
> >>
> >> typedef struct {
> >> + nir_if *nif;
> >> +
> >> + nir_instr *conditional_instr;
> >> +
> >> + struct list_head loop_terminator_link;
> >> +} nir_loop_terminator;
> >> +
> >> +typedef struct {
> >> + /* Number of instructions in the loop */
> >> + unsigned num_instructions;
> >> +
> >> + /* How many times the loop is run (if known) */
> >> + unsigned trip_count;
> >> + bool is_trip_count_known;
> >
> >
> > We could use 0 or -1 to indicate "I don't know trip count" instead of an
> > extra boolean. Not sure that it matters much.
> >
> >>
> >> +
> >> + /* Unroll the loop regardless of its size */
> >> + bool force_unroll;
> >
> >
> > It seems a bit odd to have this decide to force-unroll. This is an
> analysis
> > pass, not a "make decisions" pass.
> >
> >>
> >> +
> >> + nir_loop_terminator *limiting_terminator;
> >> +
> >> + /* A list of loop_terminators terminating this loop. */
> >> + struct list_head loop_terminator_list;
> >> +} nir_loop_info;
> >> +
> >> +typedef struct {
> >> nir_cf_node cf_node;
> >>
> >> struct exec_list body; /** < list of nir_cf_node */
> >> +
> >> + nir_loop_info *info;
> >> } nir_loop;
> >>
> >> static inline nir_cf_node *
> >> @@ -1576,6 +1603,7 @@ typedef enum {
> >> nir_metadata_dominance = 0x2,
> >> nir_metadata_live_ssa_defs = 0x4,
> >> nir_metadata_not_properly_reset = 0x8,
> >> + nir_metadata_loop_analysis = 0x16,
> >> } nir_metadata;
> >>
> >> typedef struct {
> >> @@ -1758,6 +1786,8 @@ typedef struct nir_shader_compiler_options {
> >> * information must be inferred from the list of input
> nir_variables.
> >> */
> >> bool use_interpolated_input_intrinsics;
> >> +
> >> + unsigned max_unroll_iterations;
> >> } nir_shader_compiler_options;
> >>
> >> typedef struct nir_shader_info {
> >> @@ -1962,7 +1992,7 @@ nir_loop *nir_loop_create(nir_shader *shader);
> >> nir_function_impl *nir_cf_node_get_function(nir_cf_node *node);
> >>
> >> /** requests that the given pieces of metadata be generated */
> >> -void nir_metadata_require(nir_function_impl *impl, nir_metadata
> >> required);
> >> +void nir_metadata_require(nir_function_impl *impl, nir_metadata
> required,
> >> ...);
> >> /** dirties all but the preserved metadata */
> >> void nir_metadata_preserve(nir_function_impl *impl, nir_metadata
> >> preserved);
> >>
> >> @@ -2559,6 +2589,10 @@ void nir_lower_double_pack(nir_shader *shader);
> >> bool nir_normalize_cubemap_coords(nir_shader *shader);
> >>
> >> void nir_live_ssa_defs_impl(nir_function_impl *impl);
> >> +
> >> +void nir_loop_analyze_impl(nir_function_impl *impl,
> >> + nir_variable_mode indirect_mask);
> >> +
> >> bool nir_ssa_defs_interfere(nir_ssa_def *a, nir_ssa_def *b);
> >>
> >> void nir_convert_to_ssa_impl(nir_function_impl *impl);
> >> diff --git a/src/compiler/nir/nir_loop_analyze.c
> >> b/src/compiler/nir/nir_loop_analyze.c
> >> new file mode 100644
> >> index 0000000..6bea9e5
> >> --- /dev/null
> >> +++ b/src/compiler/nir/nir_loop_analyze.c
> >> @@ -0,0 +1,1012 @@
> >> +/*
> >> + * Copyright © 2015 Thomas Helland
> >> + *
> >> + * Permission is hereby granted, free of charge, to any person
> obtaining
> >> a
> >> + * copy of this software and associated documentation files (the
> >> "Software"),
> >> + * to deal in the Software without restriction, including without
> >> limitation
> >> + * the rights to use, copy, modify, merge, publish, distribute,
> >> sublicense,
> >> + * and/or sell copies of the Software, and to permit persons to whom
> the
> >> + * Software is furnished to do so, subject to the following conditions:
> >> + *
> >> + * The above copyright notice and this permission notice (including the
> >> next
> >> + * paragraph) shall be included in all copies or substantial portions
> of
> >> the
> >> + * Software.
> >> + *
> >> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> >> EXPRESS OR
> >> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> >> MERCHANTABILITY,
> >> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
> >> SHALL
> >> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
> >> OTHER
> >> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> >> ARISING
> >> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> >> DEALINGS
> >> + * IN THE SOFTWARE.
> >> + */
> >> +
> >> +#include "nir.h"
> >> +
> >> +typedef enum {
> >> + undefined,
> >> + invariant,
> >> + basic_induction
> >> +} nir_loop_variable_type;
> >> +
> >> +typedef struct {
> >> + /* The ssa_def associated with this info */
> >> + nir_ssa_def *def;
> >> +
> >> + /* The type of this ssa_def */
> >> + nir_loop_variable_type type;
> >> +
> >> + /* If the ssa-def is constant */
> >> + bool is_constant;
> >> +
> >> + bool in_conditional_block;
> >> +
> >> + bool in_nested_loop;
> >> +} nir_loop_variable;
> >> +
> >> +typedef struct {
> >> + nir_op alu_op; /* The type of
> alu-operation
> >> */
> >> + nir_loop_variable *alu_def; /* The def of the
> >> alu-operation */
> >> + nir_loop_variable *invariant; /* The invariant
> alu-operand
> >> */
> >> + nir_loop_variable *phi; /* The other alu-operand
> >> */
> >> + nir_loop_variable *def_outside_loop; /* The phi-src outside the
> >> loop */
> >> +} nir_basic_induction_var;
> >> +
> >> +typedef struct {
> >> + /* A link for the work list */
> >> + struct list_head process_link;
> >> +
> >> + bool in_loop;
> >> +
> >> + nir_loop_variable *nir_loop_var;
> >> +} loop_variable;
> >> +
> >> +typedef struct {
> >> + bool contains_break;
> >> + bool contains_continue;
> >> +} loop_jumps;
> >> +
> >> +typedef struct {
> >> + /* The loop we store information for */
> >> + nir_loop *loop;
> >> +
> >> + /* Loop_variable for all ssa_defs in function */
> >> + loop_variable *loop_vars;
> >> +
> >> + /* Loop_variable for all ssa_defs in function */
> >> + nir_loop_variable *nir_loop_vars;
> >
> >
> > Why are these two separate things? You have two arrays both indexed by
> > nir_ssa_def::index and both called loop_vars and one has a pointer to the
> > other. Can we just make 1 array?
