https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96034
sshannin at gmail dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |INVALID
Status|UNCONFIRMED |RESOLVED
--- Comment #2 from sshannin at gmail dot com ---
Ah, yes, you're correct on both counts.
For future reference if anybody comes across this, I can confirm on both a
sandy bridge and skylake that the pxor does actually make it faster. I
should've checked first; I got too excited by "fewer instructions = better".
As far as the ABI, I'm certainly not an expert and if you claim that the upper
bits are undefined I certainly defer to you. As you intuited, I was checking
against llvm output (and it does omit the sign extend).
Sorry for the bother and thanks for such a helpful response.
