From 132b18e2b39feca3b90b1b13df2b4649b1661fd5 Mon Sep 17 00:00:00 2001
From: leesongun <12179851+leesongun@users.noreply.github.com>
Date: Tue, 13 Jul 2021 16:16:57 +0900
Subject: [PATCH] Fix bigint_shl (#9305)

---
 src/stage1/bigint.cpp  | 2 +-
 test/behavior/eval.zig | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/stage1/bigint.cpp b/src/stage1/bigint.cpp
index 45c3a96623..3ab6d08d79 100644
--- a/src/stage1/bigint.cpp
+++ b/src/stage1/bigint.cpp
@@ -1352,7 +1352,7 @@ void bigint_shl(BigInt *dest, const BigInt *op1, const BigInt *op2) {
 
     if (op1->digit_count == 1 && shift_amt < 64) {
         dest->data.digit = op1_digits[0] << shift_amt;
-        if (dest->data.digit > op1_digits[0]) {
+        if (dest->data.digit >> shift_amt == op1_digits[0]) {
             dest->digit_count = 1;
             dest->is_negative = op1->is_negative;
             return;
diff --git a/test/behavior/eval.zig b/test/behavior/eval.zig
index 80a3bccb7c..566ed74e2d 100644
--- a/test/behavior/eval.zig
+++ b/test/behavior/eval.zig
@@ -573,6 +573,13 @@ test "comptime shlWithOverflow" {
     try expect(ct_shifted == rt_shifted);
 }
 
+test "comptime shl" {
+    var a: u128 = 3;
+    var b: u7 = 63;
+    var c: u128 = 3 << 63;
+    try expectEqual(a << b, c);
+}
+
 test "runtime 128 bit integer division" {
     var a: u128 = 152313999999999991610955792383;
     var b: u128 = 10000000000000000000;