search for: hasnounsignedwrap

...'clearTopDownPointers' function is fully equivalent to the body of 'clearBottomUpPointers' function. The advised solution is to change this code into void clearBottomUpPointers() {     PerPtrBottomUp.clear(); } ---- lib/Analysis/InstructionSimplify.cpp:1891     bool NUW = LBO->hasNoUnsignedWrap() && LBO->hasNoUnsignedWrap(); There are identical sub-expressions 'LBO->hasNoUnsignedWrap()' to the left and to the right of the '&&' operator. Looks like the correct code is     bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();...

...function. The advised solution is to change > this code into > > void clearBottomUpPointers() { > PerPtrBottomUp.clear(); > } This is probably correct. Hopefully John can comment. > > ---- > > lib/Analysis/InstructionSimplify.cpp:1891 > bool NUW = LBO->hasNoUnsignedWrap()&& LBO->hasNoUnsignedWrap(); > > There are identical sub-expressions 'LBO->hasNoUnsignedWrap()' to the left and > to the right of the '&&' operator. Looks like the correct code is > > bool NUW = LBO->hasNoUnsignedWrap()&& RBO-&...

...the flags NSW/NUW are set according to the Operator BEValueV (ScalarEvoluton.cpp:3099-3113), but only Add and GEP operators are checked. //-------------------------------------------------------------------------// if (const AddOperator *OBO = dyn_cast<AddOperator>(BEValueV)) { if (OBO->hasNoUnsignedWrap()) Flags = setFlags(Flags, SCEV::FlagNUW); if (OBO->hasNoSignedWrap()) Flags = setFlags(Flags, SCEV::FlagNSW); } else if (const GEPOperator *GEP = dyn_cast<GEPOperator>(BEValueV)) { // If the increment is an inbounds GEP, then we know the address // space cannot...

...R/Instructions.cpp&ct=xref_jump_to_def&cl=GROK&l=2025&gsn=hasNoSignedWrap>()); Res <https://cs.corp.google.com/#piper///depot/google3/third_party/llvm/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp&ct=xref_jump_to_def&cl=GROK&l=1471&gsn=Res>->setHasNoUnsignedWrap <https://cs.corp.google.com/#piper///depot/google3/third_party/llvm/llvm/lib/IR/Instructions.cpp&ct=xref_jump_to_def&cl=GROK&l=2009&gsn=setHasNoUnsignedWrap>(I <https://cs.corp.google.com/#piper///depot/google3/third_party/llvm/llvm/lib/Transforms/InstCombine/InstCombineAdd...

...t according to the Operator BEValueV > (ScalarEvoluton.cpp:3099-3113), but only Add and GEP operators are checked. > > //-------------------------------------------------------------------------// > if (const AddOperator *OBO = dyn_cast<AddOperator>(BEValueV)) { > if (OBO->hasNoUnsignedWrap()) > Flags = setFlags(Flags, SCEV::FlagNUW); > if (OBO->hasNoSignedWrap()) > Flags = setFlags(Flags, SCEV::FlagNSW); > } else if (const GEPOperator *GEP = > dyn_cast<GEPOperator>(BEValueV)) { > // If the increment is an inbounds GEP, then we know the a...

...it shifts out only zeros, but the result has the sign bit set) but "mul i8 1, i8 -128" does not sign overflow (by the usual definition of sign-overflow), so this violates (2). InstCombine already has a check for this edge-case when folding multiplies into left shifts: ... if (I.hasNoUnsignedWrap()) Shl->setHasNoUnsignedWrap(); if (I.hasNoSignedWrap() && *** NewCst->isNotMinSignedValue() ***) Shl->setHasNoSignedWrap(); ... (though the check is a bit weird -- NewCst is Log2(IVal) so I think it cannot ever be INT_MIN, and I suspect that the check...

...gt; var = var + y > > So I want to read all parameters of the instruction, like the var name, the number, the type,... Parameters (operands): Add->getOperand(n) (for n = 0, 1, ... , Add->getNumOperands()). A few other "parameters" like nuw/nsw/exact can be accessed as Add->hasNoUnsignedWrap()/setHasNoUnsignedWrap() and friends. Var name: Add->getName() / Add->setName(). Can efficiently be transfered to the new instruction with Sub->takeName(Add). The number is automatically assigned if it doesn't have a name. I'm not sure if there's an easy way to determine it ot...

...V > > (ScalarEvoluton.cpp:3099-3113), but only Add and GEP operators are > > checked. > > > > //-------------------------------------------------------------------------// > > if (const AddOperator *OBO = dyn_cast<AddOperator>(BEValueV)) { > > if (OBO->hasNoUnsignedWrap()) > > Flags = setFlags(Flags, SCEV::FlagNUW); > > if (OBO->hasNoSignedWrap()) > > Flags = setFlags(Flags, SCEV::FlagNSW); > > } else if (const GEPOperator *GEP = > > dyn_cast<GEPOperator>(BEValueV)) { > > // If the increment is an in...

Hi, I have a question about the llvm passes. I'm iterating over a basicblock and I can get an instruction and print it. Now, I want to iterate over the instruction and be able to modify the values of the instruction. For example, if my instruction is an add "<result> = add i32 4, %var" I want to transform it in a sub "<result> = sub i32 4, %var". I looked up

I've been doing some digging in this area (scev, wrapping arithmetic), learning as much as I can, and have reached a point where I'm fairly confused about the semantics of nuw in scalar evolution expressions. Consider the following program: define void @foo(i32 %begin) { entry: br label %loop loop: %idx = phi i32 [ %begin, %entry ], [ %idx.dec, %loop ] %idx.dec = sub nuw i32