search for: isnotduplicable

...ment. There are a couple of different approaches that could be taken to implement this: 1. Parse the content of the assembly string argument to the asm statement in the compiler front-end (during EmitAsmStmt(), for example) to determine if it contains a label definition, and if it does set the isNotDuplicable flag on the INLINEASM record that is created to represent the asm statement in the IR. To date, there is no precedence for processing the content of the assembly string argument until the asm statement is invoked before the integrated assembler starts processing the generated machine code. 2. A...

...E: [llvm-dev] [RFC] Potential extension to asm statement functionality The proposed "lbl" constraint below: __asm __volatile__ ("\t.global\t%0\n%0:\n" : "lbl" (my_hook_fcn)); is not quite a "No Touchie!" constraint, but it does allow the user to set the isNotDuplicable flag on the INLINEASM that comes out of the asm statement in order to circumvent optimizations like Tail Duplication. But setting the isNotDuplicable flag is not really enough. If the function that contains the "lbl" constrained asm statement is inlined into a function in the same compil...

...t. There are a couple of different approaches that could be taken to implement this: 1. Parse the content of the assembly string argument to the asm statement in the compiler front-end (during EmitAsmStmt(), for example) to determine if it contains a label definition, and if it does set the isNotDuplicable flag on the INLINEASM record that is created to represent the asm statement in the IR. To date, there is no precedence for processing the content of the assembly string argument until the asm statement is invoked before the integrated assembler starts processing the generated machine code. 2....

On Jun 24, 2010, at 7:00 AMPDT, Xinfinity wrote: > > I need to mark the beginning of some regions of code, that I want to > patch at > runtime. > In this case, I want to mark the beginning of BB4 and then to patch > the > jumps, because I want to temporarily change the flow at runtime and > then to > restore the previous version. > > In order to patch, I

I need to mark the beginning of some regions of code, that I want to patch at runtime. In this case, I want to mark the beginning of BB4 and then to patch the jumps, because I want to temporarily change the flow at runtime and then to restore the previous version. In order to patch, I need to know the exact structure of the generated code. So, I might have a BasicBlock like: BB4: call void asm

This came up a long time ago, but I'm not sure what the resolution was: http://lists.cs.uiuc.edu/pipermail/llvmdev/2009-October/026312.html There's also TID::isNotDuplicable: http://llvm.org/docs/doxygen/html/classllvm_1_1TargetInstrDesc.html#ab05b074805f22503828b5b625d437f3a I don't know enough about LLVM's backend to say if you can get that on an intrinsic. Reid On Thu, Apr 14, 2011 at 5:24 PM, Dmitry Denisenko <DDENISEN at altera.com> wrote: > He...

...ite operation on the full virtual register which cannot be // moved safely. if (TargetRegisterInfo::isVirtualRegister(DefReg) && MI.getOperand(0).getSubReg() && MI.readsVirtualRegister(DefReg)) return false; // Avoid instructions obviously unsafe for remat. if (MI.isNotDuplicable() || MI.mayStore() || MI.hasUnmodeledSideEffects()) return false; // Don't remat inline asm. We have no idea how expensive it is // even if it's side effect free. if (MI.isInlineAsm()) return false; } We have following doubts and require guidance and suggestion to move ahead...

..., 2011 2:33 PM To: Dmitry Denisenko Cc: llvmdev at cs.uiuc.edu Subject: Re: [LLVMdev] How to prevent duplication of function calls? This came up a long time ago, but I'm not sure what the resolution was: http://lists.cs.uiuc.edu/pipermail/llvmdev/2009-October/026312.html There's also TID::isNotDuplicable: http://llvm.org/docs/doxygen/html/classllvm_1_1TargetInstrDesc.html#ab05b074805f22503828b5b625d437f3a I don't know enough about LLVM's backend to say if you can get that on an intrinsic. Reid On Thu, Apr 14, 2011 at 5:24 PM, Dmitry Denisenko <DDENISEN at altera.com> wrote: > He...

Hello, Is it possible to prevent duplication of call sites for specific functions (while still maintaining -O3 optimization level)? For example, the following C code: ------------------ if (cond1) a=2; llvm.memory.barrier(...); ------------------ is turned by clang with -O2 into something like this: ------------------ if (cond1) a=2; llvm.memory.barrier(...); else

...> Cc: llvmdev at cs.uiuc.edu > Subject: Re: [LLVMdev] How to prevent duplication of function calls? > > This came up a long time ago, but I'm not sure what the resolution was: > http://lists.cs.uiuc.edu/pipermail/llvmdev/2009-October/026312.html > > There's also TID::isNotDuplicable: > http://llvm.org/docs/doxygen/html/classllvm_1_1TargetInstrDesc.html#ab0 > 5b074805f22503828b5b625d437f3a > > I don't know enough about LLVM's backend to say if you can get that on > an intrinsic. > > Reid > > On Thu, Apr 14, 2011 at 5:24 PM, Dmitry Denisenko...

...ss = 0; // see question 1 bit isCommutable = 0; // see rq1 below bit isTerminator = 0; // terminate what? A BB, A function, or the program bit isReMaterializable = 0; // ? bit isPredicable = 0; bit hasDelaySlot = 0; bit usesCustomDAGSchedInserter = 0; bit hasCtrlDep = 0; // ? bit isNotDuplicable = 0; // ? bit hasSideEffects = 0; bit mayHaveSideEffects = 0; // how is this different from has side effect? bit neverHasSideEffects = 1; Rq1: If I have a instruction 'add reg, imm' and don't have 'add imm, reg' I suppose the instruction isn't commutable? 3) For con...

On Wed, Oct 31, 2012 at 09:13:43PM +0100, Bjorn De Sutter wrote: > Hi all, > > I am working on a CGRA backend (something like a 2D VLIW), and we also absolutely need predication. I extended the IfConversion pass to allow it to be executed multiple times and to predicate already predicated code. This is necessary to predicate code with nested conditional statements. At this point, we

Hi all, I am working on a CGRA backend (something like a 2D VLIW), and we also absolutely need predication. I extended the IfConversion pass to allow it to be executed multiple times and to predicate already predicated code. This is necessary to predicate code with nested conditional statements. At this point, we support or, and, and conditional predicates (see Scott Mahlke's papers on this