From 31b00b4c72f89cf7e9e61733141838cf7819f2db Mon Sep 17 00:00:00 2001
From: KrystalDelusion <93062060+KrystalDelusion@users.noreply.github.com>
Date: Fri, 31 Jan 2025 11:03:33 +1300
Subject: [PATCH] celledges: Use b_width_capped for left shifts

`b_width_capped` already exists for preventing arithmetic overflow, limiting the value of `b_width` to 30.  This just changes the left shifts to also use it.
The caveat of incorrect results for extremely large values of `a_width` still applies, as does the improbability of that actually happening.
This fixes #4844 (or at least, the floating point exception; the circuit still isn't valid but I think that's fine).
---
 kernel/celledges.cc | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/celledges.cc b/kernel/celledges.cc
index bad7124d9..68e55db02 100644
--- a/kernel/celledges.cc
+++ b/kernel/celledges.cc
@@ -253,13 +253,13 @@ void shift_op(AbstractCellEdgesDatabase *db, RTLIL::Cell *cell)
 				if (a_width == 1 && is_signed) {
 					int skip = 1 << (k + 1);
 					int base = skip -1;
-					if (i % skip != base && i - a_width + 2 < 1 << b_width)
+					if (i % skip != base && i - a_width + 2 < 1 << b_width_capped)
 						db->add_edge(cell, ID::B, k, ID::Y, i, -1);	
 				} else if (is_signed) {
-					if (i - a_width + 2 < 1 << b_width)
+					if (i - a_width + 2 < 1 << b_width_capped)
 						db->add_edge(cell, ID::B, k, ID::Y, i, -1);
 				} else {
-					if (i - a_width + 1 < 1 << b_width)
+					if (i - a_width + 1 < 1 << b_width_capped)
 						db->add_edge(cell, ID::B, k, ID::Y, i, -1);
 				}
 			// right shifts