Annotate Regexp#casefold?

Author: st0012

test/ruby/test_zjit.rb

@@ -840,6 +840,26 @@ def test(x)
     }, call_threshold: 1, insns: [:branchnil]
   end
 
+  def test_regexp_casefold_true
+    assert_compiles 'true', %q{
+      def test
+        /hello/i.casefold?
+      end
+      test
+      test
+    }
+  end
+
+  def test_regexp_casefold_false
+    assert_compiles 'false', %q{
+      def test
+        /hello/.casefold?
+      end
+      test
+      test
+    }
+  end
+
   # tool/ruby_vm/views/*.erb relies on the zjit instructions a) being contiguous and
   # b) being reliably ordered after all the other instructions.
   def test_instruction_order

zjit/src/cruby_methods.rs

@@ -80,6 +80,7 @@ pub fn init() -> Annotations {
     annotate!(rb_cModule, "===", types::BoolExact, no_gc, leaf);
     annotate!(rb_cArray, "length", types::Fixnum, no_gc, leaf, elidable);
     annotate!(rb_cArray, "size", types::Fixnum, no_gc, leaf, elidable);
+    annotate!(rb_cRegexp, "casefold?", types::BoolExact, no_gc, leaf, elidable);
 
     Annotations {
         cfuncs: std::mem::take(cfuncs)

zjit/src/hir.rs

@@ -4620,6 +4620,19 @@ mod tests {
               SideExit
         "#]]);
     }
+
+    #[test]
+    fn test_regexp_type() {
+        eval("
+            def test = /a/
+        ");
+        assert_method_hir("test", expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v2:RegexpExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+              Return v2
+        "#]]);
+    }
 }
 
 #[cfg(test)]
@@ -6312,16 +6325,19 @@ mod opt_tests {
     }
 
     #[test]
-    fn test_regexp_type() {
+    fn test_regexp_casefold() {
         eval("
-            def test = /a/
+            def test = /hello/i.casefold?
+            test
             test
         ");
         assert_optimized_method_hir("test", expect![[r#"
             fn test:
             bb0(v0:BasicObject):
               v2:RegexpExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
-              Return v2
+              PatchPoint MethodRedefined(Regexp@0x1008, casefold?@0x1010)
+              v7:BoolExact = CCall casefold?@0x1018, v2
+              Return v7
         "#]]);
     }
 }