> >
> >>
> >> +
> >> + /* A list of the loop_vars to analyze */
> >> + struct list_head process_list;
> >> +
> >> + nir_loop_info *info;
> >> +
> >> + nir_variable_mode indirect_mask;
> >> +
> >> + struct hash_table *var_to_basic_ind;
> >
> >
> > Also, this seems like an unneeded level of indirection. Just put a
> pointer
> > in loop_variable that points to the induction var struct.
> >
> >>
> >> +} loop_info_state;
> >> +
> >> +static loop_variable *
> >> +get_loop_var(nir_ssa_def *value, loop_info_state *state)
> >> +{
> >> + return &(state->loop_vars[value->index]);
> >> +}
> >> +
> >> +static nir_loop_variable *
> >> +get_nir_loop_var(nir_ssa_def *value, loop_info_state *state)
> >> +{
> >> + return &(state->nir_loop_vars[value->index]);
> >> +}
> >> +
> >> +typedef struct {
> >> + loop_info_state *state;
> >> + bool mark_nested;
> >> + bool mark_in_conditional;
> >> +} init_loop_state;
> >> +
> >> +static bool
> >> +init_loop_def(nir_ssa_def *def, void *void_init_loop_state)
> >> +{
> >> + init_loop_state *loop_init_state = void_init_loop_state;
> >> + loop_variable *var = get_loop_var(def, loop_init_state->state);
> >> +
> >> + /* Add to the tail of the list. That way we start at the beginning
> of
> >> the
> >> + * defs in the loop instead of the end when walking the list. This
> >> means
> >> + * less recursive calls. Only add defs that are not in nested loops
> or
> >> + * conditional blocks.
> >> + */
> >> + if (!(loop_init_state->mark_in_conditional ||
> >> + loop_init_state->mark_nested))
> >> + LIST_ADDTAIL(&(var->process_link),
> >> + &(loop_init_state->state->process_list));
> >
> >
> > I have a mild preference for the lower-case variants. As I recall, they
> are
> > more for legacy.
> >
> >>
> >> +
> >> + if (loop_init_state->mark_in_conditional)
> >> + var->nir_loop_var->in_conditional_block = true;
> >> +
> >> + if (loop_init_state->mark_nested)
> >> + var->nir_loop_var->in_nested_loop = true;
> >> +
> >> + var->in_loop = true;
> >> +
> >> + return true;
> >> +}
> >> +
> >> +static bool
> >> +init_loop_block(nir_block *block, void *void_init_loop_state)
> >
> >
> > Can we make this function take the actual parameters and limit
> > init_loop_state to being the thing we use for init_loop_def. Passing
> piles
> > of pointers through made sense when Thomas originally wrote it but now
> that
> > we have better loop iteration macros, we can just pass arguments.
> >
> >>
> >> +{
> >> + init_loop_state *loop_init_state = void_init_loop_state;
> >> +
> >> + nir_foreach_instr(instr, block)
> >> + nir_foreach_ssa_def(instr, init_loop_def, loop_init_state);
> >> +
> >> + return true;
> >> +}
> >> +
> >> +static inline bool
> >> +is_var_alu(loop_variable *var)
> >> +{
> >> + return (var->nir_loop_var->def->parent_instr->type ==
> >> nir_instr_type_alu);
> >> +}
> >> +
> >> +static inline bool
> >> +is_var_phi(loop_variable *var)
> >> +{
> >> + return (var->nir_loop_var->def->parent_instr->type ==
> >> nir_instr_type_phi);
> >> +}
> >> +
> >> +static inline bool
> >> +is_ssa_def_invariant(nir_ssa_def *def, loop_info_state *state)
> >> +{
> >> + loop_variable *var = get_loop_var(def, state);
> >> +
> >> + if (var->nir_loop_var->type == invariant)
> >> + return true;
> >> +
> >> + if (!var->in_loop) {
> >> + var->nir_loop_var->type = invariant;
> >> + return true;
> >> + }
> >> +
> >> + if (var->nir_loop_var->type == basic_induction)
> >> + return false;
> >> +
> >> + if (is_var_alu(var)) {
> >> + nir_alu_instr *alu = nir_instr_as_alu(def->parent_instr);
> >> +
> >> + for (unsigned i = 0; i < nir_op_infos[alu->op].num_inputs; i++)
> {
> >> + if (!is_ssa_def_invariant(alu->src[i].src.ssa, state))
> >> + return false;
> >> + }
> >> + var->nir_loop_var->type = invariant;
> >> + return true;
> >> + }
> >> +
> >> + /* Phis shouldn't be invariant except if one operand is invariant,
> and
> >> the
> >> + * other is the phi itself. These should be removed by
> >> opt_remove_phis.
> >> + * load_consts are already set to invariant and constant during
> init,
> >> + * and so should return earlier. Remaining op_codes are set
> undefined.
