Hey,
On Thu, 10 Aug 2023, Martin Uecker wrote:
> > offset(struct foo_flex, t[0]) + N * sizeof(foo->t);
> >
> > With GCC, offset(struct foo_flex,t[0]) == 6, which is also correct.
>
> This formula might be considered incorrect / dangerous because
> it might allocate less storage than sizeof(str
Hello,
On Wed, 9 Aug 2023, Qing Zhao wrote:
> > So, should the equivalent FAM struct also have this sizeof()? If no:
> > there should be a good argument why it shouldn't be similar to the non-FAM
> > one.
>
> The sizeof() of a structure with FAM is defined as: (after I searched online,
> I t
Hello,
On Wed, 9 Aug 2023, Qing Zhao wrote:
> Although this is an old FAM related issue that does not relate to my current
> patch
> (and might need to be resolved in a separate patch). I think that it’s
> necessary to have
> more discussion on this old issue and resolve it.
>
> The first t
Hello,
On Wed, 9 Aug 2023, Zhang, Annita via Gcc-patches wrote:
> > The question is whether you want to mandate the 16-bit floating point
> > extensions. You might get better adoption if you stay compatible with
> > shipping
> > CPUs. Furthermore, the 256-bit tuning apparently benefits current
Hello,
On Tue, 8 Aug 2023, Martin Uecker via Gcc-patches wrote:
> There at least three different size expression which could
> make sense. Consider
>
> short foo { int a; short b; char t[]; };
>
> Most people seem to use
>
> sizeof(struct foo) + N * sizeof(foo->t);
>
> which for N == 3 yield
Hello,
On Tue, 8 Aug 2023, Jakub Jelinek via Gcc-patches wrote:
> What I'd really like to avoid is having all compiler bugs (primarily ICEs)
> considered to be security bugs (e.g. DoS category), it would be terrible to
> release every week a new compiler because of the "security" issues.
> Runnin
Hello,
On Tue, 1 Aug 2023, Joseph Myers wrote:
> > Only because cmpxchg is defined in terms of memcpy/memcmp. If it were
> > defined in terms of the == operator (obviously applied recursively
> > member-wise for structs) and simple-assignment that wouldn't be a problem.
>
> It also wouldn't
Hello,
On Mon, 31 Jul 2023, Martin Uecker wrote:
> > Say you have a loop like so:
> >
> > _Atomic T obj;
> > ...
> > T expected1, expected2, newval;
> > newval = ...;
> > expected1 = ...;
> > do {
> > expected2 = expected1;
> > if (atomic_compare_exchange_weak(&obj, &expected2, newval);
> >
Hello,
On Fri, 28 Jul 2023, Martin Uecker wrote:
> > > Sorry, somehow I must be missing something here.
> > >
> > > If you add something you would create a new value and this may (in
> > > an object) have random new padding. But the "expected" value should
> > > be updated by a failed atomic_co
Hello,
On Mon, 17 Jul 2023, Richard Sandiford via Gcc-patches wrote:
> >> There are some existing attributes that similarly affect semantics
> >> in ways that cannot be ignored. vector_size is one obvious example.
> >> But that doesn't make it a good thing. :)
> >...
> > If you had added __arm(b
Hey,
On Tue, 11 Jul 2023, Alexander Monakov via Gcc-patches wrote:
> > > > * nosseclobber: claims (and ensures) that xmm8-15 aren't clobbered
> > >
> > > This is the weak/active form; I'd suggest "preserve_high_sse".
> >
> > But it preserves only the low parts :-) You swapped the two in your
Hello,
On Mon, 10 Jul 2023, Alexander Monakov wrote:
> I think the main question is why you're going with this (weak) form
> instead of the (strong) form "may only clobber the low XMM regs":
I want to provide both. One of them allows more arbitrary function
definitions, the other allows more r
Hello,
On Tue, 11 Jul 2023, Jan Hubicka wrote:
> > > > When a function doesn't contain calls to
> > > > unknown functions we can be a bit more lenient: we can make it so that
> > > > GCC simply doesn't touch xmm8-15 at all, then no save/restore is
> > > > necessary.
>
> One may also take into ac
Hello,
the ELF psABI for x86-64 doesn't have any callee-saved SSE
registers (there were actual reasons for that, but those don't
matter anymore). This starts to hurt some uses, as it means that
as soon as you have a call (say to memmove/memcpy, even if
implicit as libcall) in a loop that manipula
Hello,
On Thu, 27 Apr 2023, Jakub Jelinek wrote:
> The first really large error I see is for sinl with
> x/2gx &val
> 0x748160ed90d9425b0xefd8b811d6293294
> i.e.
