From aa6cfb2669e51b3211017bde2faa6eddba22ecbe Mon Sep 17 00:00:00 2001
From: Ben Kimock <kimockb@gmail.com>
Date: Fri, 8 Mar 2024 21:50:23 -0500
Subject: Sink ptrtoint for RMW ops on pointers to cg_llvm

---
 compiler/rustc_codegen_llvm/src/builder.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

(limited to 'compiler/rustc_codegen_llvm/src/builder.rs')

diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs
index ca2e2b57580..63e59ea13fc 100644
--- a/compiler/rustc_codegen_llvm/src/builder.rs
+++ b/compiler/rustc_codegen_llvm/src/builder.rs
@@ -1132,9 +1132,15 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         &mut self,
         op: rustc_codegen_ssa::common::AtomicRmwBinOp,
         dst: &'ll Value,
-        src: &'ll Value,
+        mut src: &'ll Value,
         order: rustc_codegen_ssa::common::AtomicOrdering,
     ) -> &'ll Value {
+        // The only RMW operation that LLVM supports on pointers is compare-exchange.
+        if self.val_ty(src) == self.type_ptr()
+            && op != rustc_codegen_ssa::common::AtomicRmwBinOp::AtomicXchg
+        {
+            src = self.ptrtoint(src, self.type_isize());
+        }
         unsafe {
             llvm::LLVMBuildAtomicRMW(
                 self.llbuilder,
-- 
cgit 1.4.1-3-g733a5