> >> + */
> >> + var->nir_loop_var->type = undefined;
> >> + return false;
> >> +}
> >> +
> >> +static void
> >> +compute_invariance_information(loop_info_state *state)
> >> +{
> >> + /* An expression is invariant in a loop L if:
> >> + * (base cases)
> >> + * – it’s a constant
> >> + * – it’s a variable use, all of whose single defs are outside
> of L
> >> + * (inductive cases)
> >> + * – it’s a pure computation all of whose args are loop invariant
> >> + * – it’s a variable use whose single reaching def, and the
> >> + * rhs of that def is loop-invariant
> >> + */
> >> + bool changes;
> >> +
> >> + do {
> >> + changes = false;
> >> + list_for_each_entry_safe(loop_variable, var,
> >> + &state->process_list, process_link) {
> >> +
> >> + if (var->nir_loop_var->in_conditional_block ||
> >> + var->nir_loop_var->in_nested_loop) {
> >> + LIST_DEL(&var->process_link);
> >> + continue;
> >> + }
> >> +
> >> + if (is_ssa_def_invariant(var->nir_loop_var->def, state)) {
> >> + LIST_DEL(&var->process_link);
> >> + changes = true;
> >> + }
> >> + }
> >> + } while (changes);
> >> +}
> >> +
> >> +static inline bool
> >> +is_var_basic_induction_var(loop_variable *var, loop_info_state *state)
> >> +{
> >> + if (var->nir_loop_var->type == basic_induction)
> >> + return true;
> >> +
> >> + /* We are only interested in checking phi's for the basic induction
> >> + * variable case as its simple to detect. All basic induction
> >> variables
> >> + * have a phi node
> >> + */
> >> + if (!is_var_phi(var))
> >> + return false;
> >> +
> >> + nir_phi_instr *phi =
> >> nir_instr_as_phi(var->nir_loop_var->def->parent_instr);
> >> +
> >> + nir_basic_induction_var *biv = rzalloc(state,
> >> nir_basic_induction_var);
> >> + biv->phi = var->nir_loop_var;
> >> +
> >> + nir_foreach_phi_src(src, phi) {
> >> + loop_variable *src_var = get_loop_var(src->src.ssa, state);
> >> +
> >> + /* If one of the sources is in a conditional or nested block then
> >> panic.
> >> + */
> >> + if (src_var->nir_loop_var->in_conditional_block ||
> >> + src_var->nir_loop_var->in_nested_loop)
> >> + break;
> >> +
> >> + if (!src_var->in_loop)
> >> + biv->def_outside_loop = src_var->nir_loop_var;
> >
> >
> > Could we assert biv->def_outside_loop == NULL
> >
> >>
> >> +
> >> + if (src_var->in_loop && is_var_alu(src_var)) {
> >> + nir_alu_instr *alu =
> >> + nir_instr_as_alu(src_var->nir_
> loop_var->def->parent_instr);
> >> +
> >> + switch (alu->op) {
> >> + case nir_op_fadd: case nir_op_iadd: case
> >> nir_op_uadd_carry:
> >> + case nir_op_fsub: case nir_op_isub: case
> >> nir_op_usub_borrow:
> >> + case nir_op_fmul: case nir_op_imul: case
> nir_op_umul_high:
> >> + case nir_op_fdiv: case nir_op_idiv: case nir_op_udiv:
> >
> >
> > Is there a reason why this is an explicit list and not simply
> > "nir_op_infos[alu->op].num_inputs == 2"?
> >
> >>
> >> +
> >> + biv->alu_def = src_var->nir_loop_var;
> >> +
> >> + for (unsigned i = 0; i < 2; i++) {
> >> + /* Is one of the operands invariant, and the other the
> phi
> >> */
> >> + if (is_ssa_def_invariant(alu->src[i].src.ssa, state) &&
> >> + alu->src[1-i].src.ssa->index == phi->dest.ssa.index)
> >> + biv->invariant = get_nir_loop_var(alu->src[i].
> src.ssa,
> >> + state);
> >> + }
> >> +
> >> + biv->alu_op = alu->op;
> >> + break;
> >> + default:
> >> + break;
> >> + }
> >> + }
> >> + }
> >> +
> >> + if (biv->alu_def && biv->def_outside_loop && biv->invariant &&
> >> biv->phi) {
> >> + biv->alu_def->type = basic_induction;
> >> + biv->phi->type = basic_induction;
> >> + _mesa_hash_table_insert(state->var_to_basic_ind, biv->alu_def,
> >> biv);
> >> + _mesa_hash_table_insert(state->var_to_basic_ind, biv->phi, biv);
> >> + return true;
> >> + }
> >> +
> >> + /* The requirements for a basic induction variable are not fulfilled
> >> */
> >> + ralloc_free(biv);
> >> + return false;
> >> +}
> >> +
> >> +static bool
> >> +compute_induction_information(loop_info_state *state)
> >> +{
> >> + bool changes;
> >> + bool found_induction_var = false;
> >> +
> >> + do {
> >> + changes = false;
> >> + list_for_each_entry_safe(loop_variable, var,
> >> + &state->process_list, process_link) {
> >> +
> >> + /* It can't be an induction variable if it is invariant. We
> >> don't
> >> + * want to deal with things in nested loops or conditionals.
> >> + */
> >> + if (var->nir_loop_var->type == invariant ||
> >> + var->nir_loop_var->in_conditional_block ||
> >> + var->nir_loop_var->in_nested_loop) {
> >> + LIST_DEL(&(var->process_link));
> >> + continue;
> >> + }
> >> +
> >> + if (is_var_basic_induction_var(var, state)) {
> >> + /* If a phi is marked basic_ind we also mark the alu_def
> >> basic_ind
> >> + * at the same time. It will then be detected as basic_ind
> >> here,
> >> + * on the second passing, and be removed from the list.
> >> + */
> >> + LIST_DEL(&(var->process_link));
> >> + changes = true;
> >> + found_induction_var = true;
> >> + }
> >> + }
> >> + } while (changes);
> >> +
> >> + return found_induction_var;
> >> +}
> >> +
> >> +static bool
> >> +initialize_ssa_def(nir_ssa_def *def, void *void_state)
> >> +{
> >> + loop_info_state *state = void_state;
> >> + loop_variable *var = get_loop_var(def, state);
> >> +
> >> + var->nir_loop_var = get_nir_loop_var(def, state);
> >> +
> >> + var->in_loop = false;
> >> + var->nir_loop_var->def = def;
> >> +
> >> + if (def->parent_instr->type == nir_instr_type_load_const) {
> >> + var->nir_loop_var->type = invariant;
> >> + var->nir_loop_var->is_constant = true;
> >> + } else {
> >> + var->nir_loop_var->type = undefined;
> >> + }
> >> +
> >> + return true;
> >> +}
> >> +
> >> +static bool
> >> +foreach_cf_node_ex_loop(nir_cf_node *node, void *state)
> >
> >
> > There's no good reason for this to be a void *; it just leads to extra
> > casting. Also, this function could use a better name. Maybe
> > cf_node_find_loop_jumps?
