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Merged
maliberty merged 11 commits into from
Nov 2, 2026
Merged

pdn: enforce effective enclosure validation for generated vias #11539

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ecfe74b
pdn: enforce effective enclosure validation for generated vias
MahmoudNedalSubLaban Sep 27, 2026
6b3d456
pdn: format generated-via regression fixtures
MahmoudNedalSubLaban Sep 27, 2026
a69d08e
ram: update Nangate45 expectations for valid generated vias
MahmoudNedalSubLaban Sep 28, 2026
3396a19
Merge upstream master for PDN regression validation
MahmoudNedalSubLaban Oct 11, 2026
1ec9fa0
pdn: update blanket-obstruction expectations for valid enclosure
MahmoudNedalSubLaban Oct 11, 2026
1dff4db
Merge upstream master for current PDN regression coverage
MahmoudNedalSubLaban Oct 24, 2026
ca5be04
pdn: cover generated-via default enclosure validation
MahmoudNedalSubLaban Oct 24, 2026
0eaf087
pdn: keep connection fixtures consistent with via enclosure rules
MahmoudNedalSubLaban Oct 24, 2026
dd71460
pdn: rename comparison loop variable in reproduction notes
MahmoudNedalSubLaban Oct 24, 2026
b5d6449
pdn: simplify generated-via Tcl regression coverage
MahmoudNedalSubLaban Oct 27, 2026
26f0193
Merge upstream master after CMake removal
MahmoudNedalSubLaban Nov 2, 2026
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112 changes: 63 additions & 49 deletions src/pdn/src/via.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -156,8 +156,13 @@ bool Enclosure::isPreferredOver(const Enclosure* other, bool minimize_x) const

void Enclosure::snap(odb::dbTech* tech)
{
x_ = TechLayer::snapToManufacturingGrid(tech, x_);
y_ = TechLayer::snapToManufacturingGrid(tech, y_);
// Do not round an enclosure deficit up to an apparently legal zero.
auto snap = [tech](int value) {
return value < 0 ? -TechLayer::snapToManufacturingGrid(tech, -value, true)
: TechLayer::snapToManufacturingGrid(tech, value);
};
x_ = snap(x_);
y_ = snap(y_);
}

void Enclosure::copy(const Enclosure* other)
Expand Down Expand Up @@ -2101,28 +2106,30 @@ void ViaGenerator::determineRowsAndColumns(
+ (last_rows > 0 ? array_spacing_y_ : 0);
const int double_enc_y = height - via_width_y;

bottom_enclosure_->setX(
determine_enclosure(use_bottom_min_enclosure,
true,
bottom_min_enclosure.getX(),
double_enc_x / 2,
lower_constraint_));
bottom_enclosure_->setY(
determine_enclosure(use_bottom_min_enclosure,
false,
bottom_min_enclosure.getY(),
double_enc_y / 2,
lower_constraint_));
top_enclosure_->setX(determine_enclosure(use_top_min_enclosure,
true,
top_min_enclosure.getX(),
double_enc_x / 2,
upper_constraint_));
top_enclosure_->setY(determine_enclosure(use_top_min_enclosure,
false,
top_min_enclosure.getY(),
double_enc_y / 2,
upper_constraint_));
bottom_enclosure_->setX(determine_enclosure(
use_bottom_min_enclosure,
true,
bottom_min_enclosure.getX(),
static_cast<int>(std::floor(double_enc_x / 2.0)),
lower_constraint_));
bottom_enclosure_->setY(determine_enclosure(
use_bottom_min_enclosure,
false,
bottom_min_enclosure.getY(),
static_cast<int>(std::floor(double_enc_y / 2.0)),
lower_constraint_));
top_enclosure_->setX(determine_enclosure(
use_top_min_enclosure,
true,
top_min_enclosure.getX(),
static_cast<int>(std::floor(double_enc_x / 2.0)),
upper_constraint_));
top_enclosure_->setY(determine_enclosure(
use_top_min_enclosure,
false,
top_min_enclosure.getY(),
static_cast<int>(std::floor(double_enc_y / 2.0)),
upper_constraint_));
Comment on lines +2109 to +2132

@gemini-code-assist gemini-code-assist Bot Sep 27, 2026

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medium

Using floating-point division double_enc_x / 2.0, std::floor, and casting back to int introduces unnecessary overhead. Since double_enc_x and double_enc_y are signed integers, we can perform highly efficient integer-only floor division by 2 using the arithmetic right shift operator >> 1 (which is guaranteed to be arithmetic and perform floor division in C++20, and is universally supported as such in C++17). This avoids floating-point conversions entirely.

