Bugzilla

Here's a reduced test case:
```
let { exports } = new WebAssembly.Instance(new WebAssembly.Module(
    wasmTextToBinary(`
      (module
        (func (export "g")
          (drop
            (block (result i32)
              (i32.clz (i32.const 1))
              (if
                (i32.const 1)
                (return))))))`)));
exports.g();
```

And the corresponding generated code, annotated manually:

```
	.balign 16, 0xf4   ;; hlt
.Llabel0:
	cmpl       $0x1, %r10d
	je         .Lfrom10
	ud2
.Lfrom10:
	push       %r14         ; tls
	push       %rbp         ; saved bp
	movq       %rsp, %rbp   ; 
	movq       %rsp, %rax
	addq       $0x0000, %rax ; reserve stack
	cmpq       %rax, 0x28(%r14) ; check stack
	jb         .Lfrom41
	ud2
.Lfrom41:

	;; beginFunction: enter body with masm.framePushed = 0
	movl       $0x1, %eax   ; i32.const 1
	bsrl       %eax, %eax   ; clz
	jne        .Lfrom57     ; if clz operand wasn't zero, go ahead
	movl       $0x3f, %eax  ; in the zero case, consider as having 63 leading zeroes (?)
.Lfrom57:
	xorl       $31, %eax    ; truncate to maximum 31 zeroes
	movl       $0x1, %ecx   ; push if test operand: 1
	push       %rax         ; save clz result
	testl      %ecx, %ecx   ; test if operand
	je         .Lfrom79
	jmp        .Lfrom84
.Llabel84:
.Lfrom79:
	addq       $8, %rsp
	jmp        .Lfrom93
	;; endFunction: start of function epilogue
	int3
.Lfrom93:
	pop        %rbp
	pop        %r14
	ret
	;; endFunction: end of function epilogue
	;; endFunction: start of OOL code
	;; endFunction: end of OOL code for index 0
	ud2
```

It would seem that the "return" isn't getting compiled correctly in this case.  I will poke.

@gkw -- I am not able to see the pernosco session; though I auth'd my github, it says "You successfully logged in, but either you are not authorized to view this trace OR the debugging database for this trace has expired (typically 7 days after the trace was collected) and needs to be rebuilt. "

Here's a reduced test case:
```js
let { exports } = new WebAssembly.Instance(new WebAssembly.Module(
    wasmTextToBinary(`
      (module
        (func (export "g")
          (drop
            (block (result i32)
              (i32.clz (i32.const 1))
              (if
                (i32.const 1)
                (return))))))`)));
exports.g();
```

And the corresponding generated code, annotated manually:

```asm
	.balign 16, 0xf4   ;; hlt
.Llabel0:
	cmpl       $0x1, %r10d
	je         .Lfrom10
	ud2
.Lfrom10:
	push       %r14         ; tls
	push       %rbp         ; saved bp
	movq       %rsp, %rbp   ; 
	movq       %rsp, %rax
	addq       $0x0000, %rax ; reserve stack
	cmpq       %rax, 0x28(%r14) ; check stack
	jb         .Lfrom41
	ud2
.Lfrom41:

	;; beginFunction: enter body with masm.framePushed = 0
	movl       $0x1, %eax   ; i32.const 1
	bsrl       %eax, %eax   ; clz
	jne        .Lfrom57     ; if clz operand wasn't zero, go ahead
	movl       $0x3f, %eax  ; in the zero case, consider as having 63 leading zeroes (?)
.Lfrom57:
	xorl       $31, %eax    ; truncate to maximum 31 zeroes
	movl       $0x1, %ecx   ; push if test operand: 1
	push       %rax         ; save clz result
	testl      %ecx, %ecx   ; test if operand
	je         .Lfrom79
	jmp        .Lfrom84
.Llabel84:
.Lfrom79:
	addq       $8, %rsp
	jmp        .Lfrom93
	;; endFunction: start of function epilogue
	int3
.Lfrom93:
	pop        %rbp
	pop        %r14
	ret
	;; endFunction: end of function epilogue
	;; endFunction: start of OOL code
	;; endFunction: end of OOL code for index 0
	ud2
```

It would seem that the "return" isn't getting compiled correctly in this case.  I will poke.

@gkw -- I am not able to see the pernosco session; though I auth'd my github, it says "You successfully logged in, but either you are not authorized to view this trace OR the debugging database for this trace has expired (typically 7 days after the trace was collected) and needs to be rebuilt. "