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[NFC] Clean up the fusion cut methods - documentation, style
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Signed-off-by: Uday Bondhugula <[email protected]>
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bondhugula committed Mar 2, 2021
1 parent 61a0218 commit dae26e7
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Showing 3 changed files with 32 additions and 45 deletions.
2 changes: 1 addition & 1 deletion lib/ddg.h
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Original file line number Diff line number Diff line change
Expand Up @@ -39,7 +39,7 @@ struct scc {
int size;

/* Maximum dimensionality statement in this SCC */
int max_dim;
unsigned max_dim;

/* Id of this SCC */
int id;
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71 changes: 29 additions & 42 deletions lib/pluto.c
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Original file line number Diff line number Diff line change
Expand Up @@ -449,17 +449,16 @@ int ddg_sccs_direct_connected(Graph *g, PlutoProg *prog, int scc1, int scc2) {
return 0;
}

/* Cut dependences between two SCCs
* Returns: number of dependences cut */
int cut_between_sccs(PlutoProg *prog, Graph *ddg, int scc1, int scc2) {
/// Cut dependences between two SCCs. Returns the number of dependences cut.
unsigned cut_between_sccs(PlutoProg *prog, Graph *ddg, int scc1, int scc2) {
Stmt **stmts = prog->stmts;
int nstmts = prog->nstmts;
PlutoContext *context = prog->context;

int nvar = prog->nvar;
int npar = prog->npar;

int i, j, num_satisfied;
int i, j;

if (!ddg_sccs_direct_connected(ddg, prog, scc1, scc2)) {
return 0;
Expand All @@ -480,7 +479,8 @@ int cut_between_sccs(PlutoProg *prog, Graph *ddg, int scc1, int scc2) {
stmts[i]->trans->val[stmts[i]->trans->nrows - 1][nvar + npar] = 1;
}
}
num_satisfied = dep_satisfaction_update(prog, stmts[0]->trans->nrows - 1);
unsigned num_satisfied =
dep_satisfaction_update(prog, stmts[0]->trans->nrows - 1);
if (num_satisfied >= 1) {
IF_DEBUG(
pluto_transformation_print_level(prog, prog->num_hyperplanes - 1););
Expand All @@ -495,11 +495,8 @@ int cut_between_sccs(PlutoProg *prog, Graph *ddg, int scc1, int scc2) {
return num_satisfied;
}

/*
* Cut dependences between all SCCs
*/
int cut_all_sccs(PlutoProg *prog, Graph *ddg) {
int i, j, num_satisfied;
/// Cut dependences between all SCCs. Return the number of dependences cut.
unsigned cut_all_sccs(PlutoProg *prog, Graph *ddg) {
Stmt **stmts = prog->stmts;
int nstmts = prog->nstmts;
int nvar = prog->nvar;
Expand All @@ -515,16 +512,17 @@ int cut_all_sccs(PlutoProg *prog, Graph *ddg) {

pluto_prog_add_hyperplane(prog, prog->num_hyperplanes, H_SCALAR);

for (i = 0; i < nstmts; i++) {
for (unsigned i = 0; i < nstmts; i++) {
pluto_stmt_add_hyperplane(stmts[i], H_SCALAR, stmts[i]->trans->nrows);
for (j = 0; j < nvar + npar; j++) {
for (unsigned j = 0; j < nvar + npar; j++) {
stmts[i]->trans->val[stmts[i]->trans->nrows - 1][j] = 0;
}
stmts[i]->trans->val[stmts[i]->trans->nrows - 1][nvar + npar] =
stmts[i]->scc_id;
}
IF_DEBUG(pluto_transformation_print_level(prog, prog->num_hyperplanes - 1););
num_satisfied = dep_satisfaction_update(prog, stmts[0]->trans->nrows - 1);
unsigned num_satisfied =
dep_satisfaction_update(prog, stmts[0]->trans->nrows - 1);
ddg_update(ddg, prog);

return num_satisfied;
Expand All @@ -540,8 +538,7 @@ int cut_all_sccs(PlutoProg *prog, Graph *ddg) {
* (Due to the algorithm used for computing SCCs, there are no edges
* between SCC<i> and SCC<j> where i > j)
*/
int cut_scc_dim_based(PlutoProg *prog, Graph *ddg) {
int i, j, k, count;
unsigned cut_scc_dim_based(PlutoProg *prog, Graph *ddg) {
Stmt **stmts = prog->stmts;
int nvar = prog->nvar;
int npar = prog->npar;
Expand All @@ -552,38 +549,37 @@ int cut_scc_dim_based(PlutoProg *prog, Graph *ddg) {

