https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100163
--- Comment #2 from Victor Luchitz <vluchits at gmail dot com> --- Here's relevant -S output for -O2: ... sub r1,r15 .align 2 .L186: mov.w @r2,r0 extu.w r0,r4 And for -O2 -fno-align-loops: ... sub r1,r15 .L186: mov.w @r2,r0 extu.w r0,r4 I'm not sure what's workarounds are available for an end user here other than to explicitly disable all kinds of alignments.