zhanjunl added a comment.
>From my understanding, gas only supports some of the possible s390 instruction formats when using ".insn". For example, the "ri" format in the insn directive corresponds to the RI-a format, which uses an immediate field and not a relative-immediate field. Therefore, for the .insn directive specifically:
ri = RI-a
rie = RIE-d
ril = RIL-a
I tried assembling a sample .insn directive with gas:
.text
.globl main
.type main, at function
main:
lghi %r2, 0
# brct %r2,.label
.insn ri,0xa7060000,%r2,.label
.label:
br %r14
.Lfunc_end0:
.size main, .Lfunc_end0-main
gas will assemble the above code with no errors, but when I do an objdump of the object file, I see:
temp.o: file format elf64-s390
Disassembly of section .text:
0000000000000000 <main>:
0: a7 29 00 00 lghi %r2,0
4: a7 26 00 00 brct %r2,4 <main+0x4>
0000000000000008 <.label>:
8: 07 fe br %r14
a: 07 07 nopr %r7
So it looks like it was able to get the correct instruction mnemonic, but it silently fails when trying to encode the label into the instruction. This was my understanding when supporting the .insn, and so I didn't expect to have to do any fixups. Unless I'm mistaken?
http://reviews.llvm.org/D21809