Displaying 20 results from an estimated 1000 matches similar to: "Handling Time in R"
2011 Oct 10
1
Merge Data by time stamps
Dear all,
I have some device measurements and the time stamps I get from it have the below format:
MyStruct$TimeStamps[1,]
> [1] 2011.000 10.000 6.000 16.000 23.000 30.539
I can convert them easily with ISOdate() to a number and do the calculations I need.
One of my problems is that I want to gather my measurements to piles of duration (let's say) 5 minutes.
Afterwards I will
2012 Nov 01
2
[LLVMdev] llvm linking issue
I have three modules:
-----------------------------------------------------------------
s1.ll:
%0 = type <{ i32, i32 }>
define void @s1(%0* byval %myStruct) nounwind {
return:
ret void
}
-----------------------------------------------------------------
s2.ll:
%0 = type <{ i32, i32 }>
define void @s2(%0* byval %myStruct) nounwind {
return:
ret void
}
2012 Nov 01
0
[LLVMdev] llvm linking issue
Hi Xiaoyi, this looks like a bug to me - please file a bug report.
Ciao, Duncan.
On 01/11/12 04:35, Guo, Xiaoyi wrote:
> I have three modules:
> -----------------------------------------------------------------
> s1.ll:
>
> %0 = type <{ i32, i32 }>
>
> define void @s1(%0* byval %myStruct) nounwind {
> return:
> ret void
> }
>
2012 Oct 25
2
[LLVMdev] A question about pointer aliasing rules in LLVM
Hi,
I have the following IR code
</snippet>
%prev = getelementptr inbounds %struct.myStruct* %node, i32 0, i32 1
%1 = load %struct.myStruct** %prev, align 4, !tbaa !0
%next1 = getelementptr inbounds %struct.myStruct* %1, i32 0, i32 0
store %struct.myStruct* %0, %struct.myStruct** %next1, align 4, !tbaa !0
%2 = load %struct.myStruct** %prev, align 4, !tbaa !
</snippet>
myStruct is
2020 Jan 21
4
aarch64 does not emit DW_AT_Location
Hi Devs,
debug info emitted by llvm does not contain DW_AT_Location for Formal
parameter
if it is an aggregate like below case
1) aggregate contain more than 4 homogeneous and size more than 128 bits
i.e.
typedef struct{
int a,b,c,d,e;
}mystruct;
void foo(mystruct ms){
}
2) aggregate contain hetrogeneous type and size more than 128 bits.
i.e.
typedef struct{
int a,b;
float c,d,e;
}mystruct;
void
2002 Sep 29
1
[LLVMdev] the getelementptr noop problem
> so i confess i'm still not clear on what the first index into
> getelementptr is all about.
I'm sure you're not the only one. :) This is one of the wierdest aspects
of LLVM to the unaccustomed.
> it makes perfect sense for an example like
> getelementptr %mystruct * %reg100
> to just return a %mystruct * equivalent to %reg100.
>
> it does *not* make sense to
2019 Mar 08
1
[RFC PATCH V2 5/5] vhost: access vq metadata through kernel virtual address
On Fri, Mar 08, 2019 at 04:50:36PM +0800, Jason Wang wrote:
>
> On 2019/3/8 ??3:16, Andrea Arcangeli wrote:
> > On Thu, Mar 07, 2019 at 12:56:45PM -0500, Michael S. Tsirkin wrote:
> > > On Thu, Mar 07, 2019 at 10:47:22AM -0500, Michael S. Tsirkin wrote:
> > > > On Wed, Mar 06, 2019 at 02:18:12AM -0500, Jason Wang wrote:
> > > > > +static const
2019 Mar 08
1
[RFC PATCH V2 5/5] vhost: access vq metadata through kernel virtual address
On Fri, Mar 08, 2019 at 04:50:36PM +0800, Jason Wang wrote:
>
> On 2019/3/8 ??3:16, Andrea Arcangeli wrote:
> > On Thu, Mar 07, 2019 at 12:56:45PM -0500, Michael S. Tsirkin wrote:
> > > On Thu, Mar 07, 2019 at 10:47:22AM -0500, Michael S. Tsirkin wrote:
> > > > On Wed, Mar 06, 2019 at 02:18:12AM -0500, Jason Wang wrote:
> > > > > +static const
2011 Jan 12
2
[LLVMdev] Wrong assembly is written for x86_64 target in JIT without optimization?
When I try running one llvm function in JIT without optimization I get
SEGV. Looking at assembly (below) I see that the local value
0xffffffffffffffe0(%rbp) is used without being ever initialized (see my
comment in asm).
Same code on i386 works fine, with and w/out optimization.
My guess is that this is a bug in LLVM.
Yuri
--- llvm ---
%struct.mystruct = type { i32, i8, i8, i8, i8 }
define
2020 Jul 09
2
Understand alias-analysis results
Hey Matt,
That's awesome. Thank you very much for all the information and
clarification! Just a few follow up questions. Could you kindly shed some
lights on it? Thank you!
