From 4f0e0339b112b459da784f80a8f4ea387ec29286 Mon Sep 17 00:00:00 2001
From: Edd Barrett <vext01@gmail.com>
Date: Wed, 20 Dec 2023 11:44:01 +0000
Subject: [PATCH] Kill pow().

---
 ykrt/src/compile/jitc_yk/jit_ir.rs | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/ykrt/src/compile/jitc_yk/jit_ir.rs b/ykrt/src/compile/jitc_yk/jit_ir.rs
index 65e402302..82215cf23 100644
--- a/ykrt/src/compile/jitc_yk/jit_ir.rs
+++ b/ykrt/src/compile/jitc_yk/jit_ir.rs
@@ -89,7 +89,8 @@ pub enum Operand {
 
 impl Operand {
     pub(crate) fn new(kind: OpKind, val: u64) -> Self {
-        if val < 2u64.pow(u32::try_from(SHORT_OPERAND_VALUE_SIZE).unwrap()) {
+        // check if the operand's value can fit in a short operand.
+        if val & (u64::MAX << SHORT_OPERAND_VALUE_SIZE) == 0 {
             Self::Short(ShortOperand::new(kind, val))
         } else {
             todo!()
@@ -418,4 +419,17 @@ mod tests {
         debug_assert_eq!(inst.operand(1), Operand::Short(ShortOperand(0)));
         debug_assert_eq!(inst.operand(2), Operand::Short(ShortOperand(0x3ffff)));
     }
+
+    #[test]
+    fn does_fit_short_operand() {
+        for i in 0..SHORT_OPERAND_VALUE_SIZE {
+            Operand::new(OpKind::Local, 1 << i);
+        }
+    }
+
+    #[test]
+    #[should_panic]
+    fn doesnt_fit_short_operand() {
+        Operand::new(OpKind::Local, 1 << SHORT_OPERAND_VALUE_SIZE);
+    }
 }