diff --git a/tslang/lib/TypeScript/MLIRGenImpl.h b/tslang/lib/TypeScript/MLIRGenImpl.h
index 1f55d5c62..c1b71b94e 100644
--- a/tslang/lib/TypeScript/MLIRGenImpl.h
+++ b/tslang/lib/TypeScript/MLIRGenImpl.h
@@ -9645,7 +9645,8 @@ class MLIRGenImpl
         {
         //case 8:
         //case 16:
-        case 32:
+        // a literal in [2^31, 2^32) does not fit s32; it takes s64 (default branch), not u32,
+        // so arithmetic with other integer literals does not wrap
         case 64:
         case 128:
             unsignedVal = true;
diff --git a/tslang/test/tester/CMakeLists.txt b/tslang/test/tester/CMakeLists.txt
index d8ae1e3f8..81abd0a6d 100644
--- a/tslang/test/tester/CMakeLists.txt
+++ b/tslang/test/tester/CMakeLists.txt
@@ -273,6 +273,7 @@ tslang_add_test(NAME test-compile-00-equals COMMAND test-runner "${PROJECT_SOURC
 tslang_add_test(NAME test-compile-00-bool-arith-ops COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00bool_arith_ops.ts")
 tslang_add_test(NAME test-compile-00-int64-shift-bitwise COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00int64_shift_bitwise.ts")
 tslang_add_test(NAME test-compile-00-int64-mul-literal COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00int64_mul_literal.ts")
+tslang_add_test(NAME test-compile-00-int-literal-above-s32 COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00int_literal_above_s32.ts")
 tslang_add_test(NAME test-compile-00-literal-union-arith COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00literal_union_arith.ts")
 tslang_add_test(NAME test-compile-00-literal-union-cast COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00literal_union_cast.ts")
 tslang_add_test(NAME test-compile-00-bool-const-array COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00bool_const_array.ts")
@@ -826,6 +827,7 @@ tslang_add_test(NAME test-jit-00-equals COMMAND test-runner -jit "${PROJECT_SOUR
 tslang_add_test(NAME test-jit-00-bool-arith-ops COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00bool_arith_ops.ts")
 tslang_add_test(NAME test-jit-00-int64-shift-bitwise COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00int64_shift_bitwise.ts")
 tslang_add_test(NAME test-jit-00-int64-mul-literal COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00int64_mul_literal.ts")
+tslang_add_test(NAME test-jit-00-int-literal-above-s32 COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00int_literal_above_s32.ts")
 tslang_add_test(NAME test-jit-00-literal-union-arith COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00literal_union_arith.ts")
 tslang_add_test(NAME test-jit-00-literal-union-cast COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00literal_union_cast.ts")
 tslang_add_test(NAME test-jit-00-bool-const-array COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00bool_const_array.ts")
@@ -1836,6 +1838,7 @@ set(TSLANG_CORPUS
     00bool_arith_ops.ts
     00int64_shift_bitwise.ts
     00int64_mul_literal.ts
+    00int_literal_above_s32.ts
     00literal_union_arith.ts
     00literal_union_cast.ts
     00bool_const_array.ts
diff --git a/tslang/test/tester/tests/00int_literal_above_s32.ts b/tslang/test/tester/tests/00int_literal_above_s32.ts
new file mode 100644
index 000000000..23fca0e6b
--- /dev/null
+++ b/tslang/test/tester/tests/00int_literal_above_s32.ts
@@ -0,0 +1,45 @@
+// regression test: an integer literal that does not fit s32 gets a 64-bit type.
+//
+// bug found and fixed: a literal in [2^31, 2^32) (3000000000, 2147483648, 0xFFFFFFFF) was typed u32,
+// so arithmetic with other integer literals was done in 32 bits: `1 + 3000000000` printed
+// -1294967295. Such a literal is now s64, like 5000000000 already was; smaller literals stay s32.
+
+function main() {
+    const x = 3000000000;
+    print(x);
+    assert(`${x}` == "3000000000", "const");
+
+    const sum = 1 + 3000000000;
+    print(sum);
+    assert(`${sum}` == "3000000001", "1 + 3000000000");
+
+    const twice = 3000000000 * 2;
+    assert(`${twice}` == "6000000000", "3000000000 * 2");
+
+    let z = 3000000000;
+    z += 3000000000;
+    assert(`${z}` == "6000000000", "z += 3000000000");
+
+    const allOnes = 0xFFFFFFFF + 1;
+    assert(`${allOnes}` == "4294967296", "0xFFFFFFFF + 1");
+
+    const belowMin = -2147483649;
+    assert(`${belowMin}` == "-2147483649", "-2147483649");
+
+    const minPlus = 2147483648 + 1;
+    assert(`${minPlus}` == "2147483649", "2147483648 + 1");
+
+    // a literal that fits s32 is still s32
+    const small = 2147483647;
+    assert(`${small}` == "2147483647", "s32 max");
+
+    // narrowing into a declared 32-bit type still works
+    const m: s32 = -2147483648;
+    assert(`${m}` == "-2147483648", "s32 min");
+    const u: u32 = 0xFFFFFFFF;
+    assert(`${u}` == "4294967295", "u32 max");
+    const v: u32 = 3000000000;
+    assert(`${v}` == "3000000000", "u32 3000000000");
+
+    print("done.");
+}
diff --git a/tslang/test/tester/tests/02numbers.ts b/tslang/test/tester/tests/02numbers.ts
index a646254e4..0d9fdd5d3 100644
--- a/tslang/test/tester/tests/02numbers.ts
+++ b/tslang/test/tester/tests/02numbers.ts
@@ -139,7 +139,8 @@ function testNums(): void {
     testRightU(0x30000004, 0, 0x30000004)
     testLeft(1, 29, 0x20000000)
     testLeft(1, 30, 0x40000000)
-    testLeft(1, 31, 0x80000000 >> 0)
+    // 0x80000000 is an s64 literal, so `0x80000000 >> 0` no longer narrows it to 32 bits
+    testLeft(1, 31, -2147483648)
     //testLeft(1, 32, 1);
 
     tt = 2;