> >
> >>
> >> +{
> >> + nir_block *block;
> >> +
> >> + switch (node->type) {
> >> + case nir_cf_node_block:
> >> + block = nir_cf_node_as_block(node);
> >> + nir_foreach_instr(instr, block) {
> >
> >
> > Jumps are always the last instruction in a block. There's no sense in
> > walking all of them just to find the jump. Use nir_block_last_instr()
> > instead.
> >
> >>
> >> + if (instr->type == nir_instr_type_jump) {
> >> + if (nir_instr_as_jump(instr)->type == nir_jump_break) {
> >> + ((loop_jumps *) state)->contains_break = true;
> >> + } else if (nir_instr_as_jump(instr)->type ==
> >> nir_jump_continue) {
> >> + ((loop_jumps *) state)->contains_continue = true;
> >> + }
> >> + }
> >> + }
> >> + return true;
> >> +
> >> + case nir_cf_node_if: {
> >> + nir_if *if_stmt = nir_cf_node_as_if(node);
> >> +
> >> + foreach_list_typed_safe(nir_cf_node, node, node,
> >> &if_stmt->then_list)
> >> + if (!foreach_cf_node_ex_loop(node, state))
> >> + return false;
> >> +
> >> + foreach_list_typed_safe(nir_cf_node, node, node,
> >> &if_stmt->else_list)
> >> + if (!foreach_cf_node_ex_loop(node, state))
> >> + return false;
> >> +
> >> + break;
> >> + }
> >
> >
> > Maybe add an explicit case for nir_cf_node_loop with a comment that we
> don't
> > care about inner loops.
> >
> >>
> >> +
> >> + default:
> >> + break;
> >> + }
> >> +
> >> + return false;
> >> +}
> >> +
> >> +static bool
> >> +is_trivial_loop_terminator(nir_if *nif)
> >> +{
> >> + /* If there is stuff in the else-block that means that this is not a
> >> + * simple break on true if-statement and so we bail
> >> + */
> >> + foreach_list_typed_safe(nir_cf_node, node, node, &nif->else_list)
> >> + if (node->type == nir_cf_node_block)
> >> + nir_foreach_instr(instr, nir_cf_node_as_block(node))
> >> + return false;
> >
> >
> > How about "if (!exec_list_empty(&nif->else_list)) return false;"? That
> > seems far simpler.
>
> That won't work, since cf lists are never empty. I think the intent
> was to check that the else branch consists of one empty basic block,
> in which case it's broken -- it could have just a loop, for example,
> and we wouldn't return false. I think what you want to do is get the
> first node, cast it to a basic block, bail if it has any instructions,
> and then bail if it doesn't equal the last node.
>
You are correct, sir. That is what I meant.
> >
> >>
> >> +
> >> + nir_cf_node *first_then = nir_if_first_then_node(nif);
> >> + nir_block *first_then_block = nir_cf_node_as_block(first_then);
> >> + nir_instr *first_instr = nir_block_first_instr(first_then_block);
> >> +
> >> + if (first_instr && first_instr->type == nir_instr_type_jump &&
> >> + nir_instr_as_jump(first_instr)->type == nir_jump_break) {
> >> + return true;
> >> + }
> >> +
> >> + return false;
> >> +}
> >> +
> >> +static bool
> >> +find_loop_terminators(loop_info_state *state)
> >> +{
> >> + bool success = false;
> >> + foreach_list_typed_safe(nir_cf_node, node, node,
> &state->loop->body) {
> >> + if (node->type == nir_cf_node_if) {
> >> + nir_if *nif = nir_cf_node_as_if(node);
> >> +
> >> + /* Don't check the nested loops if there are breaks */
> >> + loop_jumps lj;
> >> + lj.contains_break = false;
> >> + lj.contains_continue = false;
> >> +
> >> + foreach_cf_node_ex_loop(&nif->cf_node, &lj);
> >> +
> >> + if (lj.contains_continue)
> >> + return false;
> >> +
> >> + if (!lj.contains_break)
> >> + continue;
> >> +
> >> + /* If there is a break then we should find a terminator. If we
> >> can
> >> + * not find a loop terminator, but there is a break-statement
> >> then
> >> + * we should return false so that we do not try to find
> >> trip-count
> >> + */
> >> + if (!is_trivial_loop_terminator(nif))
> >> + return false;
> >> +
> >> + if (nif->condition.ssa->parent_instr->type ==
> >> nir_instr_type_phi)
> >> + return false;
> >> +
> >> + nir_loop_terminator *terminator =
> >> + rzalloc(state->info, nir_loop_terminator);
> >> +
> >> + list_add(&terminator->loop_terminator_link,
> >> + &state->info->loop_terminator_list);
> >> +
> >> + terminator->nif = nif;
> >> + terminator->conditional_instr =
> >> nif->condition.ssa->parent_instr;
> >> +
> >> + success = true;
> >> + }
> >> + }
> >> +
> >> + return success;
> >> +}
> >> +
> >> +static nir_basic_induction_var *
> >> +get_basic_ind_var_for_loop_var(loop_variable *var, loop_info_state
> >> *state)
> >> +{
> >> + assert(var->nir_loop_var->type == basic_induction);
> >> +
> >> + struct hash_entry *entry =
> >> + _mesa_hash_table_search(state->var_to_basic_ind,
> >> var->nir_loop_var);
> >> +
> >> + return entry->data;
> >> +}
> >> +
> >> +static int32_t
> >> +get_iteration(nir_op cond_op, nir_const_value *initial, nir_const_value
> >> *step,
> >> + nir_const_value *limit, nir_alu_instr *alu, int32_t
> >> *init_val,
> >> + bool increment_before)
> >> +{
> >> + int32_t iter;
> >> +
> >> + switch (cond_op) {
> >> + case nir_op_ige:
> >> + case nir_op_ilt:
> >> + case nir_op_ieq:
> >> + case nir_op_ine: {
> >> + int32_t initial_val = initial->i32[0];
> >> + if (increment_before) {
> >> + initial_val = alu->op == nir_op_iadd ?
