similar to: [PATCH] strlen -> strnlen optimization

Joerg Sonnenberger wrote: > On Sat, Feb 06, 2016 at 11:05:14PM -0500, Michael McConville via llvm-dev wrote: > > This addition converts strlen() calls to strnlen() when the result is > > compared to a constant. For example, the following: > > > > strlen(s) < 5 > > > > Becomes: > > > > strnlen(s, 5) < 5 > > > > That way, we

Hello ! I want some piece of advice regarding a LLVM pass. My particular problem is: There is a method bool patternDC::runOnFunction(Function &F) { ... if ( CC->operEquiv(icmpInstrArray[i], icmpInstrArray[j]) ) {...} ... } having the array elements of type Instruction* : http://llvm.org/doxygen/classllvm_1_1Instruction.html The called method is bool

Hi all, I have a question regarding a transformation that is carried out in InstCombine, which has been introduced by r48715. It unfolds expressions of the form `zext(or(icmp, (icmp)))` to `or(zext(icmp), zext(icmp)))` to expose pairs of `zext(icmp)`. In a subsequent iteration these `zext(icmp)` pairs could then (possibly) be optimized by another optimization (which has already been there before

It seems that fast-isel for intel does not handle strlen. It's a general problem in fast-isel . ~/llvmw/build/Deb~/llvmw/build/Debug+Asserts/bin/clang -O0 -mllvm -fast-isel-verbose -mllvm -fast-isel strlen1.c strlen1.c:12:3: warning: implicitly declaring library function 'printf' with type 'int (const char *, ...)' printf("%i\n", len); ^

Hi all: I am trying to compare the return value of a call instruction with 0. The called function's return type is uint32. The return value is 1 or 0. But the icmp instruction cannot be created. CallInst *ret = CallInst::Create(ptr_func, params.begin(), params.end(), "", bb); Value *cmp = new ICmpInst(*bb, ICmpInst::ICMP_EQ, ret, ,ConstantInt::get(getIntegerType(32), 0)

On Wed, Dec 12, 2012 at 01:59:55PM -0800, Dan Gohman wrote: > The bug here isn't in clang's use of noalias or in BasicAliasAnalysis' > implementation of noalias; it's in the code that's optimizing the > icmp. Let's come back to this. The attached patch decouples InstSimplify from the alias analysis and provides the conservative logic for when pointers are not

[Ooops, sent to the old list address by mistake] On 30 Jul 2015, at 21:04, tom at stellard.net wrote: > > For flags like -fno-rtti (are there others?) that are required in some cases > (I think -fno-rtti is required only if you sub-class LLVM objects), I would propose > adding a separate flag like --uses-rtti. This would give users more fine-grained > control over which flags

I'm trying to come up with a simple example of using ICmpInst in a Pass. On each of the branches(true, false) I'd like to call a separate function and then resume(to the code that was already there). In this example i is a inst_iterator to Instruction the Pass is currently on. Now it segfaults opt before I can even get a dump() on it. Does anyone see what I am doing wrong? BasicBlock

Hi Sanjay, thank you a lot for your answer. I understand that in your examples it is desirable that `foo` and `goo` are canonicalized to the same IR, i.e., something like `@goo`. However, I still have a few open questions, but please correct me in case I'm thinking in the wrong direction. > Am 21.07.2016 um 18:51 schrieb Sanjay Patel <spatel at rotateright.com>: > > I've

In a pass I would like to insert a ICmpInst/BranchInst pair to check if 2 GlobalVariables are equal or not. If they are not I would like to call a function. I've tried splitting the current block and then inserting before the existing instructions, but for some reason this seems to ruin the iterator(i). What is the correct way todo something like this? void checkShadowPtr(Module &M,

Be careful about oversimplifying signed integer comparisons -- integer arithmetic can easily overflow, so you cannot transform A > B to A - B > 0. The compare instructions in most processors do not simply subtract and test the most significant bit; they compute what the sign of the difference would be in extended precision. On Apr 17, 2010, at 1:00 PM, llvmdev-request at cs.uiuc.edu wrote:

Should have changed the subject line... --- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation > -----Original Message----- > From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] > On Behalf Of Sergei Larin > Sent: Wednesday, July 03, 2013 12:29 PM > To: 'Tobias Grosser' > Cc: 'llvmdev'

Hi Sergei, On Thu, Jul 4, 2013 at 1:36 AM, Sergei Larin <slarin at codeaurora.org> wrote: > Should have changed the subject line... > > --- > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted > by > The Linux Foundation > > > > -----Original Message----- > > From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at

On Fri, Aug 7, 2015 at 10:22 AM, Hans Wennborg via llvm-dev < llvm-dev at lists.llvm.org> wrote: > On Thu, Aug 6, 2015 at 12:04 PM, David Chisnall via llvm-dev > <llvm-dev at lists.llvm.org> wrote: > > [Ooops, sent to the old list address by mistake] > > > > On 30 Jul 2015, at 21:04, tom at stellard.net wrote: > >> > >> For flags like

Hi, i am playing the ScalarEvolution these days. i found the the ScalarEvolution will simply return a SCEVUnknow for a ICmpInst, so i think maybe great to add a new kind of SCEV to the ScalarEvolution framework. for example, if i run ScalarEvolution on the bc file generate from the following C source file: int f(int a, int b, int c, int d) { return (2 * a + 5 * c + 2) > (4 * d - 3*b

On Tue, Sep 27, 2011 at 7:28 PM, ret val <retval386 at gmail.com> wrote: > I'm trying to come up with a simple example of using ICmpInst in a > Pass. On each of the branches(true, false) I'd like to call a separate > function and then resume(to the code that was already there). > > In this example i is a inst_iterator to Instruction the Pass is > currently on. Now

This might be hard cases making bad law, but the loop: void f (unsigned short *x, int *l) { int c = *l; int i; for (i = 0; i < c; i++) if (x[i]) x[i]++; } is converted to decrement-and-branch form by LoopStrengthReduce while: void f (unsigned short *x, int *l) { int i; for (i = 0; i < *l; i++) if (x[i]) x[i]++; } isn't.

I’ve almost finished a patch to add back in either out of line destructors or anchor methods. We seem to use one or the one, relatively inconsistently. What i’ve gone for is that if a class already had an inline destructor then i left it alone and added an anchor method. Otherwise I added an out of line destructor. Now if I compile Instructions.cpp with -Wweak-vtable, the only warnings given

Hi Sanjoy, Your inputs really helped. Using “isImpliedCond”, able to relate and find the min for cases like: SCEV1: (-1 + (sext i32 %n.addr.058 to i64))<nsw> SCEV2: 0 Extra-Condition: (n.addr.058 > 7) Result: ‘0’ (SCEV2) I have another case where trying to find min between two SCEVs under an extra condition. “isImpliedCond” is not helping for below case, may be I’m missing something:

On Tue, Oct 11, 2011 at 7:22 PM, ret val <retval386 at gmail.com> wrote: > In a pass I would like to insert a ICmpInst/BranchInst pair to check > if 2 GlobalVariables are equal or not. If they are not I would like to > call a function. I've tried splitting the current block and then > inserting before the existing instructions, but for some reason this > seems to ruin the