similar to: [LLVMdev] removing dead function calls

On Jul 25, 2010, at 6:48 AM, Jochen Wilhelmy wrote: > Hi! > > I have code with dead function calls which are not removed. Is it possible > to mark functions that have no side effects (e.g. sin() or floor() ) so > that they > are removed by dead code elimination? Yep, just add the readonly/readnone attributes to the call site or function and they should be deleted if dead.

Hi! if I have a function with readnone attribute. is it then allowed to access an "internal constant" which is defined outside the function in llvm ir assembly? -Jochen

Hi! > sin/cos etc should already be handled by lib/Analysis/ConstantFolding.cpp. > Thanks for the hint and it works! Now I have a new Problem: I have this function: float foo(float a, float b) { float x = a * b * 0.0f; return cos(0.5) * sin(0.5) * x; }; after compiling it with clang (cpp mode) and renaming _ZSt3sinf to sin and _ZSt3cosf to cos I get the following: define

On 3 March 2010 11:56, Jochen Wilhelmy <j.wilhelmy at arcor.de> wrote: > > the sin and cos calls are folded, but not the mul by zero. > Is x*0 => 0 true if isnan(x)? And cos(x)*sin(x) makes me desperately want to fold it to sin(2*x)/2, but I suppose that's not allowed either.

> Yep, just add the readonly/readnone attributes to the call site or function and they should be deleted if dead. See LangRef.html for more info. > > Is it even possible to define this attribute in clang? e.g. __attribute__(readnone) float sin(float x); -Jochen

Hi! in the llvm code there are several places with hardcoded function names for e.g. sin, sinf, sqrt, sqrtf etc., namely ConstantFolding.cpp InlineCost.cpp SelectionDAGBuilder.cpp IntrinsicLowering.cpp TargetLowering.cpp my question is: wouldn't it be beneficial to use intrinsics for this? for example a c/c++ frontend (clang) could translate the function calls to intrinsics and then in a

On 25.11.2010 23:56, Michael Spencer wrote: > On Nov 25, 2010, at 5:01 PM, Jochen Wilhelmy <j.wilhelmy at arcor.de > <mailto:j.wilhelmy at arcor.de>> wrote: > >> Hi! >> >> Of course nobody wants to implement unicode support for windows >> because windows should support an utf8-locale and windows is obsolete >> anyway ;-) >> >> But

On Nov 25, 2010, at 5:01 PM, Jochen Wilhelmy <j.wilhelmy at arcor.de> wrote: > Hi! > > Of course nobody wants to implement unicode support for windows > because windows should support an utf8-locale and windows is obsolete > anyway ;-) > > But there is a simple solution: use boost::filesystem::path everywhere you > use file names and paths, for example in

Hi! Of course nobody wants to implement unicode support for windows because windows should support an utf8-locale and windows is obsolete anyway ;-) But there is a simple solution: use boost::filesystem::path everywhere you use file names and paths, for example in clang::FileManager::getFile. With version 3 opening a file is easy: std::fstream file(path.c_str()). Internally

Now I have -DLLVM_INCLUDE_EXAMPLES:BOOL=OFF but Kaleidoscope is still there and selected for build (-G "Visual Studio 9 2008") -Jochen

Hi! Is it possible that you add an example how to write a .o with llvm? Just like examples/ModuleMaker but instead of printing to stdout writing a .o file as starting point for the new MC functionality. -Jochen

Hi! I'd like to replace all calls to standard math functions (e.g. sin(0.5)) by their result. What strategy do you recommend? Should I write a pass that does only this or should I copy and modify the SCCP pass? A problem with an extra pass could be that that I need to alternate my pass and SCCP several times since the results of the math functions could be folded again. -Jochen

Hi! when compiling projects using llvm 2.9 and ms vc 10 I get these warnings: 1>e:\Jochen\Lib\lib\include\llvm/Use.h(218): warning C4624: 'llvm::AugmentedUse' : destructor could not be generated because a base class destructor is inaccessible 1>C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\stdint.h(72): warning C4005: 'INT8_MIN' : macro redefinition

On Fri, 26 Nov 2010 09:28:17 -0500 Michael Spencer <bigcheesegs at gmail.com> wrote: > On Fri, Nov 26, 2010 at 4:00 AM, Jochen Wilhelmy > <j.wilhelmy at arcor.de> wrote: > > No, this post was prompted since I switched to boost::filesystem > > version 3 in my own code and llvm/clang 2.8 > > was the only lib with no unicode support on windows. > > Will your

On Fri, Nov 26, 2010 at 4:00 AM, Jochen Wilhelmy <j.wilhelmy at arcor.de> wrote: > No, this post was prompted since I switched to boost::filesystem version 3 > in my own code and llvm/clang 2.8 > was the only lib with no unicode support on windows. > Will your code be api compatible to boost::filesystem? No. boost::filesystem makes extensive use of exceptions, which LLVM is

Hello Jochen- Your expectation is incorrect, I'm afraid. Typically this would be expanded to something like this: … %cmp = … br i1 %cmp, label %ternary.true, label %ternary.false ternary.true: %truevalue = … br label %ternary.end ternary.false: %falsevalue = … br label %ternary.end ternary.end: %value = phi %type [%truevalue, %ternary.true], [%falsevalue,

Hi! In DataTypes.h (generated from DataTypes.cmake) there is an extra code path for Visual C. This can produce macro redefinitions for INT8_MAX, INT8_MIN etc. since other headers may also define them. Therefore please protect the macros like INT8_C etc. Also it would be nice if the auto-generated HAVE_STDINT_H and HAVE_INTTYPES_H would be used also for Visual C since it is possible to add them

Am 29.12.2011 19:52, schrieb Reid Kleckner: > I think Chris is saying that the and is necessary because with your i1 > trunc you're ignoring all of the high bits. The and implements that. > If you don't want this behavior, don't generate the trunc in the > first place and just compare the full width to zero. But if a backend sees trunc from i8 to i1 it should know

I think Chris is saying that the and is necessary because with your i1 trunc you're ignoring all of the high bits. The and implements that. If you don't want this behavior, don't generate the trunc in the first place and just compare the full width to zero. Reid On Wed, Dec 28, 2011 at 6:45 AM, Jochen Wilhelmy <j.wilhelmy at arcor.de>wrote: > > >> Hi! >

>> Hi! >> >> before InstCombine (llvm::createInstructionCombiningPass()) I have >> a trunc from i8 to i1 and then a select: >> >> %45 = load i8* @myGlobal, align 1 >> %tobool = trunc i8 %45 to i1 >> %cond = select i1 %tobool, float 1.000000e+00, float -1.000000e+00 >> >> after instCombine I have: >> >> %29 = load i8*