> >> + initial_val + step->i32[0] : initial_val - step->i32[0];
> >> + }
> >> +
> >> + int32_t span = limit->i32[0] - initial_val;
> >> + iter = span / step->i32[0];
> >> + *init_val = initial_val;
> >> + break;
> >> + }
> >> + case nir_op_uge:
> >> + case nir_op_ult: {
> >> + uint32_t initial_val = initial->u32[0];
> >> + if (increment_before) {
> >> + initial_val = alu->op == nir_op_iadd ?
> >> + initial_val + step->u32[0] : initial_val - step->u32[0];
> >> + }
> >> +
> >> + uint32_t span = limit->u32[0] - initial_val;
> >> + iter = span / step->u32[0];
> >> + *init_val = initial_val;
> >> + break;
> >> + }
> >> + default:
> >> + return -1;
> >> + }
> >> +
> >> + return iter;
> >> +}
> >> +
> >> +static uint32_t
> >> +utest_interations(int32_t iter_int, nir_const_value *step,
> >> + nir_const_value *limit, nir_op cond_op,
> >> + uint32_t initial_val, bool limit_rhs)
> >> +{
> >> + bool valid_loop = false;
> >> + uint32_t mul = iter_int * step->u32[0];
> >> + uint32_t uadd = mul + initial_val;
> >> +
> >> + switch (cond_op) {
> >> + case nir_op_uge:
> >> + valid_loop = limit_rhs ? uadd >= limit->u32[0] : uadd <=
> >> limit->u32[0];
> >> + break;
> >> + case nir_op_ult:
> >> + valid_loop = limit_rhs ? uadd < limit->u32[0] : uadd >
> >> limit->u32[0];
> >> + break;
> >> + default:
> >> + unreachable("Unhandled loop condition!");
> >> + }
> >> +
> >> + return valid_loop;
> >> +}
> >> +
> >> +static int32_t
> >> +itest_interations(int32_t iter_int, nir_const_value *step,
> >> + nir_const_value *limit, nir_op cond_op,
> >> + int32_t initial_val, bool limit_rhs)
> >> +{
> >> + bool valid_loop = false;
> >> + int32_t mul = iter_int * step->i32[0];
> >> + int32_t iadd = mul + initial_val;
> >> +
> >> + switch (cond_op) {
> >> + case nir_op_ige:
> >> + valid_loop = limit_rhs ? iadd >= limit->i32[0] : iadd <=
> >> limit->i32[0];
> >> + break;
> >> + case nir_op_ilt:
> >> + valid_loop = limit_rhs ? iadd < limit->i32[0] : iadd >
> >> limit->i32[0];
> >> + break;
> >> + case nir_op_ieq:
> >> + valid_loop = iadd == limit->i32[0];
> >> + break;
> >> + case nir_op_ine:
> >> + valid_loop = iadd != limit->i32[0];
> >> + break;
> >> + default:
> >> + unreachable("Unhandled loop condition!");
> >> + }
> >> +
> >> + return valid_loop;
> >> +}
> >> +
> >> +static int
> >> +calculate_iterations(nir_const_value *initial, nir_const_value *step,
> >> + nir_const_value *limit, nir_op cond_op,
> >> + nir_loop_variable *alu_def, nir_alu_instr
> *cond_alu,
> >> + bool limit_rhs)
> >> +{
> >> + assert(initial != NULL && step != NULL && limit != NULL);
> >> +
> >> + nir_alu_instr *alu = nir_instr_as_alu(alu_def->def->parent_instr);
> >> +
> >> + /* Unsupported alu operation */
> >> + if (!(alu->op == nir_op_iadd || alu->op == nir_op_isub))
> >
> >
> > You only allow iadd and isub except that we lower away isub so you'll
> never
> > see it. Probably best to remove the dead code. Also...
> >
> > 1) You don't handle swizzles at all
> > 2) You don't handle things other than 64 or 16-bit. Those are coming
> soon;
> > they need to be supported.
> >
> >>
> >> + return -1;
> >> +
> >> + /* do-while loops can increment the starting value before the
> >> condition is
> >> + * checked. e.g.
> >> + *
> >> + * do {
> >> + * ndx++;
> >> + * } while (ndx < 3);
> >> + *
> >> + * Here we check if the induction variable is used directly by the
> >> loop
> >> + * condition and if so we assume we need to step the initial value.
> >> + */
> >> + bool increment_before = false;
> >> + if (cond_alu->src[0].src.ssa == alu_def->def ||
> >> + cond_alu->src[1].src.ssa == alu_def->def) {
> >> + increment_before = true;
> >
> >
> > Is there a reason why this can't be handled as "trip_count + 1"? This
> seems
> > way overcomplicated.
> >
> >>
> >> + }
> >> +
> >> + int32_t initial_val;
> >> + int iter_int = get_iteration(cond_op, initial, step, limit, alu,
> >> + &initial_val, increment_before);
> >> +
> >> + /* If iter_int is negative the loop is ill-formed or is the
> >> conditional is
> >> + * unsigned with a huge iteration count so don't bother going any
> >> further.
> >> + */
> >> + if (iter_int < 0)
> >> + return -1;
> >> +
> >> + /* An explanation from the GLSL unrolling pass:
> >> + *
> >> + * Make sure that the calculated number of iterations satisfies the
> >> exit
> >> + * condition. This is needed to catch off-by-one errors and some
> >> types of
> >> + * ill-formed loops. For example, we need to detect that the
> >> following
> >> + * loop does not have a maximum iteration count.
