search for: bcmp

If we are considering an optimization to convert calls to memcmp into bcmp, then does it make sense to add an intrinsic for bcmp like there is for memcmp? That way IR writers can express their requirements precisely: memcmp if you care about the direction of inequality, and bcmp if you do not. On Fri, Jan 4, 2019 at 12:34 PM James Y Knight via llvm-dev < llvm-dev at...

...M Clement Courbet <courbet at google.com> wrote: > On Fri, Jan 4, 2019 at 12:34 PM James Y Knight via llvm-dev < >> llvm-dev at lists.llvm.org> wrote: >> >>> This seems a somewhat odd and overcomplicated way to go about this. >>> >>> Given that bcmp was required in POSIX until relatively recently, I will >>> guess that almost all platforms support it already. From a quick check, >>> glibc, freebsd, netbsd, newlib, and musl all seem to contain it. So, >>> couldn't we just add bcmp to the runtime function list for...

...? >>> >> >> Even so, it should be fine to enable it for those platforms which do >> include it. >> >> I do note, sadly, that currently out of all these implementations, only >>>> NetBSD and FreeBSD seem to actually define a separate more optimized bcmp >>>> function. That does mean that this optimization would be effectively a >>>> no-op, for the vast majority of people. >>>> >>> >>> This might or might not be considered really an issue. >>> >> >> Right, the issue is addin...

...; and "generally": what about users who don't ? > Even so, it should be fine to enable it for those platforms which do include it. I do note, sadly, that currently out of all these implementations, only >> NetBSD and FreeBSD seem to actually define a separate more optimized bcmp >> function. That does mean that this optimization would be effectively a >> no-op, for the vast majority of people. >> > > This might or might not be considered really an issue. > Right, the issue is adding an effectively useless optimization in llvm. - In my original...

...very large improvement of this approach on our internal codebase. A significant portion of this improvement comes from the stl, typically `std::string::operator==()`. Note that this is a *backend-only change*. Because the c family of languages do not have a standard `memeq()` (posix used to have `bcmp()` but it was removed in 2001), c/c++ code cannot communicate the equality comparison semantics to the compiler. We did not add an RTLIB entry for memeq because the user environment is not guaranteed to contain a `memeq()` function as the libc has no such concept. If there is interest, we could a...

Clang doesn't have a suitable replacement for libgcc readily available. Supply one that we know exists. Use "-fno-builtin-bcmp" to prevent clang from calling a function that doesn't exist. Signed-off-by: Bill Wendling <morbo at google.com> --- scripts/Kbuild.klibc | 2 ++ usr/klibc/arch/x86_64/MCONFIG | 2 ++ 2 files changed, 4 insertions(+) diff --git a/scripts/Kbuild.klibc b/scripts/Kbuild.klib...

...85bfd6 100644 --- a/usr/klibc/arch/x86_64/MCONFIG +++ b/usr/klibc/arch/x86_64/MCONFIG @@ -27,7 +27,7 @@ ifneq ($(cc-name),clang) # so we can't use a cc-option test to filter them. KLIBCOPTFLAGS += -falign-functions=1 -falign-jumps=1 -falign-loops=1 else -KLIBCOPTFLAGS += -fno-builtin-bcmp +KLIBCOPTFLAGS += -fno-builtin-bcmp -fcommon endif KLIBCBITSIZE = 64 -- 2.26.0.rc2.310.g2932bb562d-goog

...g the proper compiler name or "cc-option". - Added "-Werror" to "cc-option" to catch flags that cause warnings. - Retain "-nostdinc -iwithprefix include" and use the proper clang flag to get the path to find "stdarg.h". - Move "-fno-builtin-bcmp" to KLIBCREQFLAGS in scripts/Kbuild.klibc. Bill Wendling (4): [klibc] Kbuild: add support for clang builds [klibc] Kbuild: support clang's lld [klibc] Kbuild: Add "-fcommon" for clang builds [klibc] Clean up clang warnings Makefile | 3 +++ scrip...

Hi, Lately, I have been wondering how a compiler like GCC or Clang implements builtin functions like sqrt, sin, and also more bit-specific things like bcmp and ffs. Originially, these were all deferred to the C library where they might still have a "backup implementation", but I don't understand why a compiler would choose the non-builtin version, as it should know its version is faster (or that's the way it should be at least). -...

