bjit+rewriter: use const_loader.loadConstIntoReg more often

this saves a few bytes by replacing some movabs imm64, reg with smaller instructions

src/asm_writing/rewriter.cpp

@@ -1036,7 +1036,7 @@ void Rewriter::_setupCall(bool has_side_effects, llvm::ArrayRef<RewriterVar*> ar
             uintptr_t counter_addr = (uintptr_t)(&picked_slot->num_inside);
             if (isLargeConstant(counter_addr)) {
                 assembler::Register reg = allocReg(Location::any(), preserve);
-                assembler->mov(assembler::Immediate(counter_addr), reg);
+                const_loader.loadConstIntoReg(counter_addr, reg);
                 assembler->incl(assembler::Indirect(reg, 0));
             } else {
                 assembler->incl(assembler::Immediate(counter_addr));
@@ -1540,7 +1540,7 @@ void Rewriter::commit() {
         uintptr_t counter_addr = (uintptr_t)(&picked_slot->num_inside);
         if (isLargeConstant(counter_addr)) {
             assembler::Register reg = allocReg(Location::any(), getReturnDestination());
-            assembler->mov(assembler::Immediate(counter_addr), reg);
+            const_loader.loadConstIntoReg(counter_addr, reg);
             assembler->decl(assembler::Indirect(reg, 0));
         } else {
             assembler->decl(assembler::Immediate(counter_addr));

src/codegen/baseline_jit.cpp

@@ -1011,8 +1011,7 @@ void JitFragmentWriter::_emitGetLocal(RewriterVar* val_var, const char* name) {
     _setupCall(false, {});
     {
         assembler::ForwardJump jnz(*assembler, assembler::COND_NOT_ZERO);
-        assembler->mov(assembler::Immediate((uint64_t)name), assembler::RDI);
-
+        const_loader.loadConstIntoReg((uint64_t)name, assembler::RDI);
         _callOptimalEncoding(assembler::R11, (void*)assertNameDefinedHelper);
 
         registerDecrefInfoHere();