----- Segher Boessenkool <seg...@kernel.crashing.org> wrote: > Hi! > > On Wed, Jul 08, 2020 at 10:27:27PM +1000, Michael Ellerman wrote: > > Segher Boessenkool <seg...@kernel.crashing.org> writes: > > > You'll have to show the actual failing machine code, and with enough > > > context that we can relate this to the source code. > > > > > > -save-temps helps, or use -S instead of -c, etc. > > > > Attached below. > > Thanks! > > > I think that's from: > > > > #define LOAD_WORD "ld " > > > > #define RSEQ_ASM_OP_CMPEQ(var, expect, label) > > \ > > LOAD_WORD "%%r17, %[" __rseq_str(var) "]\n\t" > > \ > > The way this hardcodes r17 *will* break, btw. The compiler will not > likely want to use r17 as long as your code (after inlining etc.!) stays > small, but there is Murphy's law.
r17 is in the clobber list, so it should be ok. > > Anyway... something in rseq_str is wrong, missing %X<n>. This may > have to do with the abuse of inline asm here, making a fix harder :-( I just committed a fix which enhances the macros. Thanks for your help! Mathieu > > > Segher -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
