Ard, With link time optimization, the current order produces smaller code.
Without link time optimization, your patch will produce smaller code, but not as small as link time optimized code. Mike > -----Original Message----- > From: edk2-devel [mailto:[email protected]] > On Behalf Of Ard Biesheuvel > Sent: Thursday, December 7, 2017 9:13 AM > To: Kinney, Michael D <[email protected]> > Cc: Alexei Fedorov <[email protected]>; edk2- > [email protected]; Gao, Liming <[email protected]>; > Leif Lindholm <[email protected]> > Subject: Re: [edk2] [PATCH] MdePkg/DebugLib; swap if > conditions in ASSERT_[EFI|RETURN]_ERROR > > On 7 December 2017 at 17:09, Ard Biesheuvel > <[email protected]> wrote: > > On 7 December 2017 at 17:01, Kinney, Michael D > > <[email protected]> wrote: > >> Ard, > >> > >> The reason for the current ordering is for size > optimization. > >> > >> The most common implementation of DebugAssertEnabled() > uses > >> a FixedAtBuild PCD to determine if these are enabled. > The > >> check of status can be optimized away if they are > disabled. > >> If you reverse them, then the status check is always > performed. > >> > > > > DebugAssertEnabled() is a function call that gets > resolved at link > > time, and is not annotated as being free of side > effects. So I agree > > that the implementation of that function could be > optimized into a > > 'return true' or 'return false' depending on the > compile time values > > of those PCDs, but the way the macro is defined > currently, it still > > requires the function call to be made, and the > conditional compare > > with a constant that follows will still be present in > the code. > > > > What I am suggesting is to replace it with a comparison > with a > > constant, and a conditional function call instead. This > will not > > affect code size, but will only remove needless > function calls at > > runtime. > > Please refer to these threads for details: > https://lists.01.org/pipermail/edk2-devel/2017- > December/018790.html > https://lists.01.org/pipermail/edk2-devel/2017- > December/018809.html > _______________________________________________ > edk2-devel mailing list > [email protected] > https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