> >> + *
> >> + * for (float x = 0.0; x != 0.9; x += 0.2);
> >> + */
> >> + const int bias[] = { -1, 1, 1 };
> >> +
> >> + for (unsigned i = 0; i < ARRAY_SIZE(bias); i++) {
> >> + iter_int = iter_int + bias[i];
> >> +
> >> + switch (cond_op) {
> >> + case nir_op_ige:
> >> + case nir_op_ilt:
> >> + case nir_op_ieq:
> >> + case nir_op_ine:
> >> + if (itest_interations(iter_int, step, limit, cond_op,
> >> initial_val,
> >> + limit_rhs)) {
> >> + return iter_int;
> >> + }
> >> + break;
> >> + case nir_op_uge:
> >> + case nir_op_ult:
> >> + if (utest_interations(iter_int, step, limit, cond_op,
> >> + (uint32_t) initial_val, limit_rhs)) {
> >> + return iter_int;
> >
> >
> > I think it would be clearer if we combined these two functions.
> >
> >>
> >> + }
> >> + break;
> >> + default:
> >> + return -1;
> >> + }
> >> + }
> >> +
> >> + return -1;
> >> +}
> >> +
> >> +/* Run through each of the terminators of the loop and try to infer a
> >> possible
> >> + * trip-count. We need to check them all, and set the lowest trip-count
> >> as the
> >> + * trip-count of our loop. If one of the terminators has an undecidable
> >> + * trip-count we can not safely assume anything about the duration of
> the
> >> + * loop.
> >> + */
> >> +static void
> >> +find_trip_count(loop_info_state *state)
> >> +{
> >> + bool trip_count_known = true;
> >> + nir_loop_terminator *limiting_terminator = NULL;
> >> + int min_trip_count = -2;
> >> +
> >> + list_for_each_entry(nir_loop_terminator, terminator,
> >> + &state->info->loop_terminator_list,
> >> + loop_terminator_link) {
> >> +
> >> + if (terminator->conditional_instr->type != nir_instr_type_alu) {
> >> + /* If we get here the loop is likely not really a loop and
> will
> >> get
> >> + * cleaned up elsewhere.
> >> + */
> >
> >
> > The if statement (and its contents) seem fine but the comment here seems
> > sketchy.
> >
> >>
> >> + trip_count_known = false;
> >> + continue;
> >> + }
> >> +
> >> + nir_alu_instr *alu =
> >> nir_instr_as_alu(terminator->conditional_instr);
> >> + loop_variable *basic_ind = NULL;
> >> + loop_variable *limit = NULL;
> >> + bool limit_rhs = true;
> >> + nir_op cond_op;
> >> +
> >> + switch (alu->op) {
> >> + case nir_op_fge: case nir_op_ige: case nir_op_uge:
> >> + case nir_op_flt: case nir_op_ilt: case nir_op_ult:
> >> + case nir_op_feq: case nir_op_ieq:
> >> + case nir_op_fne: case nir_op_ine:
> >> +
> >> + /* We assume that the limit is the "right" operand */
> >> + basic_ind = get_loop_var(alu->src[0].src.ssa, state);
> >> + limit = get_loop_var(alu->src[1].src.ssa, state);
> >> + cond_op = alu->op;
> >> +
> >> + if (basic_ind->nir_loop_var->type != basic_induction) {
> >> + /* We had it the wrong way, flip things around */
> >> + basic_ind = get_loop_var(alu->src[1].src.ssa, state);
> >> + limit = get_loop_var(alu->src[0].src.ssa, state);
> >> + limit_rhs = false;
> >> + }
> >> +
> >> + /* The comparison has to have a basic induction variable
> >> + * and a constant for us to be able to find trip counts
> >> + */
> >> + if (basic_ind->nir_loop_var->type != basic_induction ||
> >> + !limit->nir_loop_var->is_constant) {
> >> + trip_count_known = false;
> >> + continue;
> >> + }
> >> +
> >> + nir_basic_induction_var *ind =
> >> + get_basic_ind_var_for_loop_var(basic_ind, state);
> >> +
> >> + if (!ind->def_outside_loop->is_constant ||
> >> + !ind->invariant->is_constant) {
> >> + trip_count_known = false;
> >> + continue;
> >> + }
> >> +
> >> + /* We have determined that we have the following constants:
> >> + * (With the typical int i = 0; i < x; i++; as an example)
> >> + * - Upper limit.
> >> + * - Starting value
> >> + * - Step / iteration size
> >> + * Thats all thats needed to calculate the trip-count
> >> + */
> >> +
> >> + nir_load_const_instr *initial_instr =
> >> + nir_instr_as_load_const(
> >> + ind->def_outside_loop->def->parent_instr);
> >> +
> >> + nir_const_value initial_val = initial_instr->value;
> >> +
> >> + nir_load_const_instr *step_instr =
> >> + nir_instr_as_load_const(
> >> + ind->invariant->def->parent_instr);
> >> +
> >> + nir_const_value step_val = step_instr->value;
> >> +
> >> + nir_load_const_instr *limit_instr =
> >> + nir_instr_as_load_const(
> >> + limit->nir_loop_var->def->parent_instr);
> >> +
> >> + nir_const_value limit_val = limit_instr->value;
> >> +
> >> + int iterations = calculate_iterations(&initial_val,
> &step_val,
> >> + &limit_val, cond_op,
> >> + ind->alu_def, alu,
> >> limit_rhs);
> >> +
> >> + /* Where we not able to calculate the iteration count */
> >> + if (iterations == -1) {
> >> + trip_count_known = false;
> >> + continue;
> >> + }
> >> +
> >> + /* If this is the first run or we have found a smaller amount
> of
> >> + * iterations than previously (we have identified a more
> >> limiting
> >> + * terminator) set the trip count and limiting terminator.
> >> + */
> >> + if (min_trip_count == -2 || iterations < min_trip_count) {
> >
> >
> > Can we have a #define for -2 so that it has a name.
