Displaying 20 results from an estimated 3000 matches similar to: "[LLVMdev] -O4 limitations in llvm/llvm-gcc-4.2 2.5?"
2009 Jan 25
0
[LLVMdev] -O4 limitations in llvm/llvm-gcc-4.2 2.5?
Jack Howarth wrote:
> I've had better luck compiling all of pymol 1.1r2 with
> -O4 on darwin9. Everythink links and there appears to be
> no regressions in the resulting code. I take it that LTO
> in llvm 2.5 is still limited to dead code elimination,
> correct?
No.
libLTO does the equivalent to opt -internalize -ipsccp -globalopt
-constmerge -deadargelim -instcombine
2015 May 11
2
[LLVMdev] about MemoryDependenceAnalysis usage
add -basicaa to your command line :)
On Mon, May 11, 2015 at 7:15 AM, Willy WOLFF <willy.mh.wolff at gmail.com> wrote:
> I play a bit more with MemoryDependenceAnalysis by wrapping my pass, and
> call explicitely BasicAliasAnalysis. Its still using No Alias Analysis.
>
> How can I let MemoryDependenceAnalysis use BasicAliasAnalysis?
>
> Please, find attached my pass.
>
2011 Dec 30
1
[LLVMdev] Safe Passes
Which transformation passes are 'safe', meaning it does not worsens the
effectiveness of a later pass or the generated code? I imagine all
passes which either removes data or add attributes are included in this
list, plus some simplification passes:
-adce
-argpromotion
-constmerge
-constprop
-deadargelim
-dse
-functionattrs
-globaldce
-globalopt
-gvn
-instcombine
-internalize
2015 Jan 17
3
[LLVMdev] loop multiversioning
Does LLVM have loop multiversioning ? it seems it does not with clang++ -O3
-mllvm -debug-pass=Arguments program.c -c
bash-4.1$ clang++ -O3 -mllvm -debug-pass=Arguments fast_algorithms.c -c
clang-3.6: warning: treating 'c' input as 'c++' when in C++ mode, this
behavior is deprecated
Pass Arguments: -datalayout -notti -basictti -x86tti -targetlibinfo -no-aa
-tbaa -scoped-noalias
2013 Aug 19
1
[LLVMdev] How to disbale loop-rotate in opt -O3 ?
Hello,
I am trying to simplify the CFG of a given code and eliminate the conditionals, even though I will obtain codes that are not semantically equivalent.
For example, given a simple loop:
for(i=0; i<N; i++){
a[i] = i;
if (i%2==0)
a[i] += 12;
}
I would keep only the loop, without the if statement:
for(i=0; i<N; i++){
a[i] = i;
}
I can eliminate such conditionals on
2007 May 18
0
[LLVMdev] API changes (was Antw.: 2.0 Pre-release tarballs online)
On Sat, 19 May 2007, Anton Korobeynikov wrote:
>> * It seems that a C-call like printf("---\n") is transformed to puts
>> ("---") in the LLVM IR instead of keeping it a printf. What are the
>> circumstances in which this happens? Do other similar conversions
>> occur? Can this be turned off (lower optimisation level?)? Manually
>> replacing the
2015 May 09
2
[LLVMdev] about MemoryDependenceAnalysis usage
Hi,
I try to use MemoryDependenceAnalysis in a pass to analyse a simple function:
void fct (int *restrict*restrict M, int *restrict*restrict L) {
S1: M[1][1] = 1;
S2: L[2][2] = 2;
}
When I iterate over MemoryDependenceAnalysis on the S2 statement, I get the load instruction for the first depth of the array, that’s ok. But I get also the load and store for the S1 statement.
I assume the
2007 May 23
1
[LLVMdev] API changes (was Antw.: 2.0 Pre-release tarballs online)
On Tue, 22 May 2007 23:52:46 -0700 (PDT)
Chris Lattner <sabre at nondot.org> wrote:
>On Sun, 20 May 2007, Bram Adams wrote:
>> On a related note: while using llvmc I have some test cases where the
>> following error now pops up on Linux X86 (not on OSX):
>>
>> <premain>: CommandLine Error: Argument 'debug' defined more than once!
>> llvmc:
2007 May 18
1
[LLVMdev] API changes (was Antw.: 2.0 Pre-release tarballs online)
Hello, Bram
> * It seems that a C-call like printf("---\n") is transformed to puts
> ("---") in the LLVM IR instead of keeping it a printf. What are the
> circumstances in which this happens? Do other similar conversions
> occur? Can this be turned off (lower optimisation level?)? Manually
> replacing the puts-calls by a printf-call is not
2016 May 09
4
Some questions about phase ordering in OPT and LLC
Hi,
I'm a PhD student doing phase ordering as part of my PhD topic and I
would like to ask some questions about LLVM.