IF_DEBUG(printf("Cutting based on SCC dimensionalities\n"));

count = 0;

int cur_max_dim = ddg->sccs[0].max_dim;
unsigned cur_max_dim = ddg->sccs[0].max_dim;

pluto_prog_add_hyperplane(prog, prog->num_hyperplanes, H_SCALAR);

for (k = 0; k < ddg->num_sccs; k++) {
unsigned count = 0;
for (unsigned k = 0; k < ddg->num_sccs; k++) {
if (cur_max_dim != ddg->sccs[k].max_dim) {
cur_max_dim = ddg->sccs[k].max_dim;
count++;
}

for (i = 0; i < prog->nstmts; i++) {
for (unsigned i = 0; i < prog->nstmts; i++) {
if (stmts[i]->scc_id == k) {
pluto_stmt_add_hyperplane(stmts[i], H_SCALAR, stmts[i]->trans->nrows);
for (j = 0; j < nvar; j++) {
for (unsigned j = 0; j < nvar; j++) {
stmts[i]->trans->val[stmts[i]->trans->nrows - 1][j] = 0;
}
stmts[i]->trans->val[stmts[i]->trans->nrows - 1][nvar + npar] = count;
}
}
}

int num_new_carried =
unsigned num_new_carried =
dep_satisfaction_update(prog, stmts[0]->trans->nrows - 1);

if (num_new_carried >= 1) {
IF_DEBUG(
pluto_transformation_print_level(prog, prog->num_hyperplanes - 1););
ddg_update(ddg, prog);
} else {
for (i = 0; i < prog->nstmts; i++) {
for (unsigned i = 0; i < prog->nstmts; i++) {
stmts[i]->trans->nrows--;
}
prog->num_hyperplanes--;
Expand All @@ -592,7 +588,7 @@ int cut_scc_dim_based(PlutoProg *prog, Graph *ddg) {
return num_new_carried;
}

/* Heuristic cut */
/// Cuts dependences between statements using a heuristic.
void cut_smart(PlutoProg *prog, Graph *ddg) {
if (ddg->num_sccs == 0)
return;
Expand All @@ -603,29 +599,21 @@ void cut_smart(PlutoProg *prog, Graph *ddg) {
return;
}

int i, j;

int num_new_carried = 0;

/* First time, cut between SCCs of different dimensionalities */
if (cut_scc_dim_based(prog, ddg)) {
if (cut_scc_dim_based(prog, ddg))
return;
}

/* Cut in the center */
if (cut_between_sccs(prog, ddg, ceil(ddg->num_sccs / 2.0) - 1,
ceil(ddg->num_sccs / 2.0))) {
ceil(ddg->num_sccs / 2.0)))
return;
}

/* Cut between SCCs that are far away */
for (i = 0; i < ddg->num_sccs - 1; i++) {
for (j = ddg->num_sccs - 1; j >= i + 1; j--) {
for (unsigned i = 0; i < ddg->num_sccs - 1; i++) {
for (unsigned j = ddg->num_sccs - 1; j >= i + 1; j--) {
if ((int)prog->stmts[0]->trans->nrows <= 4 * prog->nvar + 2) {
if (ddg_sccs_direct_connected(ddg, prog, i, j)) {
// if (ddg->sccs[i].max_dim == ddg->sccs[j].max_dim) {
num_new_carried += cut_between_sccs(prog, ddg, i, j);
// }
cut_between_sccs(prog, ddg, i, j);
}
} else {
cut_all_sccs(prog, ddg);
Expand All @@ -635,10 +623,9 @@ void cut_smart(PlutoProg *prog, Graph *ddg) {
}
}

/* Distribute conservatively to maximize (rather random) fusion chance */
/// Distribute loop nests by cutting dependences in a conservative manner (fewer
/// dependences are cut).
void cut_conservative(PlutoProg *prog, Graph *ddg) {
int i, j;

if (cut_scc_dim_based(prog, ddg)) {
return;
}
Expand All @@ -650,8 +637,8 @@ void cut_conservative(PlutoProg *prog, Graph *ddg) {
}

/* Cut between SCCs that are far away */
for (i = 0; i < ddg->num_sccs - 1; i++) {
for (j = ddg->num_sccs - 1; j >= i + 1; j--) {
for (unsigned i = 0; i < ddg->num_sccs - 1; i++) {
for (unsigned j = ddg->num_sccs - 1; j >= i + 1; j--) {
if ((int)prog->stmts[0]->trans->nrows <= 4 * prog->nvar + 2) {
if (cut_between_sccs(prog, ddg, i, j)) {
return;
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4 changes: 2 additions & 2 deletions lib/pluto.h
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Original file line number Diff line number Diff line change
Expand Up @@ -549,8 +549,8 @@ void ddg_compute_scc(PlutoProg *prog);
void ddg_compute_cc(PlutoProg *prog);
Graph *ddg_create(PlutoProg *prog);
int ddg_sccs_direct_connected(Graph *g, PlutoProg *prog, int scc1, int scc2);
int cut_between_sccs(PlutoProg *prog, Graph *ddg, int scc1, int scc2);
int cut_all_sccs(PlutoProg *prog, Graph *ddg);
unsigned cut_between_sccs(PlutoProg *prog, Graph *ddg, int scc1, int scc2);
unsigned cut_all_sccs(PlutoProg *prog, Graph *ddg);
void cut_smart(PlutoProg *prog, Graph *ddg);

void pluto_print_dep_directions(PlutoProg *prog);
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