> 1.5926552660973502228303666578452949e+253
> with most significant double being
> 1.5926552660973502e+253
> and low double
> -5.99
Hello,
On Wed, 26 Apr 2023, Jakub Jelinek via Gcc-patches wrote:
> For glibc I've gathered data from:
> 4) using attached ulp-tester.c (how to invoke in file comment; tested
>both x86_64, ppc64, ppc64le 50M pseudo-random values in all 4 rounding
>modes, plus on x86_64 float/double sin/cos
Hello,
On Wed, 18 Jan 2023, Jakub Jelinek wrote:
> > > > > Partly OT, what is riscv not defaulting that on as well? Does it have
> > > > > usable unwind info even without that option, something else?
> > > >
> > > > The RISC-V ABI does not address this, AFAICS.
> > >
> > > And neither do many
Hello,
On Wed, 18 Jan 2023, Jakub Jelinek wrote:
> On Wed, Jan 18, 2023 at 04:09:08PM +0100, Andreas Schwab wrote:
> > On Jan 18 2023, Jakub Jelinek wrote:
> >
> > > Partly OT, what is riscv not defaulting that on as well? Does it have
> > > usable unwind info even without that option, somethin
On Wed, 18 Jan 2023, Andreas Schwab via Gcc-patches wrote:
> No unwind tables are generated, as if -funwind-tables is ignored. If
> LTO is disabled, everything works as expected.
On Risc-V btw. (which, unlike i386,aarch64,s390,rs6000 does not
effectively enable funwind-tables always via either
Hello,
On Thu, 10 Nov 2022, Martin Liška wrote:
> > These changes are part of
> > commit r13-2361-g7e0db0cdf01e9c885a29cb37415f5bc00d90c029
> > "STABS: remove -gstabs and -gxcoff functionality". What this does is
> > remove these identifiers from "poisoning":
> >
> > /* As the last action
Hello,
On Thu, 10 Nov 2022, Martin Liška wrote:
> This is a patch which adds support for Sphinx in lib*/Makefile.am where
> I wrongly modified Makefile.in that are generated.
>
> One thing that's missing is that the generated Makefile.in does not
> contain 'install-info-am' target and thus the c
Hello,
On Wed, 9 Nov 2022, Martin Liška wrote:
> I think we should remove documentation for unsupported GCC releases
> as it's indexed by Google engine. Second reason is that the page is long
> one one can't easily jump to Current development documentation.
>
> Thoughts?
I think everything that
Hey,
On Thu, 20 Oct 2022, Thomas Schwinge wrote:
> This had been done in
> wwwdocs commit 5c7ecfb5627e412a3d142d8dc212f4cd39b3b73f
> "Document deprecation of OpenMP MIC offloading in GCC 12".
>
> I'm sad about this, because -- in theory -- such a plugin is very useful
> for offloading simulation
Hello,
On Tue, 11 Oct 2022, Jørgen Kvalsvik wrote:
> I apologise for the confusion. The diff there is not a part of the
> change itself (note the indentation) but rather a way to reproduce,
Ah! Thanks, that explains it, sorry for adding confusion on top :-)
Ciao,
Michael.
Hello,
On Tue, 11 Oct 2022, Jørgen Kvalsvik via Gcc-patches wrote:
> The coverage support will under some conditions decide to split edges to
> accurately report coverage. By running the test suite with/without this
> edge splitting a small diff shows up, addressed by this patch, which
> should c
Hello,
On Tue, 20 Sep 2022, Aldy Hernandez wrote:
> > FWIW, in IEEE, 'abs' (like 'copy, 'copysign' and 'negate') are not
> > arithmetic, they are quiet-computational. Hence they don't rise
> > anything, not even for sNaNs; they copy the input bits and appropriately
> > modify the bit pattern acc
Hello,
On Mon, 19 Sep 2022, Richard Biener via Gcc-patches wrote:
> > but I guess it's good we do the right thing for correctness sake, and
> > if it ever gets used by someone else.
> >
> > >
> > > That said, 'set_nonnegative' could be interpreted to be without
> > > NaNs?
> >
> > Sounds good to
Hello,
okay, I'll bite :) DBG_REGISTER_NUMBER? DEBUGGER_REGNO?
Ciao,
Michael.
Hello,
On Wed, 3 Aug 2022, Jeff Law via Gcc-patches wrote:
> > .optimized dump shows:
> >_1 = ABS_EXPR ;
> >_3 = _1 & 1;
> >return _3;
> >
> > altho combine simplifies it to x & 1 on RTL, resulting in code-gen:
> > f1:
> > and w0, w0, 1
> > ret
> Doesn't the abs
Hello,
On Wed, 25 May 2022, Richard Biener via Gcc-patches wrote:
> I guess we might want to (warn about labels in the "toplevel"
> scope in switch statements). So warn about
>
> switch (x)
> {
> case 1:
> bar:
> };
That style is actually used quite some time in GCC itself. Sometimes with
st
Hello,
On Wed, 13 Apr 2022, Roger Sayle wrote:
> The x86 instruction encoding for SImode andn is longer than the
> equivalent notl/andl sequence when the source for the not operand
> is the same register as the destination.
