need unsigned comparison when checking shift widths for overflow in functional backend

aiju · aiju · commit e36eaa544549 · 2024-06-12T12:28:09.000+01:00
diff --git a/kernel/graphtools.h b/kernel/graphtools.h
@@ -40,7 +40,7 @@ class CellSimplifier {
 		} else {
 			reduced_b_width = new_width;
 			T lower_b = factory.slice(b, b_width, 0, new_width);
-			T overflow = factory.gt(b, factory.constant(RTLIL::Const(y_width, b_width)), b_width);
+			T overflow = factory.ugt(b, factory.constant(RTLIL::Const(y_width, b_width)), b_width);
 			return factory.mux(lower_b, factory.constant(RTLIL::Const(y_width, new_width)), overflow, new_width);
 		}
 	}

Original file line number	Diff line number	Diff line change
`@@ -40,7 +40,7 @@ class CellSimplifier {`
`40`	`40`	`} else {`
`41`	`41`	`reduced_b_width = new_width;`
`42`	`42`	`T lower_b = factory.slice(b, b_width, 0, new_width);`
`43`		`- T overflow = factory.gt(b, factory.constant(RTLIL::Const(y_width, b_width)), b_width);`
	`43`	`+ T overflow = factory.ugt(b, factory.constant(RTLIL::Const(y_width, b_width)), b_width);`
`44`	`44`	`return factory.mux(lower_b, factory.constant(RTLIL::Const(y_width, new_width)), overflow, new_width);`
`45`	`45`	`}`
`46`	`46`	`}`