ZJIT: Inline Array#length

3 files changed, 37 insertions, 28 deletions

diff --git a/zjit/src/cruby_methods.rs b/zjit/src/cruby_methods.rs
index 4aa9068cb1..e6c26148cf 100644
--- a/zjit/src/cruby_methods.rs
+++ b/zjit/src/cruby_methods.rs
@@ -219,8 +219,7 @@ pub fn init() -> Annotations {
     annotate!(rb_cString, "ascii_only?", types::BoolExact, no_gc, leaf);
     annotate!(rb_cModule, "name", types::StringExact.union(types::NilClass), no_gc, leaf, elidable);
     annotate!(rb_cModule, "===", inline_module_eqq, 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_cArray, "length", inline_array_length, types::Fixnum, no_gc, leaf, elidable);
     annotate!(rb_cArray, "empty?", types::BoolExact, no_gc, leaf, elidable);
     annotate!(rb_cArray, "reverse", types::ArrayExact, leaf, elidable);
     annotate!(rb_cArray, "join", types::StringExact);
@@ -537,6 +536,17 @@ fn inline_module_eqq(fun: &mut hir::Function, block: hir::BlockId, recv: hir::In
     None
 }
 
+fn inline_array_length(fun: &mut hir::Function, block: hir::BlockId, recv: hir::InsnId, args: &[hir::InsnId], state: hir::InsnId) -> Option<hir::InsnId> {
+    let &[] = args else { return None; };
+    if fun.likely_a(recv, types::Array, state) {
+        let recv = fun.coerce_to(block, recv, types::Array, state);
+        let length_cint = fun.push_insn(block, hir::Insn::ArrayLength { array: recv });
+        let result = fun.push_insn(block, hir::Insn::BoxFixnum { val: length_cint, state });
+        return Some(result);
+    }
+    None
+}
+
 fn inline_integer_succ(fun: &mut hir::Function, block: hir::BlockId, recv: hir::InsnId, args: &[hir::InsnId], state: hir::InsnId) -> Option<hir::InsnId> {
     if !args.is_empty() { return None; }
     if fun.likely_a(recv, types::Fixnum, state) {
diff --git a/zjit/src/hir.rs b/zjit/src/hir.rs
index c6a104fbd1..41ddb3ae69 100644
--- a/zjit/src/hir.rs
+++ b/zjit/src/hir.rs
@@ -1027,6 +1027,7 @@ impl Insn {
             // NewHash's operands may be hashed and compared for equality, which could have
             // side-effects.
             Insn::NewHash { elements, .. } => !elements.is_empty(),
+            Insn::ArrayLength { .. } => false,
             Insn::ArrayDup { .. } => false,
             Insn::HashDup { .. } => false,
             Insn::Test { .. } => false,
diff --git a/zjit/src/hir/opt_tests.rs b/zjit/src/hir/opt_tests.rs
index 3ad07596b7..4fc47dc611 100644
--- a/zjit/src/hir/opt_tests.rs
+++ b/zjit/src/hir/opt_tests.rs
@@ -2291,7 +2291,7 @@ mod hir_opt_tests {
     fn eliminate_array_length() {
         eval("
             def test
-              x = [].length
+              [].length
               5
             end
         ");
@@ -2300,21 +2300,18 @@ mod hir_opt_tests {
         bb0():
           EntryPoint interpreter
           v1:BasicObject = LoadSelf
-          v2:NilClass = Const Value(nil)
-          Jump bb2(v1, v2)
-        bb1(v5:BasicObject):
+          Jump bb2(v1)
+        bb1(v4:BasicObject):
           EntryPoint JIT(0)
-          v6:NilClass = Const Value(nil)
-          Jump bb2(v5, v6)
-        bb2(v8:BasicObject, v9:NilClass):
-          v13:ArrayExact = NewArray
+          Jump bb2(v4)
+        bb2(v6:BasicObject):
+          v10:ArrayExact = NewArray
           PatchPoint MethodRedefined(Array@0x1000, length@0x1008, cme:0x1010)
           PatchPoint NoSingletonClass(Array@0x1000)
           IncrCounter inline_cfunc_optimized_send_count
-          v29:Fixnum = CCall v13, :Array#length@0x1038
-          v20:Fixnum[5] = Const Value(5)
+          v17:Fixnum[5] = Const Value(5)
           CheckInterrupts
-          Return v20
+          Return v17
         ");
     }
 
