https://bugs.kde.org/show_bug.cgi?id=490520
Paul Floyd <pjfl...@wanadoo.fr> changed:
What |Removed |Added
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CC| |pjfl...@wanadoo.fr
--- Comment #1 from Paul Floyd <pjfl...@wanadoo.fr> ---
The testcase has been there for 13 years. There is a configure test for loopnel
and if the assembler does not support it the testcase does not get built.
Does that mean that AMD are now making CPUs that have removed this opcode?
GCC supports it https://godbolt.org/z/5Wrqrqev1 and it works fine on my old
Xeon PC.
LLVM doesn't support it
paulf> clang -g -o loopnel loopnel.c
loopnel.c:8:17: error: invalid instruction mnemonic 'loopnel'
asm volatile ("1: addq $1, %0; loopnel 1b" : "+a" (rax), "+c" (rcx) : :
"cc");
^
<inline asm>:1:20: note: instantiated into assembly here
1: addq $1, %rax; loopnel 1b
I ought to look at that one day.
Finally I just tested on a machine that is
Model name: AMD EPYC 7773X 64-Core Processor
and it works OK.
Other than AMD not documenting it (and LLVM not accepting the mnemonic) I don't
see any problem.
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