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HeAP: support for bel region constraints

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Signed-off-by: David Shah <dave@ds0.me>
This commit is contained in:
David Shah 2019-11-26 10:01:33 +00:00
parent 08cf545d9b
commit 75f403db60
1 changed files with 83 additions and 6 deletions
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89
common/placer_heap.cc
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@ -308,6 +308,14 @@ class HeAPPlacer
std::vector<std::vector<int>> nearest_row_with_bel;
std::vector<std::vector<int>> nearest_col_with_bel;
struct BoundingBox
{
// Actual bounding box
int x0 = 0, x1 = 0, y0 = 0, y1 = 0;
};
std::unordered_map<IdString, BoundingBox> constraint_region_bounds;
// In some cases, we can't use bindBel because we allow overlap in the earlier stages. So we use this custom
// structure instead
struct CellLocation
@ -443,6 +451,31 @@ class HeAPPlacer
nr.at(y) = loc.y;
}
}
// Determine bounding boxes of region constraints
for (auto &region : sorted(ctx->region)) {
Region *r = region.second;
BoundingBox bb;
if (r->constr_bels) {
bb.x0 = std::numeric_limits<int>::max();
bb.x1 = std::numeric_limits<int>::min();
bb.y0 = std::numeric_limits<int>::max();
bb.y1 = std::numeric_limits<int>::min();
for (auto bel : r->bels) {
Loc loc = ctx->getBelLocation(bel);
bb.x0 = std::min(bb.x0, loc.x);
bb.x1 = std::max(bb.x1, loc.x);
bb.y0 = std::min(bb.y0, loc.y);
bb.y1 = std::max(bb.y1, loc.y);
}
} else {
bb.x0 = 0;
bb.y0 = 0;
bb.x1 = max_x;
bb.y1 = max_y;
}
constraint_region_bounds[r->name] = bb;
}
}
// Build and solve in one direction
@ -684,9 +717,15 @@ class HeAPPlacer
if (yaxis) {
cell_locs.at(solve_cells.at(i)->name).rawy = vals.at(i);
cell_locs.at(solve_cells.at(i)->name).y = std::min(max_y, std::max(0, int(vals.at(i))));
if (solve_cells.at(i)->region != nullptr)
cell_locs.at(solve_cells.at(i)->name).y =
limit_to_reg(solve_cells.at(i)->region, cell_locs.at(solve_cells.at(i)->name).y, true);
} else {
cell_locs.at(solve_cells.at(i)->name).rawx = vals.at(i);
cell_locs.at(solve_cells.at(i)->name).x = std::min(max_x, std::max(0, int(vals.at(i))));
if (solve_cells.at(i)->region != nullptr)
cell_locs.at(solve_cells.at(i)->name).x =
limit_to_reg(solve_cells.at(i)->region, cell_locs.at(solve_cells.at(i)->name).x, false);
}
}
@ -761,8 +800,21 @@ class HeAPPlacer
while (!placed) {
int nx = ctx->rng(2 * radius + 1) + std::max(cell_locs.at(ci->name).x - radius, 0);
int ny = ctx->rng(2 * radius + 1) + std::max(cell_locs.at(ci->name).y - radius, 0);
int rx = radius, ry = radius;
if (ci->region != nullptr) {
rx = std::min(radius, (constraint_region_bounds[ci->region->name].x1 -
constraint_region_bounds[ci->region->name].x0) /
2 +
1);
ry = std::min(radius, (constraint_region_bounds[ci->region->name].y1 -
constraint_region_bounds[ci->region->name].y0) /
2 +
1);
}
int nx = ctx->rng(2 * rx + 1) + std::max(cell_locs.at(ci->name).x - rx, 0);
int ny = ctx->rng(2 * ry + 1) + std::max(cell_locs.at(ci->name).y - ry, 0);
iter++;
iter_at_radius++;
@ -820,6 +872,8 @@ class HeAPPlacer
if (ci->constr_children.empty() && !ci->constr_abs_z) {
for (auto sz : fb.at(nx).at(ny)) {
if (ci->region != nullptr && ci->region->constr_bels && !ci->region->bels.count(sz))
continue;
if (ctx->checkBelAvail(sz) || (radius > ripup_radius || ctx->rng(20000) < 10)) {
CellInfo *bound = ctx->getBoundBelCell(sz);
if (bound != nullptr) {
@ -881,6 +935,8 @@ class HeAPPlacer
Loc ploc = visit.front().second;
visit.pop();
BelId target = ctx->getBelByLocation(ploc);
if (vc->region != nullptr && vc->region->constr_bels && !vc->region->bels.count(target))
continue;
CellInfo *bound;
if (target == BelId() || ctx->getBelType(target) != vc->type)
goto fail;
@ -948,6 +1004,15 @@ class HeAPPlacer
// Implementation of the cut-based spreading as described in the HeAP/SimPL papers
static constexpr float beta = 0.9;
template <typename T> T limit_to_reg(Region *reg, T val, bool dir)
{
if (reg == nullptr)
return val;
int limit_low = dir ? constraint_region_bounds[reg->name].y0 : constraint_region_bounds[reg->name].x0;
int limit_high = dir ? constraint_region_bounds[reg->name].y1 : constraint_region_bounds[reg->name].x1;
return std::max<T>(std::min<T>(val, limit_high), limit_low);
}
struct ChainExtent
{
int x0, y0, x1, y1;
@ -1460,10 +1525,22 @@ class HeAPPlacer
: p->cell_locs.at(cut_cells.at(br.first - 1)->name).rawx;
double m = (br.second - bl.second) / std::max(0.00001, orig_right - orig_left);
for (int j = bl.first; j < br.first; j++) {
auto &pos = dir ? p->cell_locs.at(cut_cells.at(j)->name).rawy
: p->cell_locs.at(cut_cells.at(j)->name).rawx;
NPNR_ASSERT(pos >= orig_left && pos <= orig_right);
pos = bl.second + m * (pos - orig_left);
Region *cr = cut_cells.at(j)->region;
if (cr != nullptr) {
// Limit spreading bounds to constraint region; if applicable
double brsc = p->limit_to_reg(cr, br.second, dir);
double blsc = p->limit_to_reg(cr, bl.second, dir);
double mr = (brsc - blsc) / std::max(0.00001, orig_right - orig_left);
auto &pos = dir ? p->cell_locs.at(cut_cells.at(j)->name).rawy
: p->cell_locs.at(cut_cells.at(j)->name).rawx;
NPNR_ASSERT(pos >= orig_left && pos <= orig_right);
pos = blsc + mr * (pos - orig_left);
} else {
auto &pos = dir ? p->cell_locs.at(cut_cells.at(j)->name).rawy
: p->cell_locs.at(cut_cells.at(j)->name).rawx;
NPNR_ASSERT(pos >= orig_left && pos <= orig_right);
pos = bl.second + m * (pos - orig_left);
}
// log("[%f, %f] -> [%f, %f]: %f -> %f\n", orig_left, orig_right, bl.second, br.second,
// orig_pos, pos);
}