_And_ when no REX prefixes are necessary for the notl,andn, which they a
Hi,
On Thu, 10 Feb 2022, Richard Biener via Gcc-patches wrote:
> On Wed, Feb 9, 2022 at 2:21 PM Thomas Schwinge
> wrote:
> >
> > Hi!
> >
> > OK to push (now, or in next development stage 1?) the attached
> > "Consider 'TDF_UID', 'TDF_NOUID' in 'print_node_brief', 'print_node'",
> > or should th
Hello,
On Wed, 9 Feb 2022, Richard Biener wrote:
> > That breaks down when a birth is there (because it was otherwise
> > reachable) but not on the taken path:
> >
> > if (nevertrue)
> > goto start;
> > goto forw;
> > start:
> > {
> > int i;
> > printf("not really reachable,
Hey,
On Tue, 8 Feb 2022, Joseph Myers wrote:
> On Tue, 8 Feb 2022, Richard Biener via Gcc-patches wrote:
>
> > which I think is OK? That is, when the abstract machine
> > arrives at 'int i;' then the previous content in 'i' goes
> > away? Or would
>
> Yes, that's correct. "If an initializati
Hello,
On Tue, 8 Feb 2022, Richard Biener wrote:
> > int state = 2, *p, camefrom1 = 0;
> > for (;;) switch (state) {
> > case 1:
> > case 2: ;
> > int i;
> > if (state != 1) { p = &i; i = 0; }
> > if (state == 1) { (*p)++; return *p; }
> > state = 1;
> > continue;
> > }
>
Hello,
On Tue, 8 Feb 2022, Richard Biener wrote:
> int foo(int always_true_at_runtime)
> {
> {
> int *p;
> if (always_true_at_runtime)
> goto after;
> lab:
> return *p;
> after:
> int i = 0;
> p = &i;
> if (always_true_at_runtime)
> goto lab;
> }
> return
Hello,
On Thu, 3 Feb 2022, Richard Biener via Gcc-patches wrote:
> /* Preserve explicit divisions by 0: the C++ front-end wants to detect
>undefined behavior in constexpr evaluation, and assuming that the
> division
>traps enables better optimizations than these anyway. */
> (for div (t
Hello,
On Thu, 3 Feb 2022, Richard Biener via Gcc-patches wrote:
> > > It indeed did occur to me as well, so as we're two now I tried to
> > > see how it looks like. It does like the following (didn't bother to
> > > replace all build_clobber calls but defaulted the parameter - there
> > > ar
Hello,
On Thu, 3 Feb 2022, Richard Biener wrote:
> > > This adds a flag to CONSTRUCTOR nodes indicating that for clobbers this
> > > marks the end-of-life of storage as opposed to just ending the lifetime
> > > of the object that occupied it. The dangling pointer diagnostics uses
> > > CLOBBER
Hello,
On Wed, 2 Feb 2022, Richard Biener via Gcc-patches wrote:
> This adds a flag to CONSTRUCTOR nodes indicating that for clobbers this
> marks the end-of-life of storage as opposed to just ending the lifetime
> of the object that occupied it. The dangling pointer diagnostics uses
> CLOBBER
Hello,
On Mon, 20 Dec 2021, Uros Bizjak wrote:
> > Thanks.
> > I see nobody commented on Micha's post there.
> >
> > Here is a patch that implements it in GCC, i.e. C++ doesn't change ABI (at
> > least
> > not from the past few releases) and C does for GCC:
> >
> > 2021-12-15 Jakub Jelinek
>
Hello,
On Thu, 25 Nov 2021, Richard Biener via Gcc-patches wrote:
> It seems to be a style to place gcc_unreachable () after a
> switch that handles all cases with every case returning.
> Those are unreachable (well, yes!), so they will be elided
> at CFG construction time and the middle-end will
Hello,
On Thu, 25 Nov 2021, Richard Biener wrote:
> > Yes, that's definitely the case - I was too lazy to re-use the old
> > option name here. But I don't have a good name at hand, maybe clang
> > has an option covering the cases I'm thinking about.
As you asked: I already have difficulties to
Hello,
On Wed, 24 Nov 2021, Richard Biener wrote:
> >> +/* Unreachable code in if (0) block. */
> >> +void baz(int *p)
> >> +{
> >> + if (0)
> >> + {
> >> +return; /* { dg-bogus "not reachable" } */
> >
> >Hmm? Why are you explicitely saying that warning here would be bogus?
