fix redefinition optimization for -"literal string" (UMinus)

Unfortunately this enlarges insns.def by yet another
instruction.  However, it is much prettier than opt_str_freeze
in use, and maybe we can avoid having so many instructions in
the future.

[ruby-core:80368]

* insns.def (DEFINE_INSN): new instruction: opt_str_uminus (maybe temporary)
* compile.c (iseq_compile_each0): split instructions
* test/ruby/test_optimization.rb (test_string_uminus): new test
* vm.c (vm_init_redefined_flag): set redefinintion flag for uminus
* vm_core.h (enum ruby_basic_operators): add BOP_UMINUS

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58144 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 6 insertions, 1 deletions

diff --git a/compile.c b/compile.c
index e3d66b6809..317475b525 100644
--- a/compile.c
+++ b/compile.c
@@ -5211,7 +5211,12 @@ iseq_compile_each0(rb_iseq_t *iseq, LINK_ANCHOR *const ret, NODE *node, int popp
 	    ISEQ_COMPILE_DATA(iseq)->option->specialized_instruction) {
 	    VALUE str = rb_fstring(node->nd_recv->nd_lit);
 	    iseq_add_mark_object(iseq, str);
-	    ADD_INSN1(ret, line, opt_str_freeze, str);
+	    if (node->nd_mid == idUMinus) {
+		ADD_INSN1(ret, line, opt_str_uminus, str);
+	    }
+	    else {
+		ADD_INSN1(ret, line, opt_str_freeze, str);
+	    }
 	    if (popped) {
 		ADD_INSN(ret, line, pop);
 	    }