Re: [fpc-devel] Some thoughts on multi-line string support, and a possible syntax that I think is perfectly clean and Pascal-ish.
On Sat, Jul 6, 2019 at 10:03 AM Ben Grasset wrote: > On Sat, Jul 6, 2019 at 2:15 AM Tony via fpc-devel < > fpc-devel@lists.freepascal.org> wrote: > >> On Thu, 4 Jul 2019 12:00:07 +0200 >> Marco van de Voort wrote: >> >> > In conclusion: it is a solution in search of a problem, with bad >> > behaviour in errorhandling (when unbalanced the compiler errors on >> > perfectly fine code in the wrong place after whatever ' closes the >> > unbalanced ) on top of it. >> > >> > This is why the feature goes against the grain of Pascal IMHO. >> >> Well said Marco! I have been reading this mailing list for some time >> and have been disturbed recently-ish by how often suggestions come up >> for "my pet feature from another language" or "a cool idea I just >> had" (I am probably doing an injustice to some of the suggestions, but >> often they feel deeply un-Pascal-ish - I can't define it but I know it >> when I see it). In these circumstances, a healthy scepticism and >> conservatism among the development team is a good thing. >> > > I think you are certainly doing injustice to a lot of things. Furthermore, > you realize it is possible, to just, you know, make the compiler give > better errors when necessary / desired? > > I intend to add something like this for unterminated multi-line strings, > most likely once I'm done writing my tests and have submitted a formal > patch on the bugtracker. > I've now actually done this, for the record: https://bugs.freepascal.org/view.php?id=35827#c117278 ___ fpc-devel maillist - fpc-devel@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
Re: [fpc-devel] Registers reloading
Hi Marco, That is actually one thing I've been researching myself. Currently the peephole optimiser doesn't have the facilities to detect if a register already contains a value that is being assigned to it, something I call the "Deep Optimizer" but is otherwise just basic data flow analysis. I have been overhauling the peephole optimiser for i386 and x86-64 to be more efficient with fewer passes, although it's taking time to get it into a form that the administrators are happy to merge into the trunk, since it is quite a major change. Yours sincerely, J. Gareth "Kit" Moreton On 18/07/2019 14:33, Marco Borsari via fpc-devel wrote: Hi all, does the compiler have the optimization to avoid reloading into a register of an address (or a value) whether it is already present? I ask this because of this code fragment compiled with the -O4 option: .Lj380: # Register eax allocated # [726] T := T-1; subw $1,2(%ebx) # Register ax released # Register edx allocated # [727] H6 := @STK^[T]; movl U_$GLOBALS_$$_STK,%edx # Register eax allocated movzwl 2(%ebx),%eax leal -8(%edx,%eax,8),%eax # Register edx released movl %eax,-256(%ebp) # [728] H7 := H6; movl %eax,-260(%ebp) <-(1) # Register eax released # [729] Inc(H7, 1); addl $8,-260(%ebp) # Register eax allocated # [730] H6^.I := H6^.I+H7^.I; movl -256(%ebp),%eax <-(2) # Register ecx allocated movswl 4(%eax),%ecx movl -260(%ebp),%eax # Register edx allocated movswl 4(%eax),%edx leal (%ecx,%edx),%eax # Register ecx released movw %ax,%dx movl -256(%ebp),%eax <-(3) movw %dx,4(%eax) # Register eax,dx released In (1) the compiler assumes that eax has the correct address but in (2) does not omit to reload it (eax released too soon). Both seem to be of the same level of the analysis complexity, more deeper should be takes into account of (3) with the use of a supplementar registers as si or di (they are used in other parts of the code). Thank you for any response, Marco Borsari ___ fpc-devel maillist - fpc-devel@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ fpc-devel maillist - fpc-devel@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
[fpc-devel] Registers reloading
Hi all, does the compiler have the optimization to avoid reloading into a register of an address (or a value) whether it is already present? I ask this because of this code fragment compiled with the -O4 option: .Lj380: # Register eax allocated # [726] T := T-1; subw$1,2(%ebx) # Register ax released # Register edx allocated # [727] H6 := @STK^[T]; movlU_$GLOBALS_$$_STK,%edx # Register eax allocated movzwl 2(%ebx),%eax leal-8(%edx,%eax,8),%eax # Register edx released movl%eax,-256(%ebp) # [728] H7 := H6; movl%eax,-260(%ebp) <-(1) # Register eax released # [729] Inc(H7, 1); addl$8,-260(%ebp) # Register eax allocated # [730] H6^.I := H6^.I+H7^.I; movl-256(%ebp),%eax <-(2) # Register ecx allocated movswl 4(%eax),%ecx movl-260(%ebp),%eax # Register edx allocated movswl 4(%eax),%edx leal(%ecx,%edx),%eax # Register ecx released movw%ax,%dx movl-256(%ebp),%eax <-(3) movw%dx,4(%eax) # Register eax,dx released In (1) the compiler assumes that eax has the correct address but in (2) does not omit to reload it (eax released too soon). Both seem to be of the same level of the analysis complexity, more deeper should be takes into account of (3) with the use of a supplementar registers as si or di (they are used in other parts of the code). Thank you for any response, Marco Borsari ___ fpc-devel maillist - fpc-devel@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
