similar to: [LLVMdev] Alias Analysis: zero terminated strings

Carl-Philip Hänsch wrote: > Hello, > > I'm developing a programming language that is optimized for strings. A > first hello world program shows me that llvm needs a lot more work on > zero terminated strings. > In the following example, I have an auto generated hello world example > optimized with -O3. The problem is, that the constant string is copied > into a malloced

I found that LLVM optimized the IR by replacing printf with puts. I wondered which pass did this optimization? And is it common that puts is faster (and some other metric) than printf? -- Thanks Thomson -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20120617/08aa6c45/attachment.html>

Hi, I would like to propose that when available, if a C builtin function has an equivalent llvm intrinsic, that the intrinsic be the preferred form. The equivalent clang __builtin should emit the intrinsic, and SimplifyLibCalls should replace calls with the intrinsic. For context, this came up on an old review thread: http://reviews.llvm.org/D5896 There are a few motivations for this: 1.

Hi All, I finally got around to cleaning up my proposal to merge `SimplifyLibCalls` into `InstCombiner`. There is still an open question or two and I am sure there are parts that could be better specified, but this is good enough to discuss. Feedback is most welcome. Abstract ======== This proposal is an attack plan for PR11895 [1]. Currently within LLVM we have two passes that are used to

Hi Thomson, the new call to puts() is inserted right away, whereas the old call to printf() is removed a bit later in SimplifyLibCalls::runOnFunction(). If you browse the code a bit and backtrack the call stack to see what happens with the return value of PrintFOpt::OptimizeFixedFormatString(), you will stumble upon this segment in SimplifyLibCalls.cpp:1703ff.: // Try to optimize this call.

On Feb 13, 2011, at 12:24 AM, Chris Lattner wrote: > On Feb 2, 2011, at 10:11 AM, Richard Osborne wrote: >> The newlib C library provides iprintf(), a restricted version of printf >> without support for floating-point formatting. I'd like to add an >> optimization which turns calls to printf() into calls to iprintf() if >> the format string has no floating point

The newlib C library provides iprintf(), a restricted version of printf without support for floating-point formatting. I'd like to add an optimization which turns calls to printf() into calls to iprintf() if the format string has no floating point specifiers. At the moment I've got this working locally by adding code to the simplify-libcalls pass. However this will break on targets

To this day, we still do too little when it comes to optimizing well known library calls. Given that various libraries, especially the C/C++ standard library, are relatively clear defined, and LLVM has all the infrastructure already in place, e.g., SimplifyLibCalls.cpp, it seems odd that we still miss so many optimization opportunities. To show how easy it is, and how much impact it can have, I

On Feb 2, 2011, at 10:11 AM, Richard Osborne wrote: > The newlib C library provides iprintf(), a restricted version of printf > without support for floating-point formatting. I'd like to add an > optimization which turns calls to printf() into calls to iprintf() if > the format string has no floating point specifiers. Cool, ok. I can see how this would be very useful for a

On Feb 18, 2013, at 4:45 PM, Chris Lattner <clattner at apple.com> wrote: > > On Feb 18, 2013, at 1:54 PM, Bill Wendling <wendling at apple.com> wrote: > >> Hi LLVMites! >> >> This patch adds the 'nobuiltin' attribute to to LLVM. This is needed during LTO, which right now ignores this attribute and command line flag. I want to make this an

Hi, It looks like SimplifyLibCalls has a tendency to emit calls to libm functions without checking with TLI whether these calls are available. For example, PowOpt has this code: struct PowOpt : public UnsafeFPLibCallOptimization { PowOpt(bool UnsafeFPShrink) : UnsafeFPLibCallOptimization(UnsafeFPShrink) {} virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B)

On Tue, Aug 13, 2013 at 5:58 AM, Kuperstein, Michael M < michael.m.kuperstein at intel.com> wrote: > Hi,**** > > ** ** > > It looks like SimplifyLibCalls has a tendency to emit calls to libm > functions without checking with TLI whether these calls are available.**** > > For example, PowOpt has this code:**** > > ** ** > > struct PowOpt : public

attached is the diff of vcprojs that need to be changed to fix the VS build as of revision: 51224. I don't know if this catches all the missing bits, but this does build all the way through. -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: msvs.patch URL:

Hi, LLVM optimizer seems to leave "call exit" instruction in "main" function but it could be replaced by a return instruction. Any reason why leave it as is or this simple optimization could be implemented e.g. in SimplifyLibCalls? Thanks -------------- next part -------------- An HTML attachment was scrubbed... URL:

On Apr 27, 2012, at 2:02 PM, Eli Friedman wrote: > On Fri, Apr 27, 2012 at 12:09 PM, Akira Hatanaka <ahatanak at gmail.com> wrote: >> while gcc does it in two move instructions: >> >> $ gcc foo1.c -S -o -O3 >> foo1: >> .LFB0: >> .cfi_startproc >> movq %xmm0, -8(%rsp) >> movss -8(%rsp), %xmm0 >> >>

Hi Victor, this code from the verifier broke the Ada front-end build: const Module* M = CI.getParent()->getParent()->getParent(); Constant *MallocFunc = M->getFunction("malloc"); if (CI.getOperand(0) == MallocFunc) { const PointerType *PTy = PointerType::getUnqual(Type::getInt8Ty(CI.getParent()->getContext())); Assert1(CI.getType() == PTy, "Malloc

On Feb 24, 2011, at 12:41 AM, John Criswell wrote: >>>> At the moment I've got this working locally by adding code to the >>>> simplify-libcalls pass. However this will break on targets where >>>> iprintf() isn't available. Is there a sensible place to add information >>>> about which library functions are available for a particular target?

On Feb 18, 2013, at 4:49 PM, Bill Wendling <wendling at apple.com> wrote: >> Hi Bill, >> >> I think the concept of this patch makes sense, but the implementation does not. >> >> I have: >> >> void foo() { >> printf("hello\n"); >> } >> >> and I build with -fno-builtin-puts. If I understand correctly, *foo* will

Hi Dmitri, For what version of VS did you update the project files? Ted On May 17, 2008, at 3:00 PM, Dmitri Makarov wrote: > attached is the diff of vcprojs that need to be changed to fix the VS > build as of revision: 51224. > > I don't know if this catches all the missing bits, but this does build > all the way through. > > > Index: win32/Analysis/Analysis.vcproj

I have hit a fairly isolated practical issue deploying the new PM, but it does point to a latent theoretical issues as well. I see various ways to address it, but want feedback from others before moving forward. The issue is that we can introduce out-of-thin-air calls to known library functions (`SimplifyLibCalls`, etc). These can be introduced in function passes (`InstCombine` in particular) and