From df4cf5b6d2d8c4f862f6153e069289244b08e251 Mon Sep 17 00:00:00 2001
From: Lucian Popescu <lucian.popescu@tecnico.ulisboa.pt>
Date: Mon, 25 May 2026 13:11:37 +0100
Subject: [PATCH] Add support for arch-specific rules

---
 rule-preprocessor/src/syntactic.rs | 5 +++++
 rules/builtin/src.cpp              | 3 +++
 rules/builtin/tgt_unsafe.rs        | 4 ++++
 3 files changed, 12 insertions(+)

diff --git a/rule-preprocessor/src/syntactic.rs b/rule-preprocessor/src/syntactic.rs
index 855ffc05..191dac3c 100644
--- a/rule-preprocessor/src/syntactic.rs
+++ b/rule-preprocessor/src/syntactic.rs
@@ -56,6 +56,11 @@ fn cfg_matches_host(fn_item: &ast::Fn) -> bool {
                 "macos" => cfg!(target_os = "macos"),
                 other => panic!("unsupported target_os in cfg: {other}"),
             },
+            Predicate::Target(TargetPredicate::Arch(arch)) => match arch.as_str() {
+                "x86_64" => cfg!(target_arch = "x86_64"),
+                "x86" => cfg!(target_arch = "x86"),
+                other => panic!("unsupported target_arch in cfg: {other}"),
+            },
             _ => panic!("unsupported cfg predicate in `{meta_text}`"),
         });
         if !matches {
diff --git a/rules/builtin/src.cpp b/rules/builtin/src.cpp
index 26da1699..f52cf5a8 100644
--- a/rules/builtin/src.cpp
+++ b/rules/builtin/src.cpp
@@ -23,3 +23,6 @@ int f7(unsigned long x) { return __builtin_ctzl(x); }
 int f8(unsigned long x) { return __builtin_popcountl(x); }
 bool f9(long a, long b, long *r) { return __builtin_mul_overflow(a, b, r); }
 bool f10(long long a, long long b, long long *r) { return __builtin_mul_overflow(a, b, r); }
+#if defined(__x86_64__) || defined(__i386__)
+void f11(void) { return __builtin_ia32_pause(); }
+#endif
diff --git a/rules/builtin/tgt_unsafe.rs b/rules/builtin/tgt_unsafe.rs
index d2f94f66..16638e3f 100644
--- a/rules/builtin/tgt_unsafe.rs
+++ b/rules/builtin/tgt_unsafe.rs
@@ -35,3 +35,7 @@ unsafe fn f10(a0: i64, a1: i64, a2: *mut i64) -> bool {
     *a2 = val;
     ovf
 }
+#[cfg(any(target_arch = "x86_64", target_arch = "x86"))]
+unsafe fn f11() {
+    std::hint::spin_loop();
+}