search for: replaceinstuseswith

...o the instcombine pass. We'd need IR enhancements to do this sort of thing for real in the mid-level optimizer, some thoughts are here: > http://nondot.org/sabre/LLVMNotes/FloatingPointChanges.txt > Thanks, now it works. I inserted if (Op1F->isNullValue()) return ReplaceInstUsesWith(I, Op1C); // X * 0 == 0 into llvm::InstCombiner::visitFMul Why not at first create a compile time option for this so that the code is already available for special purposes? -Jochen

...reachable. We do this instead of inserting 09796 // an unreachable instruction directly because we cannot modify the 09797 // CFG. 09798 new StoreInst(UndefValue::get(LI.getType()), 09799 Constant::getNullValue(Op->getType()), &LI); 09800 return ReplaceInstUsesWith(LI, UndefValue::get(LI.getType())); 09801 } 09802 } First, what happens to the StoreInst? It looks like it is not attached anywhere. Second, I am seeing this happen in a block that is definitely reachable. Later on the null GEP is removed because it isInstructionTriviallyDead. But the un...

...// that this code is not reachable. We do this instead of inserting // an unreachable instruction directly because we cannot modify the // CFG. new StoreInst(UndefValue::get(LI.getType()), Constant::getNullValue(Op->getType()), &LI); return ReplaceInstUsesWith(LI, UndefValue::get(LI.getType())); } } > > Thanks, > -- Sanjoy > > On Thu, Dec 4, 2014 at 10:09 PM, Sanjoy Das > <sanjoy at playingwithpointers.com> wrote: >> Is copy.0 semantically equivalent to copy.1 in the following example? >> >> define void...

> You should check out the -enable-finite-only-fp-math and -enable-unsafe-fp-math options. Good hint, but llvm::UnsafeFPMath = true; llvm::FiniteOnlyFPMathOption = true; at the beginning of my code does not help. I found llvm::Reassociate::OptimizeExpression in llvm\lib\Transforms\Scalar\Reassociate.cpp which looks like it does X * 0 = 0 for int, but it does not get called for

On Mar 3, 2010, at 10:23 AM, Jochen Wilhelmy wrote: > >> You should check out the -enable-finite-only-fp-math and -enable-unsafe-fp-math options. > > Good hint, but > > llvm::UnsafeFPMath = true; > llvm::FiniteOnlyFPMathOption = true; > > at the beginning of my code does not help. > I found llvm::Reassociate::OptimizeExpression in >

...#39;d need IR enhancements to do this sort of thing for real in the mid-level optimizer, some thoughts are here: >> http://nondot.org/sabre/LLVMNotes/FloatingPointChanges.txt >> > > Thanks, now it works. I inserted > > if (Op1F->isNullValue()) > return ReplaceInstUsesWith(I, Op1C); // X * 0 == 0 > > into llvm::InstCombiner::visitFMul > > Why not at first create a compile time option for this so that the > code is already available for special purposes? I'm not sure how that would work, but it most likely wouldn't fit with the design of ll...

Hello, My name is Siddharth. I’m a student studying math and computer science at the University of Toronto. I’m interested in learning more about the LLVM compiler through GSoC. I have no prior experience with LLVM, but I have a strong interest in compilers, and I look forward to learning more. I would like to pursue one of two potential projects: rewriting bugpoint, and moving optimizations

...> inserting > 09796 // an unreachable instruction directly because we cannot modify > the > 09797 // CFG. > 09798 new StoreInst(UndefValue::get(LI.getType()), > 09799 Constant::getNullValue(Op->getType()), &LI); > 09800 return ReplaceInstUsesWith(LI, UndefValue::get(LI.getType())); > 09801 } > 09802 } > > First, what happens to the StoreInst? It looks like it is not attached > anywhere. The &LI argument causes it to be inserted before the load. > Second, I am seeing this happen in a block that is definitely re...

...ne scrutinizing the logic for >> correctness. >> >> --- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original) >> +++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Mon Jan 4 00:03:59 2010 >> @@ -5213,12 +5213,30 @@ >> return ReplaceInstUsesWith(I, B); >> } >> } >> - V1 = 0; V2 = 0; V3 = 0; >> + >> + // ((V | N) & C1) | (V & C2) --> (V|N) & (C1|C2) >> + // iff (C1&C2) == 0 and (N&~C1) == 0 >> + if ((C1->getValue() & C2->getValue...

Is copy.0 semantically equivalent to copy.1 in the following example? define void @copy.0(i8 addrspace(1)* addrspace(1)* %src, i8 addrspace(1)* addrspace(1)* %dst) { entry: %val = load i8 addrspace(1)* addrspace(1)* %src store i8 addrspace(1)* %val, i8 addrspace(1)* addrspace(1)* %dst ret void } define void @copy.1(i8 addrspace(1)* addrspace(1)* %src, i8 addrspace(1)* addrspace(1)* %dst)

...t as well. We couldn't do this before, because the + // above two lines don't hold for the GEPs + const Type* GEPTy = PointerType::get(GEP->getType()->getElementType(), DestTy->getAddressSpace()); + ReplaceWith = InsertBitCastBefore(NewInst, GEPTy, *GEP); + } + ReplaceInstUsesWith(*OldInst, ReplaceWith); + EraseInstFromFunction(*OldInst); + + } + + // Return the old instruction, so it can be removed. + return &CI; +} + Instruction *InstCombiner::visitBitCast(BitCastInst &CI) { // If the operands are integer typed then apply the integer transforms, // o...

> On Jul 6, 2017, at 3:07 PM, Chris Lattner <clattner at nondot.org> wrote: > > >> On Jul 6, 2017, at 2:05 PM, Peter Lawrence via llvm-dev <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote: >> >> >>> On Jul 6, 2017, at 1:00 PM, via llvm-dev <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>>

...re, > because the > + // above two lines don't hold for the GEPs > + const Type* GEPTy = PointerType::get(GEP->getType()- > >getElementType(), DestTy->getAddressSpace()); > + ReplaceWith = InsertBitCastBefore(NewInst, GEPTy, *GEP); > + } > + ReplaceInstUsesWith(*OldInst, ReplaceWith); > + EraseInstFromFunction(*OldInst); > + > + } > + > + // Return the old instruction, so it can be removed. > + return &CI; > +} > + > Instruction *InstCombiner::visitBitCast(BitCastInst &CI) { > // If the operands are integer ty...

Hi Eli, Mon Ping, > In ISO/IEC WG14 n1169 on the C extensions to support embedded > processors, any two address spaces must be disjoint, must be > equivalent, or must be nested. Ah, that standard is a lot clearer on this subject than the DSP-C one I read was. > As Eli indicated, the actual relationship is platform specific depending on > what makes the most sense for

Hello, I have come across an unusual behavior where instruction domination rule is violated "Instruction does not dominate all its uses." It concerns with StackColoring pass present at llvm/lib/CodeGen/StackColoring.cpp. I am reaching out to the LLVM community to help me understand the cause of this issue and the working of the pass. The IR produced at the end of the pass seems to be

In ISO/IEC WG14 n1169 on the C extensions to support embedded processors, any two address spaces must be disjoint, must be equivalent, or must be nested. As Eli indicated, the actual relationship is platform specific depending on what makes the most sense for your hardware and how the program will behave will depend on that relationship. -- Mon Ping On Jul 17, 2008, at 7:25 AM, Eli