Backport fix for znver1 miscompilation#28

Merged

alexcrichton merged 1 commit intorust-lang:rustc/9.0-2019-09-19from

mati865:znver1_fix

Nov 29, 2019

Commits on Nov 29, 2019

Teach the regmask clobber check to check if any subregister is preserved before considering the super register clobbered

topperc
authored and
mati865
committed