@@ -2435,7 +2432,7 @@ mod hir_opt_tests {
     fn eliminate_array_size() {
         eval("
             def test
-              x = [].size
+              [].size
               5
             end
         ");
@@ -2444,21 +2441,18 @@ mod hir_opt_tests {
         bb0():
           EntryPoint interpreter
           v1:BasicObject = LoadSelf
-          v2:NilClass = Const Value(nil)
-          Jump bb2(v1, v2)
-        bb1(v5:BasicObject):
+          Jump bb2(v1)
+        bb1(v4:BasicObject):
           EntryPoint JIT(0)
-          v6:NilClass = Const Value(nil)
-          Jump bb2(v5, v6)
-        bb2(v8:BasicObject, v9:NilClass):
-          v13:ArrayExact = NewArray
+          Jump bb2(v4)
+        bb2(v6:BasicObject):
+          v10:ArrayExact = NewArray
           PatchPoint MethodRedefined(Array@0x1000, size@0x1008, cme:0x1010)
           PatchPoint NoSingletonClass(Array@0x1000)
           IncrCounter inline_cfunc_optimized_send_count
-          v29:Fixnum = CCall v13, :Array#size@0x1038
-          v20:Fixnum[5] = Const Value(5)
+          v17:Fixnum[5] = Const Value(5)
           CheckInterrupts
-          Return v20
+          Return v17
         ");
     }
 
@@ -3554,8 +3548,9 @@ mod hir_opt_tests {
           v18:ArrayExact = NewArray v11, v12
           PatchPoint MethodRedefined(Array@0x1000, length@0x1008, cme:0x1010)
           PatchPoint NoSingletonClass(Array@0x1000)
+          v29:CInt64 = ArrayLength v18
+          v30:Fixnum = BoxFixnum v29
           IncrCounter inline_cfunc_optimized_send_count
-          v30:Fixnum = CCall v18, :Array#length@0x1038
           CheckInterrupts
           Return v30
         ");
@@ -3581,8 +3576,9 @@ mod hir_opt_tests {
           v18:ArrayExact = NewArray v11, v12
           PatchPoint MethodRedefined(Array@0x1000, size@0x1008, cme:0x1010)
           PatchPoint NoSingletonClass(Array@0x1000)
+          v29:CInt64 = ArrayLength v18
+          v30:Fixnum = BoxFixnum v29
           IncrCounter inline_cfunc_optimized_send_count
-          v30:Fixnum = CCall v18, :Array#size@0x1038
           CheckInterrupts
           Return v30
         ");
@@ -7170,8 +7166,9 @@ mod hir_opt_tests {
           PatchPoint MethodRedefined(Array@0x1000, length@0x1008, cme:0x1010)
           PatchPoint NoSingletonClass(Array@0x1000)
           v23:ArrayExact = GuardType v9, ArrayExact
+          v24:CInt64 = ArrayLength v23
+          v25:Fixnum = BoxFixnum v24
           IncrCounter inline_cfunc_optimized_send_count
-          v25:Fixnum = CCall v23, :Array#length@0x1038
           CheckInterrupts
           Return v25
         ");
@@ -7198,8 +7195,9 @@ mod hir_opt_tests {
           PatchPoint MethodRedefined(Array@0x1000, size@0x1008, cme:0x1010)
           PatchPoint NoSingletonClass(Array@0x1000)
           v23:ArrayExact = GuardType v9, ArrayExact
+          v24:CInt64 = ArrayLength v23
+          v25:Fixnum = BoxFixnum v24
           IncrCounter inline_cfunc_optimized_send_count
-          v25:Fixnum = CCall v23, :Array#size@0x1038
           CheckInterrupts
           Return v25
         ");