Re: [PATCH] x86: efi: avoid BUILD_BUG_ON() for non-constant p4d_index
From: Borislav Petkov <bp@alien8.de>
Date: 2021-01-15 19:19:37
Also in:
lkml, platform-driver-x86
On Fri, Jan 15, 2021 at 02:11:25PM -0500, Arvind Sankar wrote:
That's how build-time assertions work: they are _supposed_ to be optimized away completely when the assertion is true. If they're _not_ optimized away, the build will fail.
Yah, that I know, thanks.
If gcc really inlines p4d_index() and does a lot more aggressive
optimization to determine that the condition is false and thus optimize
everything away (and clang doesn't), then that would explain the
observation.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette