Hi,
I've recently been trying to hand-write code to trigger automatic
vectorization optimizations in GCC on Intel x86 machines (without
using the interfaces in immintrin.h), but I'm running into a problem
where I can't seem to get the concise `vpmovzxbd` or similar
instructions.
My requirement is
Hi Biener,
Thanks for your help!
I have already open a bugreport here
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115252.
Thanks
Hanke Zhang
Richard Biener 于2024年5月27日周一 21:14写道：
>
> On Sat, May 25, 2024 at 3:08 PM Hanke Zhang via Gcc wrote:
> >
> > Hi,
> &g
Hi,
I'm trying to studing the automatic vectorization optimization in GCC,
but I found one case that SLP vectorizer failed to do such things.
Here is the sample code: (also a simplification version of a function
from the 625/525.x264 source code in SPEC CPU 2017)
void pixel_sub_wxh(int16_t
Hi,
I got a question about optimizing function pointers for direct
function calls in C.
Consider the following scenario: one of the fields of a structure is a
function pointer, and all its assignments come from the same function.
Can all its uses be replaced by direct calls to this function? So
.
Maybe I configured vim in some wrong way.
Thanks
Hanke Zhang
Filip Kastl 于2024年4月30日周二 18:00写道：
>
> On Tue 2024-04-30 13:52:16, Hanke Zhang via Gcc wrote:
> > Hi
> > I'm trying to format my code in GCC style.
> >
> > But I don't know how to finish it. I try `inden
Hi
I'm trying to format my code in GCC style.
But I don't know how to finish it. I try `indent` and
`check_GNU_style.sh` in the `contrib` directory. But none of them seem
to work well.
So I wondered is there any official tools to do that?
Thanks
Hanke Zhang
is defined in `config/i386/i386-builtins.h`. And when I try
to include this header file, the error will occur during the
compilation. If you know any way to solve this problem, I would be
very grateful. :)
Thanks
Hanke Zhang
Marc Glisse 于2024年4月9日周二 03:01写道：
>
> On Mon, 8 Apr 2024, Hanke Zhang v
Hi,
I've been working on strengthening auto-vectorization on intel CPUs
recently. I tried to do it in the GIMPLE pass. And I noticed that some
vector types in the GIMPLE code are confusing to me. The example code
is here:
_1 = MEM[(const __m256i_u * {ref-all})_2];
I wondered how I could
Hi,
I'm trying to get the default values for parameters of some functions
in my GIMPLE-PASS. The example code is here:
enum {
edefault1 = 1,
edefault2 = 2,
edefault3 = 3
}
void func(int p0, int p1 = edefault1, int p2 = edefault2, int p3 = edefault3) {
// do other things
}
I want to get
statements may help with it. If there are some more
complex situations, we will give up this optimization.
But I'm more concerned about how to accomplish this.
Thanks
Hanke Zhang
Iain Sandoe 于2024年1月13日周六 17:15写道：
>
>
>
> > On 13 Jan 2024, at 07:45, Hanke Zhang via Gcc wrote:
> >
&
Hi, I'm attempting to compress the size of a field in a structure for
memory-friendly purposes. I created an IPA pass to achieve this, but I
ran into some issues as follows:
// original
struct Foo {
long a1;
int a2;
};
// modified
struct Foo_update {
int a1;
int a2;
};
For the example
Hi Thomas!
Thanks for your reply. That's exactly what I'm missing. When I add
varpool_node::finalize_decl() to my code, everything works fine!
Thomas Schwinge 于2023年12月16日周六 01:15写道：
>
> Hi Hanke!
>
> On 2023-12-13T17:04:57+0800, Hanke Zhang via Gcc wrote:
> > Hi, I'm trying
Hi, I'm trying to create a global variable in my own PASS which
located at the LATE_IPA_PASSES. (I'm using GCC 10.3.0.)
And after creating it, I added the attributes like the following.
// 1. create the var
tree new_name = get_identifier (xx);
tree new_type = build_pointer_type (xx);
tree
Hi, I'm working on loop tiling recently. I want to add this
optimization to GCC. But I have encoutered some problems here and ask
for help.
For the code below as an example:
for (int i = 0; i < 12; i++) {
for (int j = 0; j < arr.length; j++) { // arr.length may be huge
// do something with
Hi, I've been working on vectorization-related optimization lately.
GCC seems to have some optimization vulnerabilities. I would like to
ask if it can be solved.
For example, for the following program using AVX2:
#include
// reg->node2[i].state is an unsigned long long variable
// reg->size is
Hi, I recently ran into an inline-related issue and would like to ask
about it. This is about the ipa-inline.
I'd like to make my function be inlined, but it trapped in the
function 'want_inline_small_function_p', more specificly, in the
conditional statement 'growth_positive_p (callee, e,
Hi
I've been working on function splits recently, and I've noticed that
functions with va_args arguments won't be split, so why is that? I
tried to understand the comments in the source code, but I still don't
get the specific reason.
