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Merge pull request #5066 from YosysHQ/george/opt_expr_shr_sign

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opt_expr: fix sign extension for shifts
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KrystalDelusion 2025-04-29 09:29:10 +12:00 • committed by GitHub
commit bfe05965f9
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3 changed files with 58 additions and 7 deletions
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6
kernel/celledges.cc
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@ -247,7 +247,7 @@ void shift_op(AbstractCellEdgesDatabase *db, RTLIL::Cell *cell)
db->add_edge(cell, ID::A, a_width - 1, ID::Y, i, -1);
}
for (int k = 0; k < b_width; k++) {
for (int k = 0; k < b_width_capped; k++) {
// left shifts
if (cell->type.in(ID($shl), ID($sshl))) {
if (a_width == 1 && is_signed) {
@ -268,7 +268,7 @@ void shift_op(AbstractCellEdgesDatabase *db, RTLIL::Cell *cell)
bool shift_in_bulk = i < a_width - 1;
// can we jump into the zero-padding by toggling B[k]?
bool zpad_jump = (((y_width - i) & ((1 << (k + 1)) - 1)) != 0 \
&& (((y_width - i) & ~(1 << k)) < (1 << b_width)));
&& (((y_width - i) & ~(1 << k)) < (1 << b_width_capped)));
if (shift_in_bulk || (cell->type.in(ID($shr), ID($shift), ID($shiftx)) && zpad_jump))
db->add_edge(cell, ID::B, k, ID::Y, i, -1);
@ -279,7 +279,7 @@ void shift_op(AbstractCellEdgesDatabase *db, RTLIL::Cell *cell)
// bidirectional shifts (positive B shifts right, negative left)
} else if (cell->type.in(ID($shift), ID($shiftx)) && is_b_signed) {
if (is_signed) {
if (k != b_width - 1) {
if (k != b_width_capped - 1) {
bool r_shift_in_bulk = i < a_width - 1;
// assuming B is positive, can we jump into the upper zero-padding by toggling B[k]?
bool r_zpad_jump = (((y_width - i) & ((1 << (k + 1)) - 1)) != 0 \