> >
> >>
> >> + min_trip_count = iterations;
> >> + limiting_terminator = terminator;
> >> + }
> >> + break;
> >> +
> >> + default:
> >> + trip_count_known = false;
> >> + }
> >> + }
> >> +
> >> + state->info->is_trip_count_known = trip_count_known;
> >> + if (min_trip_count > -2)
> >> + state->info->trip_count = min_trip_count;
> >> + state->info->limiting_terminator = limiting_terminator;
> >> +}
> >> +
> >> +/* Checks if we should force the loop to be unrolled regardless of size
> >> */
> >> +static bool
> >> +force_unroll(loop_info_state *state, nir_shader *ns, nir_deref_var
> >> *variable)
> >> +{
> >> + nir_deref *tail = &variable->deref;
> >> +
> >> + while (tail->child != NULL) {
> >> + tail = tail->child;
> >> +
> >> + if (tail->deref_type == nir_deref_type_array) {
> >> +
> >> + nir_deref_array *deref_array = nir_deref_as_array(tail);
> >> + if (deref_array->deref_array_type !=
> >> nir_deref_array_type_indirect)
> >> + continue;
> >> +
> >> + nir_loop_variable *array_index =
> >> + get_nir_loop_var(deref_array->indirect.ssa, state);
> >> +
> >> + if (array_index->type != basic_induction)
> >> + continue;
> >> +
> >> + /* If an array is indexed by a loop induction variable, and
> the
> >> + * array size is exactly the number of loop iterations, this
> is
> >> + * probably a simple for-loop trying to access each element in
> >> + * turn; the application may expect it to be unrolled.
> >> + */
> >> + if (glsl_get_length(tail->type) == state->info->trip_count) {
> >> + state->info->force_unroll = true;
> >> + return state->info->force_unroll;
> >> + }
> >> +
> >> + if (variable->var->data.mode & state->indirect_mask) {
> >> + state->info->force_unroll = true;
> >> + return state->info->force_unroll;
> >> + }
> >
> >
> > Thinking a bit about analysis vs. lowering...
> >
> > I wonder if it wouldn't be better to make the loop anlaysis pass be a bit
> > more informational and less decision making. For instance, it could
> record
> > what all variable modes it has seen be indexed by an induction variable
> and
> > let the pass using the analysis decide whether or not to force-unroll.
> For
> > that matter, it could just produce a hash map from induction variables to
> > the loop for which they are an induction variable. You could also just
> > record the trip count per-loop. That all seems a bit more like things an
> > analysis pass would do than just setting a force_unroll bit.
> >
> > Please don't feel like you need to make any changes in this direction
> yet.
> > I'm mostly trying to open the discussion up a bit and feel out exactly
> how
> > we want things to be structured.
> >
> > I think I've written you a long enough book for now. I'll try to look at
> > the others as I get time.
> >
> > --Jason
> >
> >>
> >> + }
> >> + }
> >> +
> >> + return false;
> >> +}
> >> +
> >> +static bool
> >> +count_instructions(loop_info_state *state, nir_shader *ns, nir_block
> >> *block)
> >> +{
> >> + nir_foreach_instr(instr, block) {
> >> + if (instr->type == nir_instr_type_intrinsic ||
> >> + instr->type == nir_instr_type_alu) {
> >> + state->info->num_instructions++;
> >> + }
> >> +
> >> + if (instr->type != nir_instr_type_intrinsic)
> >> + continue;
> >> +
> >> + nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
> >> +
> >> + /* Check for arrays variably-indexed by a loop induction
> variable.
> >> + * Unrolling the loop may convert that access into
> >> constant-indexing.
> >> + */
> >> + if (intrin->intrinsic == nir_intrinsic_load_var ||
> >> + intrin->intrinsic == nir_intrinsic_store_var ||
> >> + intrin->intrinsic == nir_intrinsic_copy_var) {
> >> + unsigned num_vars =
> >> + nir_intrinsic_infos[intrin->intrinsic].num_variables;
> >> + for (unsigned i = 0; i < num_vars; i++) {
> >> + if (force_unroll(state, ns, intrin->variables[i]))
> >> + return true;
> >> + }
> >> + }
> >> + }
> >> +
> >> + return false;
> >> +}
> >> +
> >> +static void
> >> +get_loop_info(loop_info_state *state, nir_function_impl *impl)
> >> +{
> >> + /* Initialize all variables to "outside_loop". This also marks defs
> >> + * invariant and constant if they are nir_instr_type_load_const's
> >> + */
> >> + nir_foreach_block(block, impl) {
> >> + nir_foreach_instr(instr, block)
> >> + nir_foreach_ssa_def(instr, initialize_ssa_def, state);
> >> + }
> >> +
> >> + init_loop_state init_state = {.mark_in_conditional = false,
> >> + .mark_nested = false, .state = state
> };
> >> +
> >> + /* Add all entries in the outermost part of the loop to the
> processing
> >> list
> >> + * Mark the entries in conditionals or in nested loops accordingly
> >> + */
> >> + foreach_list_typed_safe(nir_cf_node, node, node,
> &state->loop->body) {
> >> + switch (node->type) {
> >> +
> >> + case nir_cf_node_block:
> >> + init_state.mark_in_conditional = false;
> >> + init_state.mark_nested = false;
> >> + init_loop_block(nir_cf_node_as_block(node), &init_state);
> >> + break;
> >> +
> >> + case nir_cf_node_if:
> >> + init_state.mark_in_conditional = true;
> >> + init_state.mark_nested = false;
> >> + nir_foreach_block_in_cf_node(block, node)
> >> + init_loop_block(block, &init_state);
> >> + break;
> >> +
> >> + case nir_cf_node_loop:
> >> + init_state.mark_in_conditional = false;
> >> + init_state.mark_nested = true;
> >> + nir_foreach_block_in_cf_node(block, node) {
> >> + init_loop_block(block, &init_state);
> >> + }
> >> + break;
> >> +
> >> + case nir_cf_node_function:
> >> + break;
> >> + }
> >> + }
> >> +
> >> + /* Induction analysis needs invariance information so get that first
> >> */
> >> + compute_invariance_information(state);
> >> +
> >> + /* We may now have filled the process_list with instructions from
> >> inside
> >> + * the nested blocks in the loop. Remove all instructions from the
> >> list
> >> + * nir_foreach_block_in_cf_node before we start computing induction
> >> + * information.
> >> + */
> >> + list_inithead(&state->process_list);
> >> +
> >> + /* Add all entries in the outermost part of the loop to the
> processing
> >> list.
> >> + * Don't include defs inn nested loops or in conditionals.
