Replace a call of -"string" with frozen string literal at parse time

Author: andrykonchin

CHANGELOG.md

@@ -11,6 +11,7 @@ Compatibility:
 
 Performance:
 
+* Replace a call of `-"string"` with frozen string literal at parse time (@andrykonchin).
 
 Changes:
 

src/main/java/org/truffleruby/parser/BodyTranslator.java

@@ -509,7 +509,8 @@ public RubyNode visitCallNode(CallParseNode node) {
         final ParseNode receiver = node.getReceiverNode();
         final String methodName = node.getName();
 
-        if (receiver instanceof StrParseNode && methodName.equals("freeze")) {
+        if (receiver instanceof StrParseNode &&
+                (methodName.equals("freeze") || methodName.equals("-@"))) {
             final StrParseNode strNode = (StrParseNode) receiver;
             final Rope nodeRope = strNode.getValue();
             final ImmutableRubyString frozenString = language

test/mri/excludes/TestRubyOptimization.rb

@@ -3,7 +3,8 @@
 exclude :test_hash_aref_with, "needs investigation"
 exclude :test_nil_safe_conditional_assign, "needs investigation"
 exclude :test_optimized_rescue, "needs investigation"
-exclude :test_string_freeze, "needs investigation"
+exclude :test_string_freeze, "TruffleRuby does not consider redefined String#freeze on string literals for simplicity"
+exclude :test_string_uminus, "TruffleRuby does not consider redefined String#-@ on string literals for simplicity"
 exclude :test_string_freeze_block, "needs investigation"
 exclude :test_string_freeze_saves_memory, "needs investigation"
 exclude :test_string_length, "needs investigation"