...issing something. I hesitate to submit this as a bug, since technically I guess you could say that blank names, especially duplicates, are not kosher. But on the other hand, this combinatorial behaviour seems to occur only for blanks. -Frank PhD, Computational Biologist, Harvard Medical School BCMP/SGM-322, 250 Longwood Ave, Boston MA 02115, USA. Tel: 617-432-3555 Fax: 617-432-3557 http://llama.med.harvard.edu/~fgibbons

This is a series of patches for clang compatibility: - Using flags needed flags and removing unsupported flags. - Adding support for clang's LLD linker. - Removing a variety of warnings. Bill Wendling (3): [klibc] Kbuild: use "libc.a" with clang [klibc] Kbuild: Add "-fcommon" for clang builds [klibc] Clean up clang warnings Michael Davidson (1): [klibc] Kbuild:

On Fri, 2020-03-27 at 15:29 -0700, Bill Wendling wrote: > Clang doesn't have a suitable replacement for libgcc readily available. > Supply one that we know exists. Use "-fno-builtin-bcmp" to prevent clang > from calling a function that doesn't exist. Doesn't this contradict the comment added for KLIBCLIBGCC_DEF? > Signed-off-by: Bill Wendling <morbo at google.com> > --- > scripts/Kbuild.klibc | 2 ++ > usr/klibc/arch/x86_64/MCONFIG | 2...

...would be). Can anyone give me pointers on where to look for more info. I've had a look in the places I could think of (plot.lm.R, termplot.R, plot.R, aov.R), and couldn't find anything. Maybe I overlooked it? Thanks -Frank Gibbons PhD, Computational Biologist, Harvard Medical School BCMP/SGM-322, 250 Longwood Ave, Boston MA 02115, USA. Tel: 617-432-3555 Fax: 617-432-3557 http://llama.med.harvard.edu/~fgibbons

Le 20 janv. 2012 à 14:38, Ruben Van Boxem a écrit : > Hi, > > Lately, I have been wondering how a compiler like GCC or Clang implements builtin functions like sqrt, sin, and also more bit-specific things like bcmp and ffs. Originially, these were all deferred to the C library where they might still have a "backup implementation", but I don't understand why a compiler would choose the non-builtin version, as it should know its version is faster (or that's the way it should be at least). >...

...in the past, but it was never really answered by anyone who was familiar with R/S-PLUS. Can anyone help me with this? I guess I'm really wondering how R is computing the constant term in its discriminant function. Thanks, -Frank Gibbons PhD, Computational Biologist, Harvard Medical School BCMP/SGM-322, 250 Longwood Ave, Boston MA 02115, USA. Tel: 617-432-3555 Fax: 617-432-3557 http://llama.med.harvard.edu/~fgibbons

...error message. I'd really appreciate any suggestions for this problem. I've scoured the web, and haven't been able to find any examples in which an add-on package function is called using the RSPerl module. Thanks, Frank Gibbons PhD, Computational Biologist, Harvard Medical School BCMP/SGM-322, 250 Longwood Ave, Boston MA 02115, USA. Tel: 617-432-3555 Fax: 617-432-3557 http://llama.med.harvard.edu/~fgibbons -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send...

Add cc-name to klibc/scripts/Kbuild.include. Make optimization flags not supported by clang conditional on cc-name. Use "--print-file-name=include" and "--print-libgcc-file-name" when using clang. Use cc-option to enable compiler-specific flags. Mark "bcmp" as not a builtin to prevent clang from using it. Signed-off-by: Bill Wendling <morbo at google.com> --- scripts/Kbuild.include | 8 ++++++-- scripts/Kbuild.klibc | 13 +++++++++---- usr/klibc/Kbuild | 4 ++-- usr/klibc/arch/x86_64/MCONFIG | 6 ++++-- 4...

...for clang builds Add cc-name to klibc/scripts/Kbuild.include. Make optimization flags not supported by clang conditional on cc-name. Use "--print-file-name=include" and "--print-libgcc-file-name" when using clang. Use cc-option to enable compiler-specific flags. Mark "bcmp" as not a builtin to prevent clang from using it. Signed-off-by: Bill Wendling <morbo at google.com> Signed-off-by: Ben Hutchings <ben at decadent.org.uk> --- scripts/Kbuild.include | 8 ++++++-- scripts/Kbuild.klibc | 13 +++++++++---- usr/klibc/Kbuild...

...-option". > > - Added "-Werror" to "cc-option" to catch flags that cause warnings. > > - Retain "-nostdinc -iwithprefix include" and use the proper clang flag > > to get the path to find "stdarg.h". > > - Move "-fno-builtin-bcmp" to KLIBCREQFLAGS in scripts/Kbuild.klibc. > > I'm just going to apply this series now, and we can worry about > cleaning up the FLAGS variable definitions later. > > Thanks for your patience, [...] Unfortunately this doesn't work with Clang and lld 9.0.1. Clang is n...

...of this approach on our internal > codebase. A significant portion of this improvement comes from the stl, > typically `std::string::operator==()`. > > Note that this is a *backend-only change*. Because the c family of > languages do not have a standard `memeq()` (posix used to have `bcmp()` but > it was removed in 2001), c/c++ code cannot communicate the equality > comparison semantics to the compiler. > > We did not add an RTLIB entry for memeq because the user environment is > not guaranteed to contain a `memeq()` function as the libc has no such > concept. >...