diff --git a/src/codegen/llvm/Builder.zig b/src/codegen/llvm/Builder.zig
index d20a41e3f5..fbdc6bd440 100644
--- a/src/codegen/llvm/Builder.zig
+++ b/src/codegen/llvm/Builder.zig
@@ -7340,7 +7340,8 @@ const MemoryAccessInfo = packed struct(u32) {
     _: u13 = undefined,
 };
 
-pub const FastMath = packed struct(u32) {
+pub const FastMath = packed struct(u8) {
+    unsafe_algebra: bool = false, // Legacy
     nnan: bool = false,
     ninf: bool = false,
     nsz: bool = false,