https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122611
--- Comment #3 from Ionuț Nicula <nicula at nicula dot xyz> ---
Disregarding the valgrind output for a second, in gdb I am hitting those lines
while single-stepping in assembly:
vmovdqa xmm1, XMMWORD PTR [rax]
vmovdqa xmm10, XMMWORD PTR [rax+16]
vmovdqa xmm8, XMMWORD PTR [rax+32]
vmovdqa xmm0, XMMWORD PTR [rax+48]
rax is 0x4172b0 (the start of the buffer), so doing an XMMWORD load from rax+48
will be outside the buffer. I don't see how the `if` semantics aren't being
violated, since we're reading outside of the 4-byte buffer.