At the same time, if I do want to split functions with
cc/tree-if-conv.cc:3549
>
> Richard Biener 于2023年10月25日周三 23:40写道：
> >
> >
> >
> > > Am 25.10.2023 um 17:25 schrieb Hanke Zhang via Gcc :
> > >
> > > Hi, I got a gimple relative question.
> > >
> > > I'm trying to replace the
../../gcc/tree-if-conv.cc:3549
Richard Biener 于2023年10月25日周三 23:40写道：
>
>
>
> > Am 25.10.2023 um 17:25 schrieb Hanke Zhang via Gcc :
> >
> > Hi, I got a gimple relative question.
> >
> > I'm trying to replace the .MASK_STORE with a ternary expression in
> &g
Hi, I got a gimple relative question.
I'm trying to replace the .MASK_STORE with a ternary expression in
pass_ifcvt like below:
.MASK_STORE(addr, align, mask, value) => *addr = mask ? value : *addr;
But when I do this, I'm stucked. The addr here is a SSA_NAME of
course. When I try to get the
ss_iv_optimize?
> > >
> > > GCC has the final value replacement pass (pass_scev_cprop) doing these
> > > kind of transforms. Since 'ans' does not have an affine evolution this
> > > case would need to be pattern matched (there are some existing p
replacement pass (pass_scev_cprop) doing these
> kind of transforms. Since 'ans' does not have an affine evolution this
> case would need to be pattern matched (there are some existing pattern
> matchings in the pass).
>
> > Thanks
> > Hanke Zhang
> >
> > Richard
>
> >>> Richard Biener 于2023年10月20日周五 21:33写道：
> >>>>
> >>>>> On Fri, Oct 20, 2023 at 1:48 PM Hanke Zhang via Gcc
> >>>>> wrote:
> >>>>>
> >>>>> Hi, I'm trying to make pass_fre work better
Richard Biener 于2023年10月20日周五 23:27写道：
>
>
>
> > Am 20.10.2023 um 16:33 schrieb Hanke Zhang :
> >
> > Richard Biener 于2023年10月20日周五 21:33写道：
> >>
> >>> On Fri, Oct 20, 2023 at 1:48 PM Hanke Zhang via Gcc
> >>> wrote:
> >>
Richard Biener 于2023年10月20日周五 21:33写道：
>
> On Fri, Oct 20, 2023 at 1:48 PM Hanke Zhang via Gcc wrote:
> >
> > Hi, I'm trying to make pass_fre work better for me. But I got a
> > problem. Like the code below:
> >
> > int glob;
> >
> > void __attribu
Hi, I'm trying to make pass_fre work better for me. But I got a
problem. Like the code below:
int glob;
void __attribute__((oninline))
foo() {
// do nothing meaningful
}
int main() {
if (glob) {
foo();
} else {
// do something that won't change glob
}
if (glob) {
foo();
f I want
to do my own optimization, where should I put it? Put it behind the
pass_iv_optimize?
Thanks
Hanke Zhang
Richard Biener 于2023年10月17日周二 20:00写道：
>
> On Tue, Oct 17, 2023 at 1:54 PM Hanke Zhang wrote:
> >
> > Richard Biener 于2023年10月17日周二 17:26写道：
> > >
> >
Richard Biener 于2023年10月17日周二 17:26写道：
>
> On Thu, Oct 12, 2023 at 2:18 PM Hanke Zhang via Gcc wrote:
> >
> > Hi, I'm recently working on vectorization of GCC. I'm stuck in a small
> > problem and would like to ask for advice.
> >
> > For example, for
Hi, I'm trying to write a pass to erase some useless functions or to
put it another way, detect whether a function is pure or not. (Of
course I know some passes can do the clean after inline)
Here is the problem I got, If a function satisfy the following points,
can it be considered safe to
Hi, I'm working on optimizing if-conversion for my own business
recently. I got a problem here.
I tried to optimize it in such a case, for example, when a conditional
statement block has only if statement and no else statement, the
source C code looks like this:
int* foo; // assume this has been
Hi, I'm recently working on vectorization of GCC. I'm stuck in a small
problem and would like to ask for advice.
For example, for the following code:
int main() {
int size = 1000;
int *foo = malloc(sizeof(int) * size);
int c1 = rand(), t1 = rand();
for (int i = 0; i < size; i++) {
Hi, I've recently been working on static local variables in C. I would
like to ask about some questions about that.
