similar to: [LLVMdev] memcpy function in LLVM

> On Jan 18, 2018, at 7:45 AM, Daniel Neilson via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > > Hi all, > This change has been reviewed, and appears to be ready to land (review available here if anyone still wants to chime in: https://reviews.llvm.org/D41675 <https://reviews.llvm.org/D41675> ). The process that we’re going to use for landing this will take a few

Hi all, This change has been reviewed, and appears to be ready to land (review available here if anyone still wants to chime in: https://reviews.llvm.org/D41675 ). The process that we’re going to use for landing this will take a few steps. To wit: Step 1) Remove align argument, and add align attribute to pointer args. Require that src & dest have the same alignment via verifier rule. Also

Hi Daniel, a quick question (and kind-of a follow-up to <https://lists.llvm.org/pipermail/llvm-dev/2017-July/115665.html>): Do the pointers have to be aligned even if the size is 0? It would be nice to have this stated explicitly in the LangRef. Kind regards, Ralf On 26.03.2018 22:43, Daniel Neilson via llvm-dev wrote: > Hi all, >  A quick note just to let people know that as of

Hi all, A quick note just to let people know that as of this past Friday my go at this work has been fully landed. It ended up being a back-burner item, so it took longer than I would have liked to get completed. None the less, the changes made were: 1) The IRBuilders in LLVM, Clang, and Polly were all updated to create only the new form of the memory intrinsics. 2) All LLVM passes to understand

Good day all, I’ve spent a few days resurrecting the circa-2015 work on removing the explicit alignment argument (4th arg) from the @llvm.memcpy/memmove/memset intrinsics in favour of using the alignment attribute on the pointer args of calls to the intrinsic. This work was first proposed back in August 2015 by Lang Hames: http://lists.llvm.org/pipermail/llvm-dev/2015-August/089384.html (item

Hi All, I have a question on ConstantExpressions and llvm intrinsic memcpy/memset/memmove. I am using llvm-2.8 release. In one of the C programs that I am compiling using clang frontend, the call to memcpy instrinsic looks like the following call void @llvm.memcpy.p0i8.p0i8.i64(i8* %tmp2, i8* bitcast (%struct.ta* @tret to i8*), i64 4, i32 4, i1 false), !dbg !19 The second argument to memcpy is

On Jan 18, 2018, at 10:48 PM, Chris Lattner <clattner at nondot.org<mailto:clattner at nondot.org>> wrote: On Jan 18, 2018, at 7:45 AM, Daniel Neilson via llvm-dev <llvm-dev at lists.llvm.org<mailto:llvm-dev at lists.llvm.org>> wrote: Hi all, This change has been reviewed, and appears to be ready to land (review available here if anyone still wants to chime in:

On 4/14/11 6:34 PM, Kodakara, Sreekumar V wrote: > > Hi All, > > I have a question on ConstantExpressions and llvm intrinsic > memcpy/memset/memmove. I am using llvm-2.8 release. In one of the C > programs that I am compiling using clang frontend, the call to memcpy > instrinsic looks like the following > > call void @llvm.memcpy.p0i8.p0i8.i64(i8* %tmp2, i8* bitcast

+ llvm-dev On 25 Aug 2020, at 13:53, Florian Hahn wrote: > Hi, > > It appears that Clang generates calls to `llvm.memcpy` with > potentially overlapping arguments in some cases. > > For the snippet below > > struct S > { > char s[25]; > }; > > struct S *p; > > void test2() { > ... > foo (&b, 1); > b = a; > b = *p; > ...

Hi, LLVM's memory intrinsics are quite useful for performing various optimizations with frequently used memory operations. Unfortunately this intrinsics are not applicable for languages with guaranteed atomicity for their memory accesses (like Java for example). In order to overcome this limitation I'm thinking about adding set of intrinsics which will execute as a series of unordered

Guess I have found some clues. Some necessary libraries have to be loaded while trying to generate native code or do interpretation. Then another question emerges: Is there a way to determine the necessary libraries in need? And where to locate these necessary libraries? Xiaolong > Hi All, > > I have a program that uses C++ STL a lot. To have the source code for > STL functions, I

Hi Xialong, > I have a program that uses C++ STL a lot. To have the source code for > STL functions, I undefined "_GLIBCXX_EXTERN_TEMPLATE" in > c++config.h. In spite of this, after compilation (via clang) and > linking (via llvm-ld), the resulting bitcode contains a few declared > functions (with no definitions). > > My question is: In the scenario where some

> could you allocate the memory on the stack instead (alloca instruction)? This is mainly for string or binary blob handling, using the stack isn't a great idea for size reasons. While I'm experimenting with simple code examples now, and I picked a simple one for this email. I'm certain things will get much more complicated once I implement more features of the language. On Tue,

Hi All, I have a program that uses C++ STL a lot. To have the source code for STL functions, I undefined "_GLIBCXX_EXTERN_TEMPLATE" in c++config.h. In spite of this, after compilation (via clang) and linking (via llvm-ld), the resulting bitcode contains a few declared functions (with no definitions). My question is: In the scenario where some function definitions are missing in a llvm

On 3/22/2018 3:15 PM, Andrew Kelley via llvm-dev wrote: > The new @llvm.memcpy API does not have an alignment parameter. Instead > the docs say to use the align <n> attribute. How is this supposed to > work with different alignments? > > For example, I have one memcpy with align 4, align 4, and another with > align 1, align 1. > > ; Function Attrs: argmemonly

The new @llvm.memcpy API does not have an alignment parameter. Instead the docs say to use the align <n> attribute. How is this supposed to work with different alignments? For example, I have one memcpy with align 4, align 4, and another with align 1, align 1. ; Function Attrs: argmemonly nounwind declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly align 4, i8* nocapture

Hi Xiaolong, > As Duncan described, "lli -load=libstdc++.dylib ..." works. I, > however, encounted an "Illegal instruction" message, while I was > trying to interpret a large program. are you using the interpreter or the JIT? So, does lli have a debug switch > for dumping out the details for errors? > > Using llc is not that simple, and I have not gotten

The front end I'm building for an existing interpreted language is unfortunately producing output similar to this far too often; define void @foo(i8* nocapture %dest, i8* nocapture %src, i32 %len) nounwind { %1 = tail call noalias i8* @malloc(i32 %len) nounwind tail call void @llvm.memcpy.p0i8.p0i8.i32(i8* %1, i8* %src, i32 %len, i32 1, i1 false) tail call void

Thanks Duncan and Ashok, As Duncan described, "lli -load=libstdc++.dylib ..." works. I, however, encounted an "Illegal instruction" message, while I was trying to interpret a large program. So, does lli have a debug switch for dumping out the details for errors? Using llc is not that simple, and I have not gotten through the compilation process. For instance, "llc -o

SROA optimization pass did some optimizations and transforms for memcpy function,such as ld/st operations.When someone has written down code like size>sizeof(dest) in memcpy(*dest,*src,size), there was much likely a wrong code generation.for example,considered as such testcase: int main() { char ch; short sh = 0x1234; memcpy(&ch,&sh,2); printf("ch=0x%02x\n",ch); } At