In D125789#3519538, @craig.topper wrote:

Is it gcc that needs a fix or binutils?

In D125789#3519493, @pengfei wrote:

In D125789#3519433, @sheisc wrote:

In D125789#3519411, @pengfei wrote:

I think another way is to report the issue to GCC. From the perspective of the user, GCC should support both {%k1} {z} and {%k1}{z}. Then we don't need the clange on LLVM.

Yes. It is a good idea.
However, it appears that there is no such white space in the instructions as described in Intel's manuals.
So I don't know which one should be the correct format.
Anyway, not a big issue.
I found this problem when using the fuzzer (i.e. AFL) to build Firefox.

Yeah. This is an interesting question. I didn't notice the difference between LLVM and GCC. I think either way changing here or GCC is OK :)

In D125789#3519411, @pengfei wrote:

I think another way is to report the issue to GCC. From the perspective of the user, GCC should support both {%k1} {z} and {%k1}{z}. Then we don't need the clange on LLVM.

In D125789#3519361, @pengfei wrote:

I guess a lot of lines of tests need to update

$ grep -rn " {z}" llvm/test/CodeGen/X86/ | wc -l
7797