similar to: [LLVMdev] Special cased global-to-local-in-main replacement in GlobalOpt

Hi all, I had a look at the interprocedural optimizer. In my opinion the routine 'GlobalOpt::ProcessInternalGlobal' is a little bit to conservative. It removes global variables if the only routine using this variable is main. Typically this condition is valid only for very few global variables. Here is a code snippet containing the test before the transformation: file:

The code excerpt is from IPO/GlobalOpt.cpp // If this is a first class global and has only one accessing function // and this function is main (which we know is not recursive we can make // this global a local variable) we replace the global with a local alloca // in this function. // // NOTE: It doesn't make sense to promote non single-value types since we // are

Hello everyone, This is a rather ancient code with Chris's name all over it, so I naturally feel humbled :) I see a conceptual issue in lib/Transforms/IPO/GlobalOpt.cpp with several optimizations that create a copy of GlobalVariable without copying attributes from the original one. Consider this one: http://llvm.org/doxygen/GlobalOpt_8cpp_source.html static bool

Given some code: static int x = 100; int main() { x = 101; printf("%d\n", x); } results in: %0 = load i1 %1 = select %0, 101, 100 ... ... 1) What architecture(s) does this benefit? 2) What's the best way to circumvent this in the backend (currently I am just not allowing this opt function to run)? I have tried a few setOperationAction methods to no result. Rather not just

Chris, Thanks for the clarification... at least no bug report is due... and I am glad that I've asked. In my case these transformations are rather useful and forcing them to copy original global variable section is making them compatible with our (rather important) use case, so I guess I will have to fix it locally. Nevertheless if someone else would have a similar issue - I would be

Hi Mehdi, You are right – modifying the Function Attributes pass to mark “main” as norecurse would break the C standard (unless it has a similar statement regarding “main” that the C++ standard has – I cannot find it), so that’s a no-go. Looks like there was an attempt to bypass library calls in the Function Attributes pass for the purpose of detecting norecurse functions:

Hi, GlobalOpt may not consider demoting globals to locals in the "main" function when C is used. It used to consider "main" specifically prior to commit r253168 , for both C and C++. Since r253168, the check for the norecurse attribute may prevent "main" from being considered. This happens because the Function Attributes pass will not add the norecurse

Yes, the full test case is: static int x = 100; int y = whatever; int main() { x = -101; y = whatever that's not whatever above; printf("%d\n", y); printf("%d\n", x); return 0; } You are correct, in the above test case the globalopt does not make the transformation.... however, I think the original issue still stands, it really shouldn't be doing it

I think the conceptual issues have largely been sorted out, it is mostly that it is *much* harder to deduce norecurse than it might seem like superficially. On Mon, Mar 21, 2016 at 4:02 PM Mehdi Amini <mehdi.amini at apple.com> wrote: > On Mar 21, 2016, at 3:57 PM, Sanjin Sijaric via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > > Hi, > > GlobalOpt may not

Hi, On my phone right now but I'll fish out the pertinent threads when I get to the office. Keyword searches for 'norecurse' on llvm-dev will probably get most of them. Indeed, this correctness improvement caused a performance regression on some programs. There is a way to revert to the old, broken behaviour: '-mllvm -force-attribute=main:norecurse'. Given how many people run

I just got the CVS version of LLVM running tonight. On my PowerBook, one of the examples (HowToUseJIT) has an assertion error when I try and run it: Running foo: JIT.cpp:217: failed assertion `!isAlreadyCodeGenerating && "Error: Recursive compilation detected!"' However, when I compile and run the same program on x86 Linux, it runs fine (Running foo: Result: 11). I

On Feb 20, 2005, at 11:12, Evan Jones wrote: > I can "fix" it by changing JITResolver::getFunctionStub to use > F->isExternal() instead of F->hasExternalLinkage(). However, this then > breaks when calling *real* external functions (native code). I obviously should not post to mailing lists before I've eaten. With my "fix" I get an assertion when taking an

rails: hi guys, one problem makes me even crazy! I use ruby on rails and mysql, but the table''s collum names in the mysql database is mixed case, not only lower case. but I do have set the database lower_case_tablenames=1, but still, the ruby on rail can not access mysql by just lower case table collums. why?! help! Regards! Su Siyuan siyuan.su@accessmedia.com.cn 2006-04-11

Hi folks, TableGen provides sufficiently rich syntax for expressing target instruction set. Nevertheless, when I wrote the PTX backend, I observed that some redundancy in TableGen can be further eliminated through macro expansion of for-loops. The semantics of a for-loop is expanding the for-loop body, and so it is equivalent to manually unroll the loop (see example #1). I believe the for-loop

Mon Ping, Thanks for the tip, but I can't for the life of me seem to get the Value from a StoreSDNode. From looking at the SelectionDAGNodes header file, the only class that has the getValue function call is SrcValueSDNode that returns a Value type. The only class that has getType is a ConstantPoolSDNode. I don't think that ConstantPoolSDNode is what I want and when I try to cast the

Every GlobalAddress has a GlobalValue, Every GlobalValue is a PointerType, Every PointerType has an AddressSpace. So is it ok to add a method getAddressSpace in GlobalAddressSDNode class itself? Currently we have to do GSDN->getGlobal()->getType()->getAddressSpace(). - Sanjiv

Hi, Sent via the Samsung Galaxy Note® 3, an AT&T 4G LTE smartphone -------- Original message -------- From: Gurunath Kadam via llvm-dev <llvm-dev at lists.llvm.org> Date: 11/27/2016 7:49 PM (GMT-06:00) To: llvm-dev at lists.llvm.org Subject: [llvm-dev] LLVM Pass for Instructions in Function (error Hi, Please find the embedded code. Also you may follow

Hi, I'd like to fix PR19590, which is about llvm.global_ctors containing functions that end up being empty after optimization (which causes the linker to add useless init_array entries to the output binary). globalopt removes empty functions from llvm.global_ctors, but by the time the function becomes empty globalopt has already run and it doesn't run again. I'm wondering what the

The address qualifier is stored in the type of %result. From that operand, you can get the Value and then call getType. The type for result should be a PointerType which you cast to a PointerType and get the getAddressSpace e.g. cast<PointerType>(Ty)->getAddressSpace() -- Mon Ping On Sep 17, 2008, at 1:06 PM, Villmow, Micah wrote: > How do I access the address qualifier

Hi, I've been able to link ioquake, but not without a small modification to lib/Linker/LinkModules.cpp:427 where I had to add: } else if (Dest->hasExternalLinkage() && Src->hasExternalLinkage()){ LinkFromSrc = true;//overwrite old value LT = Src->getLinkage();//use src linkage The reason is that two files both had a global function pointer variable (due