de-rust phase-0: archive Rust LLVM backend to archive/rust-llvm-backend (RESTORE documented); defaults unaffected

archive/rust-llvm-backend/llvm/compiler/codegen/instructions/select.rs

@@ -0,0 +1,28 @@
+/*!
+ * Select & Condition helpers (scaffolding)
+ *
+ * Placeholder for condition normalization / short-circuit pre-processing
+ * to keep `function.rs` focused on structure. Implementations will be
+ * added incrementally; for now, this module is documentation-only.
+ */
+
+use crate::mir::{function::MirFunction, ValueId};
+use crate::mir::MirType;
+use super::super::types; // access mapping helpers if needed later
+
+/// Normalize a branch condition if needed (scaffolding).
+/// Currently returns the input unchanged; provides a single place
+/// to adjust semantics later (e.g., truthy rules, short-circuit pre-pass).
+pub(crate) fn normalize_branch_condition(func: &MirFunction, cond: &ValueId) -> ValueId {
+    // Minimal truthy normalization hook.
+    // Strategy (no new instructions here):
+    // - If we have a recorded type for `cond` and it is a boolean-like i1/i64 (0/1), return as-is.
+    // - Otherwise, return the original cond and let flow/emit handle `!= 0` lowering as today.
+    if let Some(ty) = func.metadata.value_types.get(cond) {
+        match ty {
+            MirType::I1 | MirType::I64 | MirType::Bool => { return *cond; }
+            _ => {}
+        }
+    }
+    *cond
+}