diff --git a/tests/fixtures/unsigned_calcs.c b/tests/fixtures/unsigned_calcs.c
new file mode 100644
index 0000000..89b1735
--- /dev/null
+++ b/tests/fixtures/unsigned_calcs.c
@@ -0,0 +1,25 @@
+#include <stdio.h>
+
+long foo(unsigned);
+long foo(unsigned int a) { return a; }
+
+int main() {
+  printf("%ld\n", foo((unsigned short)-1));
+
+  unsigned int c = 2147483649;
+  int d = 2000;
+  int s = d + c;
+  printf("%d\n", c);
+  printf("%d\n", s);
+
+  unsigned long i = 999999u * 9999999 * 999999;
+  unsigned long l = -9223372036854775808u + 1;
+  printf("%lu\n", i);
+  printf("%lu\n", l);
+
+  int eq = 18446744073709551615u == 18446744073709551615ll;
+  printf("%d\n", eq);
+
+  unsigned char n = 372897938;
+  printf("%ld\n", (long)n);
+}
diff --git a/tests/snapshots/success_unsigned_calcs b/tests/snapshots/success_unsigned_calcs
new file mode 100644
index 0000000..8f74c1c
--- /dev/null
+++ b/tests/snapshots/success_unsigned_calcs
@@ -0,0 +1,7 @@
+65535
+-2147483647
+-2147481647
+420793087
+9223372036854775809
+1
+146
diff --git a/wrecc_compiler/src/compiler/codegen/mod.rs b/wrecc_compiler/src/compiler/codegen/mod.rs
index 98ee26c..67a9125 100644
--- a/wrecc_compiler/src/compiler/codegen/mod.rs
+++ b/wrecc_compiler/src/compiler/codegen/mod.rs
@@ -1023,6 +1023,16 @@ impl Compiler {
                 if value_reg.get_type().size() < 4 {
                     self.write_out(Lir::Movz(value_reg.clone(), dest_reg.clone()));
                 } else {
+                    // convert registers since otherwise will read memory that isnt
+                    // that doesnt belong to value_reg: casting unsigned int to long
+                    // int a: -4(%rbp), 4 bytes allocate
+                    // `movq -4(%rbp), %r10`, would read 8 bytes
+                    value_reg = convert_reg!(
+                        self,
+                        value_reg,
+                        Register::Temp(..) | Register::Stack(..) | Register::Label(..)
+                    );
+
                     value_reg.set_type(new_type);
                     self.write_out(Lir::Mov(value_reg.clone(), dest_reg.clone()))
                 }
diff --git a/wrecc_compiler/src/compiler/typechecker/fold.rs b/wrecc_compiler/src/compiler/typechecker/fold.rs
index 17fc2a0..b5d9e39 100644
--- a/wrecc_compiler/src/compiler/typechecker/fold.rs
+++ b/wrecc_compiler/src/compiler/typechecker/fold.rs
@@ -722,6 +722,7 @@ mod tests {
             "(unsigned)420793087",
             "unsigned int",
         );
+        assert_fold_type("999999u * 9999999 * 999999", "420793087u", "unsigned int");
         assert_fold_error!(
             "999999 * 9999999 * 999999",
             ErrorKind::IntegerOverflow(QualType {
@@ -787,5 +788,6 @@ mod tests {
         assert_fold("(short *)1 + -5", "(short*)-9");
         assert_fold("(int*)1 + -9223372036854775807", "(int*)5");
         assert_fold_error!("(int*)1 + -9223372036854775808", ErrorKind::ScaleOverflow);
+        assert_fold_error!("(int*)1 - 9223372036854775809ul", ErrorKind::ScaleOverflow);
     }
 }
diff --git a/wrecc_compiler/src/compiler/typechecker/mod.rs b/wrecc_compiler/src/compiler/typechecker/mod.rs
index 856f358..a0d4b86 100644
--- a/wrecc_compiler/src/compiler/typechecker/mod.rs
+++ b/wrecc_compiler/src/compiler/typechecker/mod.rs
@@ -2614,6 +2614,8 @@ mod tests {
         assert_type!("(void*)1 == a", "int", "long* a;");
         assert_type!("0 == a", "int", "long* a;");
         assert_type!("a == 0", "int", "int* a;");
+        assert_type!("a == 2l", "int", "unsigned int a;");
+        assert_type!("a == 2lu", "int", "int a;");
 
         assert_type_err!("1 == a", ErrorKind::InvalidComp(..), "long *a;");
         assert_type_err!("a == b", ErrorKind::InvalidComp(..), "int *a; long *b;");