For example, for the following program,
void foo() {
static int x = 0;
x++;
}
int main() {
foo();
}
After optimization with the -O3 -flto option, the entire program will
/show_bug.cgi?id=111672
Richard Biener 于2023年10月4日周三 16:20写道：
>
> On Mon, Oct 2, 2023 at 7:15 PM Hanke Zhang via Gcc wrote:
> >
> > Martin Jambor 于2023年10月3日周二 00:34写道：
> > >
> > > Hello,
> > >
> > > On Mon, Oct 02 2023, Hanke Zhang via Gcc wrote
Richard Biener 于2023年10月4日周三 16:43写道：
>
> On Wed, Oct 4, 2023 at 10:37 AM Richard Biener
> wrote:
> >
> > On Tue, Oct 3, 2023 at 6:30 PM Hanke Zhang via Gcc wrote:
> > >
> > > Hi, I'm a little confused about the behavior of gcc when the function
Hi, I'm a little confused about the behavior of gcc when the function
is not inlined.
Here is an example code:
int __attribute__((noinline)) foo() {
return 1;
}
int main() {
if (foo()) {
printf("foo() returned 1\n");
} else {
printf("foo() returned 0\n");
}
Martin Jambor 于2023年10月3日周二 00:34写道：
>
> Hello,
>
> On Mon, Oct 02 2023, Hanke Zhang via Gcc wrote:
> > Hi, I have some questions about the strategy and behavior of function
> > splitting in gcc, like the following code:
> >
> > int glob;
> > void f()
Hi, I have some questions about the strategy and behavior of function
splitting in gcc, like the following code:
int glob;
void f() {
if (glob) {
printf("short path\n");
return;
}
// do lots of expensive things
// ...
}
I hope it can be broken down like below, so that the whole
Richard Biener 于2023年9月27日周三 15:30写道：
>
> On Wed, Sep 27, 2023 at 7:21 AM Hanke Zhang via Gcc wrote:
> >
> > Thanks! I understand what you mean, then can I think that if the
> > function here is not an external function, but a function visible to
> > the compiler a
Hi, I have recently been working on issues related to the changing
values of global variables. That is, I was trying to develop a gimple
pass, which needs to check whether the value of a global variable is
modified in the a function or some blocks.
Some of the more tricky cases are as follows:
Thanks! I understand what you mean, then can I think that if the
function here is not an external function, but a function visible to
the compiler and the function doesn't modify `a`, then these two
blocks can be merged?
Marc Glisse 于2023年9月27日周三 12:51写道：
>
> On Wed, 27 Sep 2023, Hanke Zha
Hi, I have recently been working on merging if-else statement blocks,
and I found a rather bizarre phenomenon that I would like to ask
about.
A rough explanation is that for two consecutive if-else blocks, if
their if statements are exactly the same, they should be merged, like
the following
Richard Biener 于2023年9月25日周一 13:46写道：
>
>
>
> > Am 25.09.2023 um 04:53 schrieb Hanke Zhang via Gcc :
> >
> > Hi, I have recently been working on loops in gcc, and I have some
> > questions about the loop traversal.
> >
> > I use loops_list(cfun, L
Hi, I have recently been working on loops in gcc, and I have some
questions about the loop traversal.
I use loops_list(cfun, LI_ONLY_INNERMOST) to traverse the loops in my
pass to obtain the loop.
I found that the order of traversal and the order of actual
instruction execution will be
Hi, I have been very interested in loop fusion recently. I found that
both LLVM and icc have implemented this optimization. I also noticed
that gcc does not seem to implement it.
I would like to ask if gcc have any plans to implement this
optimization? In addition, I also found that there is a
Thanks! That works!
Richard Biener 于2023年9月18日周一 15:56写道：
>
> On Mon, Sep 18, 2023 at 9:17 AM Hanke Zhang via Gcc wrote:
> >
> > Hi, I am currently developing a new pass in the late_ipa_passes phase,
> > located behind the pass_ipa_pta and in front of the
> > p
Hi, I am currently developing a new pass in the late_ipa_passes phase,
located behind the pass_ipa_pta and in front of the
pass_omp_simd_clone. I now hope that after the pass I developed, the
code can be vectorized, that is, the code that can be vectorized
during the pass_omp_simd_clone.
But not
I get it. It's a `lto` problem. If I remove `-flto`, both work.
Thanks for your help again!
Richard Biener 于2023年9月15日周五 21:13写道：
>
> On Fri, Sep 15, 2023 at 3:09 PM Hanke Zhang wrote:
> >
> > Richard Biener 于2023年9月15日周五 19:59写道：
> >
> > >
> > > O
Richard Biener 于2023年9月15日周五 19:59写道：
>
> On Fri, Sep 15, 2023 at 1:21 PM Hanke Zhang via Gcc wrote:
> >
> > Hi I'm trying to accelerate my program with -ftree-vectorize and
> > -ftree-parallelize-loops.
> >
> > Here are my test results using the different o
Hi I'm trying to accelerate my program with -ftree-vectorize and
-ftree-parallelize-loops.
Here are my test results using the different options (based on
gcc10.3.0 on i9-12900KF):
gcc-10 test.c -O3 -flto
> time: 29000 ms
gcc-10 test.c -O3 -flto -mavx2 -ftree-vectorize
> time: 17000 ms
gcc-10
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