>
Hello,
> +/* Unreachable code in if (0) block. */
> +void baz(int *p)
> +{
> + if (0)
> + {
> +return; /* { dg-bogus "not reachable" } */
Hmm? Why are you explicitely saying that warning here would be bogus? It
quite clearly _is_ unreachable, so warning there makes sense. Mayb
Hello,
On Mon, 18 Oct 2021, Richard Sandiford wrote:
> > (It's a really cute hack that works as a micro optimization, the question
> > is, do we really need to go there already, are all other less hacky
> > approaches not bringing similar improvements? The cuter the hacks the
> > less often t
Hello,
On Thu, 14 Oct 2021, Richard Biener via Gcc-patches wrote:
> > I have bisected an AMD zen2 10% performance regression of SPEC 2006 FP
> > 433.milc bechmark when compiled with -Ofast -march=native -flto to this
> > commit. See also:
> >
> >
> > https://lnt.opensuse.org/db_default/v4/SP
Hello,
On Thu, 14 Oct 2021, Richard Biener wrote:
> > So, at _this_ write-through of the email I think I like the above idea
> > best: make ao_ref be a tree (at least its storage, because it currently
> > is a one-member-function class), make ao_ref.volatile_p be
> > tree_base.volatile_flag (h
Hello,
[this is the fourth attempt to write a comment/review/opinion for this
ao_ref-in-tcc_reference, please accept some possible incoherence]
On Tue, 12 Oct 2021, Richard Biener via Gcc-patches wrote:
> This prototype hack introduces a new tcc_reference TREE_AOREFWRAP
> which we can use to wr
Hello,
On Sat, 9 Oct 2021, apinski--- via Gcc-patches wrote:
> + (lshift (convert (convert:boolean_type_node @0)) { shift; })))
> +/* a ? -1 : 0 -> -a. No need to check the TYPE_PRECISION not being 1
> + here as the powerof2cst case above will handle that case correctly.
> */
W
Hello,
On Tue, 5 Oct 2021, Richard Biener wrote:
> > First notice that this doesn't have an empty latch block to start with
> > (in fact, there is no separate latch block at all), so the loop
> > optimizers haven't been initialized for simple latches at this point.
> > Still, I would say that
Hello,
On Mon, 4 Oct 2021, Jeff Law wrote:
> And just in case it got lost. Here's the analysis on 960218-1 on visium:
>
> We've got this going into ethread:
>
> int f (int x)
> {
> int D.1420;
> int a;
>
> ;; basic block 2, loop depth 0, maybe hot
> ;; prev block 0, next block 3, fla
Hello,
On Thu, 16 Sep 2021, Richard Biener via Gcc-patches wrote:
> > Typically for the native_interpret/native_encode we punt if
> > BITS_PER_UNIT != 8 || CHAR_BIT != 8 because nobody had the energy to
> > deal with the weird platforms (especially if we have currently none, I
> > believe dsp1
Hello,
On Mon, 13 Sep 2021, Aldy Hernandez via Gcc-patches wrote:
The testcase still tests what it's supposed to test with ...
> > typedef unsigned short uint16_t;
> >
> > uint16_t a, b;
> >
> > int *j_global;
> > uint16_t f(void)
> > {
> >int c, **p;
> >short d = 2, e = 4;
> >
... "c =
Hello,
On Mon, 13 Sep 2021, Jeff Law via Gcc-patches wrote:
> > So it looks like there's some undefined behavior going on, even before
> > my patch. I'd like to get some feedback, because this is usually the
> > type of problems I see in the presence of a smarter threader... things
> > get shuff
Hello,
On Fri, 10 Sep 2021, Richard Biener via Gcc-patches wrote:
> diagnostic from the Ada frontend. The warnings are pruned from the
> testsuite output via prune_gcc_output but somehow this doesn't work
> for the tests in gfortran.dg/debug which are now failing with excess
> errors. That seem
Hello,
On Fri, 10 Sep 2021, Aldy Hernandez via Gcc-patches wrote:
> Like this?
Yep, but I can't approve.
Ciao,
Michael.
Hi,
On Fri, 10 Sep 2021, Aldy Hernandez via Gcc-patches wrote:
> }
> +
> + /* Threading through a non-empty latch would cause code to be added
"through an *empty* latch". The test in code is correct, though.
And for the before/after loops flag you added: we have a
cfun->curr_properties
Hello,
On Tue, 10 Aug 2021, Jakub Jelinek via Gcc-patches wrote:
> > +# Place ISO_Fortran_binding.h also under include/ in the build directory
> > such
> > +# that it can be used for in-built-tree testsuite runs without
> > interference of
> > +# other files in the build dir - like intrinsic .m
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