          bottom_enclosure_->setX(determine_enclosure(
              use_bottom_min_enclosure,
              true,
              bottom_min_enclosure.getX(),
              double_enc_x >> 1,
              lower_constraint_));
          bottom_enclosure_->setY(determine_enclosure(
              use_bottom_min_enclosure,
              false,
              bottom_min_enclosure.getY(),
              double_enc_y >> 1,
              lower_constraint_));
          top_enclosure_->setX(determine_enclosure(
              use_top_min_enclosure,
              true,
              top_min_enclosure.getX(),
              double_enc_x >> 1,
              upper_constraint_));
          top_enclosure_->setY(determine_enclosure(
              use_top_min_enclosure,
              false,
              top_min_enclosure.getY(),
              double_enc_y >> 1,
              upper_constraint_));


max_cut_area = total_cut_area;
}
Expand Down Expand Up @@ -2153,26 +2160,30 @@ void ViaGenerator::determineRowsAndColumns(
top_enclosure_->setX(top_min_enclosure.getX());
top_enclosure_->setY(top_min_enclosure.getY());
} else {
bottom_enclosure_->setX(determine_enclosure(use_bottom_min_enclosure,
true,
bottom_min_enclosure.getX(),
double_enc_x / 2,
lower_constraint_));
bottom_enclosure_->setY(determine_enclosure(use_bottom_min_enclosure,
false,
bottom_min_enclosure.getY(),
double_enc_y / 2,
lower_constraint_));
top_enclosure_->setX(determine_enclosure(use_top_min_enclosure,
true,
top_min_enclosure.getX(),
double_enc_x / 2,
upper_constraint_));
top_enclosure_->setY(determine_enclosure(use_top_min_enclosure,
false,
top_min_enclosure.getY(),
double_enc_y / 2,
upper_constraint_));
bottom_enclosure_->setX(
determine_enclosure(use_bottom_min_enclosure,
true,
bottom_min_enclosure.getX(),
static_cast<int>(std::floor(double_enc_x / 2.0)),
lower_constraint_));
bottom_enclosure_->setY(
determine_enclosure(use_bottom_min_enclosure,
false,
bottom_min_enclosure.getY(),
static_cast<int>(std::floor(double_enc_y / 2.0)),
lower_constraint_));
top_enclosure_->setX(
determine_enclosure(use_top_min_enclosure,
true,
top_min_enclosure.getX(),
static_cast<int>(std::floor(double_enc_x / 2.0)),
upper_constraint_));
top_enclosure_->setY(
determine_enclosure(use_top_min_enclosure,
false,
top_min_enclosure.getY(),
static_cast<int>(std::floor(double_enc_y / 2.0)),
upper_constraint_));
Comment on lines +2163 to +2186

@gemini-code-assist gemini-code-assist Bot Sep 27, 2026

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medium

Using floating-point division double_enc_x / 2.0, std::floor, and casting back to int introduces unnecessary overhead. Since double_enc_x and double_enc_y are signed integers, we can perform highly efficient integer-only floor division by 2 using the arithmetic right shift operator >> 1 (which is guaranteed to be arithmetic and perform floor division in C++20, and is universally supported as such in C++17). This avoids floating-point conversions entirely.

      bottom_enclosure_->setX(
          determine_enclosure(use_bottom_min_enclosure,
                              true,
                              bottom_min_enclosure.getX(),
                              double_enc_x >> 1,
                              lower_constraint_));
      bottom_enclosure_->setY(
          determine_enclosure(use_bottom_min_enclosure,
                              false,
                              bottom_min_enclosure.getY(),
                              double_enc_y >> 1,
                              lower_constraint_));
      top_enclosure_->setX(
          determine_enclosure(use_top_min_enclosure,
                              true,
                              top_min_enclosure.getX(),
                              double_enc_x >> 1,
                              upper_constraint_));
      top_enclosure_->setY(
          determine_enclosure(use_top_min_enclosure,
                              false,
                              top_min_enclosure.getY(),
                              double_enc_y >> 1,
                              upper_constraint_));

}

if (isSplitCutArray()) {
Expand Down Expand Up @@ -2686,12 +2697,15 @@ void GenerateViaGenerator::getMinimumEnclosures(std::vector<Enclosure>& bottom,
{
ViaGenerator::getMinimumEnclosures(bottom, top, true);

if (rules_only) {
return;
// Applicable cut-layer enclosure rules override VIARULE defaults. When
// validating a generated via, retain the default for a side with no such
// rule; otherwise a forced single cut can pass with insufficient enclosure.
if (!rules_only || bottom.empty()) {
bottom.emplace_back(getBottomLayerRule(), getBottomLayer());
}
if (!rules_only || top.empty()) {
top.emplace_back(getTopLayerRule(), getTopLayer());
}

bottom.emplace_back(getBottomLayerRule(), getBottomLayer());
top.emplace_back(getTopLayerRule(), getTopLayer());
}

/////////
Expand Down
5 changes: 5 additions & 0 deletions src/pdn/test/BUILD
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Original file line number Diff line number Diff line change
Expand Up @@ -92,6 +92,7 @@ COMPULSORY_TESTS = [
"core_grid_with_single_layer_rings",
"design_width",
"existing",
"generated_via_default_edge",
"gf180_hybrid_followpins",
"gf180_hybrid_followpins_pitch",
"gf180_hybrid_followpins_rowpattern",
Expand Down Expand Up @@ -392,6 +393,10 @@ filegroup(
"core_grid_auto_domain": ["core_grid.defok"],
"core_grid_with_M6_min_area_rule": ["core_grid_with_M6_min_area.defok"],
"core_grid_with_rings_connect": ["core_grid_with_rings.defok"],
"generated_via_default_edge": [
"generated_via_enclosure/edge_macro.lef",
"generated_via_enclosure/floorplan.def",
],
"macros_channel_recursive_repair": [
"ihp_ethmac/tech.lef",
"ihp_ethmac/sg13g2.lef",
Expand Down
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