x86_64 asm: Build error when using r[8-15]b #485
Description
The following code passes build with cg_llvm, but fails with cg_gcc.
#[inline(never)]
pub unsafe fn f() {
core::arch::asm!(
"",
out("al") _,
out("bl") _,
out("cl") _,
out("dl") _,
out("sil") _,
out("dil") _,
// out("bpl") _, // frame pointer
out("r8b") _,
out("r9b") _,
out("r10b") _,
out("r11b") _,
out("r12b") _,
out("r13b") _,
out("r14b") _,
out("r15b") _,
);
}The following is the error message when building with cg_gcc.
libgccjit.so: error: unknown register name 'r15b' in 'asm'
libgccjit.so: error: unknown register name 'r14b' in 'asm'
libgccjit.so: error: unknown register name 'r13b' in 'asm'
libgccjit.so: error: unknown register name 'r12b' in 'asm'
libgccjit.so: error: unknown register name 'r11b' in 'asm'
libgccjit.so: error: unknown register name 'r10b' in 'asm'
libgccjit.so: error: unknown register name 'r9b' in 'asm'
libgccjit.so: error: unknown register name 'r8b' in 'asm'
error: could not copy "/app/output.example.fb61ce7e3f5ff483-cgu.0.rcgu.s" to "/app/output.s": No such file or directory (os error 2)
I could reproduce this with both playground and the latest master branch (75f0ab5).
Reference: https://doc.rust-lang.org/nightly/reference/inline-assembly.html#register-operands
Architecture Register class Registers LLVM constraint code x86-64 reg_byte*al,bl,cl,dl,sil,dil,bpl,r[8-15]bq