Executing the following command to see what passes does OPT execute when
targeting a SPARC V8 processor:
/opt/clang+llvm-3.7.1-x86_64-linux-gnu-ubuntu-15.10/bin/llvm-as <
/dev/null | /opt/clang+llvm-3.7.1-x86_64-linux-gnu-ubuntu-15.10/bin/opt
-O3 -march=sparc -mcpu=v8
2012 Jun 08
2
[LLVMdev] How to use LLVM optimizations with clang
Hi,
> If I compile the program using the following command line i.e.
>
> $ clang -O3 -lm *.c
this may be doing link time optimization.
>
> then
>
> $ time ./a.out
>
> real 0m2.606s
> user 0m2.584s
> sys 0m0.012s
>
> BUT, if I use all the optimizations enabled with -O3 but specify them
> explicity i.e.
you can just use "opt -O3"
2012 Jun 08
2
[LLVMdev] How to use LLVM optimizations with clang
Hi,
> I tried it with -o - but its producing an error
>
> gcc: fatal error: cannot specify -o with -c, -S or -E with multiple files
>
> What you suggest?
what I wrote:
>> for F in *.c ; do B=`basename $F .c` ; gcc -fplugin=/path/to/dragonegg.so
>> -S -o - $F -fplugin-arg-dragonegg-emit-ir | opt -adce -o $B.ll ; done
>> clang *.ll
Thanks to the for loop and
2015 Jan 05
2
[LLVMdev] LTO v. opt
Thanks to you both.
On my Linux (centos6) system, I have reproduce a variant of the bug and learned about
-plugin-opt=-debug-pass=Arguments
which I infer from comments is intended to built arguments to “opt” however I found that some of the arguments don’t seem to be quite correct. I assume this just minor bit rot.
bin/opt -o pass1.bc -datalayout -notti -basictti -x86tti -targetlibinfo
2016 May 09
2
Some questions about phase ordering in OPT and LLC
On Mon, May 09, 2016 at 01:07:07PM -0700, Mehdi Amini via llvm-dev wrote:
>
> > On May 9, 2016, at 10:43 AM, Ricardo Nobre via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> >
> > Hi,
> >
> > I'm a PhD student doing phase ordering as part of my PhD topic and I would like to ask some questions about LLVM.
> >
> > Executing the following
2012 Jun 12
2
[LLVMdev] How to use LLVM optimizations with clang
Hello
I need some help here please.
If we compile source files directly in to native code:
$ clang -O3 -lm *.c
then the runtime is like following
real 0m2.807s
user 0m2.784s
sys 0m0.012s
and If we emit LLVM bytcode and apply optimizations
$ clang -O3 -c -emit-llvm *.c
$ llvm-link *.o -o comb.ll
$ time lli ./comb.ll
then the runtime is
real 0m2.671s
user 0m2.640s
sys 0m0.020s
But, if I
2012 Jun 12
2
[LLVMdev] How to use LLVM optimizations with clang
Hi
Yes, they both are exactly the same.
Regards
Shahzad
On Tue, Jun 12, 2012 at 9:38 AM, Duncan Sands <baldrick at free.fr> wrote:
> Hi, is the comb.ll used here:
>
>
>> $ time lli ./comb.ll
>>
>> then the runtime is
>>
>> real 0m2.671s
>> user 0m2.640s
>> sys 0m0.020s
>>
>> But, if I convert this same file comb,ll
2012 Jun 08
0
[LLVMdev] How to use LLVM optimizations with clang
Hello Duncan
Sorry for the mistake. Actually that error occurred when I was
compiling all the files at once, NOT in for loop.
The for loop is working perfectly as it is dealing with individual
files. I have now one new issue. Let me specify it briefly.
If I compile the program using the following command line i.e.
$ clang -O3 -lm *.c
then
$ time ./a.out
real 0m2.606s
user 0m2.584s
sys
2012 Jun 08
0
[LLVMdev] How to use LLVM optimizations with clang
Thanks Duncan
It was really helpful.
Regards
Abdul
On Fri, Jun 8, 2012 at 7:23 PM, Duncan Sands <baldrick at free.fr> wrote:
> Hi,
>
>
>> If I compile the program using the following command line i.e.
>>
>> $ clang -O3 -lm *.c
>
>
> this may be doing link time optimization.
>
>
>>
>> then
>>
>> $ time ./a.out
>>
2015 May 02
5
[LLVMdev] Modifying LoopUnrollingPass
Hi Zhoulai,
I am trying to modify "LoopUnrollPass" in llvm which produces multiple
copies of loop equal to the loop unroll factor.Currently, using multicore
architecture, say 3 for example and the execution goes like:
for 3 cores if there are 9 iterations of loop
core instruction
1 0,3,6
2 1,4,7
3 2,5,8
But I want to to
2012 Jun 12
0
[LLVMdev] How to use LLVM optimizations with clang
Hi, is the comb.ll used here:
> $ time lli ./comb.ll
>
> then the runtime is
>
> real 0m2.671s
> user 0m2.640s
> sys 0m0.020s
>
> But, if I convert this same file comb,ll in to native binary
the same as the comb.ll used here:
> $ clang comb.ll
?
Ciao, Duncan.
>
> and execute it, then the runtime increases alot
>
> $ time ./a.out
>
> real