diff --git a/bootstraptest/test_yjit.rb b/bootstraptest/test_yjit.rb
index fcda5476ea..2da9086a60 100644
--- a/bootstraptest/test_yjit.rb
+++ b/bootstraptest/test_yjit.rb
@@ -89,6 +89,20 @@ assert_equal '0', %q{
     retval = foo()
 }
 
+# Passing argument types to callees
+assert_equal '8.5', %q{
+    def foo(x, y)
+        x + y
+    end
+
+    def bar
+        foo(7, 1.5)
+    end
+
+    bar
+    bar
+}
+
 # Recursive Ruby-to-Ruby calls
 assert_equal '21', %q{
     def fib(n)
diff --git a/yjit_codegen.c b/yjit_codegen.c
index 7e98e21a55..201e2c5fae 100644
--- a/yjit_codegen.c
+++ b/yjit_codegen.c
@@ -257,13 +257,13 @@ yjit_entry_prologue(void)
     return code_ptr;
 }
 
-
 // Generate code to check for interrupts and take a side-exit
 static void
 yjit_check_ints(codeblock_t* cb, uint8_t* side_exit)
 {
     // Check for interrupts
     // see RUBY_VM_CHECK_INTS(ec) macro
+    ADD_COMMENT(cb, "RUBY_VM_CHECK_INTS(ec)");
     mov(cb, REG0_32, member_opnd(REG_EC, rb_execution_context_t, interrupt_mask));
     not(cb, REG0_32);
     test(cb, member_opnd(REG_EC, rb_execution_context_t, interrupt_flag), REG0_32);
@@ -289,7 +289,6 @@ jit_jump_to_next_insn(jitstate_t *jit, const ctx_t *current_context)
     );
 }
 
-
 // Compile a sequence of bytecode instructions for a given basic block version
 void
 yjit_gen_block(ctx_t *ctx, block_t *block, rb_execution_context_t *ec)
@@ -350,9 +349,9 @@ yjit_gen_block(ctx_t *ctx, block_t *block, rb_execution_context_t *ec)
             break;
         }
 
-        if (1) {
+        if (0) {
             fprintf(stderr, "compiling %d: %s\n", insn_idx, insn_name(opcode));
-            //print_str(cb, insn_name(opcode));
+            print_str(cb, insn_name(opcode));
         }
 
         // :count-placement:
@@ -518,41 +517,24 @@ gen_putself(jitstate_t* jit, ctx_t* ctx)
     return YJIT_KEEP_COMPILING;
 }
 
+// Compute the index of a local variable from its slot index
+uint32_t slot_to_local_idx(const rb_iseq_t *iseq, int32_t slot_idx)
+{
+    // Convoluted rules from local_var_name() in iseq.c
+    int32_t local_table_size = iseq->body->local_table_size;
+    int32_t op = slot_idx - VM_ENV_DATA_SIZE;
+    int32_t local_idx = local_idx = local_table_size - op - 1;
+    RUBY_ASSERT(local_idx >= 0 && local_idx < local_table_size);
+    return (uint32_t)local_idx;
+}
+
 static codegen_status_t
 gen_getlocal_wc0(jitstate_t* jit, ctx_t* ctx)
 {
     // Compute the offset from BP to the local
-    int32_t local_idx = (int32_t)jit_get_arg(jit, 0);
-    const int32_t offs = -(SIZEOF_VALUE * local_idx);
-
-
-
-    /*
-    if (local_idx < 8)
-    {
-        val_type_t local_type = ctx->local_types[local_idx];
-
-        if (local_type.type == ETYPE_FIXNUM) {
-            fprintf(stderr, "local_idx=%d is fixnum\n", local_idx);
-            ADD_COMMENT(cb, "local is fixnum");
-        }
-        else {
-            fprintf(stderr, "local_idx=%d not fixnum\n", local_idx);
-            ADD_COMMENT(cb, "local not fixnum");
-        }
-    }
-    else
-    {
-        fprintf(stderr, "local_idx=%d\n", local_idx);
-    }
-    */
-
-
-    fprintf(stderr, "local_idx=%d\n", local_idx);
-
-
-
-
+    int32_t slot_idx = (int32_t)jit_get_arg(jit, 0);
+    const int32_t offs = -(SIZEOF_VALUE * slot_idx);
+    uint32_t local_idx = slot_to_local_idx(jit->iseq, slot_idx);
 
     // Load environment pointer EP from CFP
     mov(cb, REG0, member_opnd(REG_CFP, rb_control_frame_t, ep));
@@ -610,7 +592,8 @@ gen_setlocal_wc0(jitstate_t* jit, ctx_t* ctx)
     }
     */
 
-    int32_t local_idx = (int32_t)jit_get_arg(jit, 0);
+    int32_t slot_idx = (int32_t)jit_get_arg(jit, 0);
+    uint32_t local_idx = slot_to_local_idx(jit->iseq, slot_idx);
 
     // Load environment pointer EP from CFP
     mov(cb, REG0, member_opnd(REG_CFP, rb_control_frame_t, ep));
@@ -634,7 +617,7 @@ gen_setlocal_wc0(jitstate_t* jit, ctx_t* ctx)
     mov(cb, REG1, stack_top);
 
     // Write the value at the environment pointer
-    const int32_t offs = -8 * local_idx;
+    const int32_t offs = -8 * slot_idx;
     mov(cb, mem_opnd(64, REG0, offs), REG1);
 
     return YJIT_KEEP_COMPILING;
@@ -1728,7 +1711,7 @@ gen_oswb_iseq(jitstate_t *jit, ctx_t *ctx, const struct rb_callinfo *ci, const r
     lea(cb, REG0, ctx_sp_opnd(ctx, sizeof(VALUE) * -(argc + 1)));
     mov(cb, member_opnd(REG_CFP, rb_control_frame_t, sp), REG0);
 
-    // Store the next PC i the current frame
+    // Store the next PC in the current frame
     mov(cb, REG0, const_ptr_opnd(jit->pc + insn_len(BIN(opt_send_without_block))));
     mov(cb, mem_opnd(64, REG_CFP, offsetof(rb_control_frame_t, pc)), REG0);