Failure to build librseq on ppc

Segher Boessenkool segher at kernel.crashing.org
Fri Jul 10 03:37:12 AEST 2020


On Thu, Jul 09, 2020 at 09:43:47AM -0400, Mathieu Desnoyers wrote:
> > What protects r17 *after* this asm statement?
> 
> As discussed in the other leg of the thread (with the code example),
> r17 is in the clobber list of all asm statements using this macro, and
> is used as a temporary register within each inline asm.

That works fine then, for a testcase.  Using r17 is not a great idea for
performance (it increases the active register footprint, and causes more
registers to be saved in the prologue of the functions, esp. on older
compilers), and it is easier to just let the compiler choose a good
register to use.  But maybe you want to see r17 in the generated
testcases, as eyecatcher or something, dunno :-)


Segher


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