1. I tried to tweak the code in the following way:
- Clang [-> LLVM-IR]: https://llvm.godbolt.org/z/n9rGrs
- [LLVM-IR ->] opt: https://llvm.godbolt.org/z/Uc6h5Y
And i note that the outputs are:
Alias sets for
2012 Oct 25
0
[LLVMdev] A question about pointer aliasing rules in LLVM
On Thu, Oct 25, 2012 at 3:15 PM, Pranav Bhandarkar
<pranavb at codeaurora.org>wrote:
> Hi,
>
> I have the following IR code
>
> </snippet>
> %prev = getelementptr inbounds %struct.myStruct* %node, i32 0, i32 1
> %1 = load %struct.myStruct** %prev, align 4, !tbaa !0
> %next1 = getelementptr inbounds %struct.myStruct* %1, i32 0, i32 0
> store %struct.myStruct*
2012 Sep 19
0
[LLVMdev] newbie question on getelementptr
Hi Óscar,
Thank you for your prompt reply. Unfortunately, I still need more guidance
as using the Demo page to generate C++ code didn't result in a global
variable being used.
Basically, I'm following your advice to use a LoadInst:
Value *v = new LoadInst(result, "", theBasicBlock);
Function *myfn = cast<Function>(v);
I was not sure how I could get a BasicBlock for the
2020 Jul 09
2
Understand alias-analysis results
Hello,
I am performing alias analysis toward the following simple code:
struct MyStruct {
int * f1;
int * f2;
};
void NOALIAS(void* p, void* q){
}
int main() {
struct MyStruct s[2];
int a,b;
s[0].f1 = &a;
s[1].f1 = &b;
NOALIAS(s[a].f1, s[b].f2);
return 0;
}
When I use the following command to generate .bc code and conduct alias
analysis:
clang -c -emit-llvm t.c -O2
opt -basicaa
2012 Oct 12
2
[LLVMdev] Target backend not converting char* to struct properly.
I'm having trouble getting my backend to properly treat the situation where
a char* is converted into a struct, i.e. something like:
char* pointer_representation = ...;
MyStruct* my_struct = (MyStruct*) pointer_representation;
my_struct->an_int_field = 5;
When this occurs, LLVM seems to fold the struct and char* into one assembly
'object', which is perfectly fine. However, it also
2014 Apr 09
2
[LLVMdev] Changing the value returned by sizeof
Hello,
I'm replacing a struct with another struct of a different size. A problem
arises when the following line occurs in the source code:
MyStruct *a = malloc(sizeof(a));
The 'sizeof(a)' is turned into a constant in the LLVM IR, resulting in the
wrong amount of memory being allocated for the struct. Is there any way to
find all the constants that have arisen from sizeof?
Thanks,
2012 Oct 12
0
[LLVMdev] Target backend not converting char* to struct properly.
On Fri, Oct 12, 2012 at 10:43 AM, Stephen McGruer
<stephen.mcgruer at gmail.com> wrote:
> I'm having trouble getting my backend to properly treat the situation where
> a char* is converted into a struct, i.e. something like:
>
> char* pointer_representation = ...;
> MyStruct* my_struct = (MyStruct*) pointer_representation;
> my_struct->an_int_field = 5;
>
>
2015 May 21
2
[LLVMdev] MemoryDependenceAnalysis reports dependencies between NoAlias pointers
Hi all,
I have a custom alias analysis pass that enforces that pointers from different address spaces do not alias, and I'm using MemoryDependenceAnalysis to, well, figure out dependence analysis.
The AA pass is extremely simple, it only checks the address space of pointers, returns NoAlias if they're different, and delegates otherwise. It is the last alias analysis pass added to my
2012 Sep 19
3
[LLVMdev] newbie question on getelementptr
Hi All,
I'm new to LLVM and I'm having a coding problem.
I'm creating a GlobalVariable that contains a StructType that contains a
Function. The function returns i32 and takes two i32's.
Here is my code:
GlobalVariable* retrieved = module->getGlobalVariable("myGV");
...
Constant* result = ConstantExpr::getGetElementPtr(retrieved, indices);
How do I get my Function
2015 May 21
2
[LLVMdev] MemoryDependenceAnalysis reports dependencies between NoAlias pointers
Thanks Daniel,
I'll do a debug build of LLVM (I guess that'll teach me) and step through it as soon as I'll find a power outlet.
I'm calling getDependency on the load instruction, and it returns the store instruction. Suspiciously enough, calling invalidateCachedPointerInfo on load->getPointerOperand() does not cause my AA pass to be called again when I use getDependency (or
2013 Aug 29
23
[PATCH] Btrfs: optimize key searches in btrfs_search_slot
When the binary search returns 0 (exact match), the target key
will necessarily be at slot 0 of all nodes below the current one,
so in this case the binary search is not needed because it will
always return 0, and we waste time doing it, holding node locks
for longer than necessary, etc.
Below follow histograms with the times spent on the current approach of
doing a binary search when the