> >> + */
> >> + init_state.mark_in_conditional = false;
> >> + init_state.mark_nested = false;
> >> +
> >> + foreach_list_typed_safe(nir_cf_node, node, node,
> &state->loop->body)
> >> + if (node->type == nir_cf_node_block)
> >> + init_loop_block(nir_cf_node_as_block(node), &init_state);
> >> +
> >> + /* We have invariance information so try to find induction variables
> >> */
> >> + if (!compute_induction_information(state))
> >> + return;
> >> +
> >> + /* Try to find all simple terminators of the loop. If we can't find
> >> any,
> >> + * or we find possible terminators that have side effects then bail.
> >> + */
> >> + if (!find_loop_terminators(state))
> >> + return;
> >> +
> >> + /* Run through each of the terminators and try to compute a
> trip-count
> >> */
> >> + find_trip_count(state);
> >> +
> >> + nir_shader *ns = impl->function->shader;
> >> + foreach_list_typed_safe(nir_cf_node, node, node,
> &state->loop->body) {
> >> + if (node->type == nir_cf_node_block) {
> >> + if (count_instructions(state, ns, nir_cf_node_as_block(node)))
> >> + break;
> >> + } else {
> >> + nir_foreach_block_in_cf_node(block, node) {
> >> + if (count_instructions(state, ns, block))
> >> + break;
> >> + }
> >> + }
> >> + }
> >> +}
> >> +
> >> +static loop_info_state *
> >> +initialize_loop_info_state(nir_loop *loop, void *mem_ctx,
> >> nir_function_impl *impl)
> >> +{
> >> + loop_info_state *state = rzalloc(mem_ctx, loop_info_state);
> >> + state->loop_vars = rzalloc_array(mem_ctx, loop_variable,
> >> impl->ssa_alloc);
> >> + state->loop = loop;
> >> + state->nir_loop_vars = rzalloc_array(mem_ctx, nir_loop_variable,
> >> + impl->ssa_alloc);
> >> +
> >> + LIST_INITHEAD(&state->process_list);
> >> +
> >> + if (loop->info)
> >> + ralloc_free(loop->info);
> >> +
> >> + state->info = rzalloc(loop, nir_loop_info);
> >> +
> >> + LIST_INITHEAD(&state->info->loop_terminator_list);
> >> +
> >> + state->var_to_basic_ind =
> >> + _mesa_hash_table_create(state->info, _mesa_hash_pointer,
> >> + _mesa_key_pointer_equal);
> >> +
> >> + return state;
> >> +}
> >> +
> >> +static void
> >> +process_loops(nir_cf_node *cf_node, nir_variable_mode indirect_mask)
> >> +{
> >> + switch (cf_node->type) {
> >> + case nir_cf_node_block:
> >> + return;
> >> + case nir_cf_node_if: {
> >> + nir_if *if_stmt = nir_cf_node_as_if(cf_node);
> >> + foreach_list_typed(nir_cf_node, nested_node, node,
> >> &if_stmt->then_list)
> >> + process_loops(nested_node, indirect_mask);
> >> + foreach_list_typed(nir_cf_node, nested_node, node,
> >> &if_stmt->else_list)
> >> + process_loops(nested_node, indirect_mask);
> >> + return;
> >> + }
> >> + case nir_cf_node_loop: {
> >> + nir_loop *loop = nir_cf_node_as_loop(cf_node);
> >> + foreach_list_typed(nir_cf_node, nested_node, node, &loop->body)
> >> + process_loops(nested_node, indirect_mask);
> >> + break;
> >> + }
> >> + default:
> >> + unreachable("unknown cf node type");
> >> + }
> >> +
> >> + nir_loop *loop = nir_cf_node_as_loop(cf_node);
> >> + nir_function_impl *impl = nir_cf_node_get_function(cf_node);
> >> + void *mem_ctx = ralloc_context(NULL);
> >> +
> >> + loop_info_state *state = initialize_loop_info_state(loop, mem_ctx,
> >> impl);
> >> + state->indirect_mask = indirect_mask;
> >> +
> >> + get_loop_info(state, impl);
> >> +
> >> + loop->info = state->info;
> >> +
> >> + ralloc_free(mem_ctx);
> >> +}
> >> +
> >> +void
> >> +nir_loop_analyze_impl(nir_function_impl *impl,
> >> + nir_variable_mode indirect_mask)
> >> +{
> >> + if (impl->function->shader->options->max_unroll_iterations == 0)
> >> + return;
> >> +
> >> + nir_index_ssa_defs(impl);
> >> + foreach_list_typed(nir_cf_node, node, node, &impl->body)
> >> + process_loops(node, indirect_mask);
> >> +}
> >> diff --git a/src/compiler/nir/nir_metadata.c
> >> b/src/compiler/nir/nir_metadata.c
> >> index 9e1cff5..f71cf43 100644
> >> --- a/src/compiler/nir/nir_metadata.c
> >> +++ b/src/compiler/nir/nir_metadata.c
> >> @@ -31,7 +31,7 @@
> >> */
> >>
> >> void
> >> -nir_metadata_require(nir_function_impl *impl, nir_metadata required)
> >> +nir_metadata_require(nir_function_impl *impl, nir_metadata required,
> ...)
> >> {
> >> #define NEEDS_UPDATE(X) ((required & ~impl->valid_metadata) & (X))
> >>
> >> @@ -41,6 +41,12 @@ nir_metadata_require(nir_function_impl *impl,
> >> nir_metadata required)
> >> nir_calc_dominance_impl(impl);
> >> if (NEEDS_UPDATE(nir_metadata_live_ssa_defs))
> >> nir_live_ssa_defs_impl(impl);
> >> + if (NEEDS_UPDATE(nir_metadata_loop_analysis)) {
> >> + va_list ap;
> >> + va_start(ap, required);
> >> + nir_loop_analyze_impl(impl, va_arg(ap, nir_variable_mode));
> >> + va_end(ap);
> >> + }
> >>
> >> #undef NEEDS_UPDATE
> >>
> >> --
> >> 2.7.4
> >>
> >> _______________________________________________
> >> mesa-dev mailing list
> >> mesa-dev at lists.freedesktop.org
> >> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
> >
> >
> >
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
> >
>
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