From 3b1a2279134cca08757e66d826f2f8a6d6512289 Mon Sep 17 00:00:00 2001
From: Chris Fallin <chris@cfallin.org>
Date: Sat, 14 Feb 2026 15:17:16 -0800
Subject: [PATCH] Add a few more const fns to deal with registers and machine
 environments.

As part of updating Cranelift to use the new const-fn-friendly
MachineEnv changes in #254, I found I needed a few more bits here.

In particular the `from_bits` method duplicates a `From` impl, but
`From::from` is not a `const fn`, so we can't use it. A little awkward
but this replicates what we've done elsewhere.
---
 src/lib.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/lib.rs b/src/lib.rs
index 1c9fa178..c3af0569 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -257,7 +257,7 @@ impl PRegSet {
     }
 
     /// Add a physical register (PReg) to the set.
-    pub fn add(&mut self, reg: PReg) {
+    pub const fn add(&mut self, reg: PReg) {
         let (index, bit) = Self::split_index(reg);
         self.bits[index] |= 1 << bit;
     }
@@ -462,6 +462,11 @@ impl VReg {
     pub const fn bits(self) -> usize {
         self.bits as usize
     }
+
+    #[inline(always)]
+    pub const fn from_bits(bits: u32) -> VReg {
+        Self { bits }
+    }
 }
 
 impl From<u32> for VReg {