Forgot to copy llvmdev.

I think this part of the diff was a mistake. That Requires check still needs to be there.

 let Uses = \[RCX\] in  
 def JRCXZ : Ii8PCRel<0xE3, RawFrm, (outs), (ins brtarget8:$dst),  
\- "jrcxz\\t$dst", \[\], IIC\_JCXZ>, AdSize64, Requires<\[In64BitMode\]>;  
\+ "jrcxz\\t$dst", \[\], IIC\_JCXZ>, AdSize64;

I'll fix sometime this weekend.

On Thu, Jul 2, 2015 at 3:55 PM, Li, Charles <charles\_li@playstation.sony.com> wrote:

Hi Craig,

I am Charles Li from Sony Playstation.

We are doing x86 code gen testing and, by chance, we noticed that compiling the 64-bit assembly instruction “jrcxz” in 32-bit mode “-m32”

previously resulted in an error,

now gets silently converted into the 32-bit equivalent instruction “jecxz”.

I have bisected this change in behavior down to r225075 - \[X86\] Make the instructions that use AdSize16/32/64 co-exist together without using mode predicates.

I am curious if this change in behavior was an intended feature or perhaps a side effect.

Here is my methodology.

The asm test case.

$ cat j64.s

jrcxz foo

foo:

Compiling the test case in 32-bit mode with Clang r225039.

$ r225039/clang.exe j64.s -c -m32 -target x86\_64-pc-linux-gnu

j64.s:1:9: error: instruction requires: 64-bit mode

jrcxz foo

^

Compiling the test case in 32-bit mode with Clang r225079 then disassembling the obj file to look for the jump instruction.

$ r225079/clang.exe j64.s -c -m32 -target x86\_64-pc-linux-gnu

(No Error)

$ objdump j64.o -d | grep j

j64.o: file format elf32-i386

0: e3 00 jecxz 2

Just FYI, this is not blocking us in any way. I found this to be a very interesting discovery so I want to share it in the hopes of determining if it was intentional or not.

Sincerely,

Charles Li

--

\~Craig