search for: vndag

...ev" > <llvm-dev at lists.llvm.org> > Sent: Wednesday, August 31, 2016 7:02:57 PM > Subject: Re: [llvm-dev] [RFC] Interprocedural MIR-level outlining > pass > (and in particular, the definition of equivalence used by code > folding to make the dags is STH like "two VNDAG expressions are > equivalent if their operands come from VNDAG expressions with the > same opcode") > Thus, > VN2 = VN0 + VN1 > VN3 = VN1 + VN2 > is considered equivalent to > VN2 = VN0 + VN5 > VN3 = VN1 + VN2 > Despite the fact that this is completely illegal f...

Daniel, OK, I see your point. My understanding was that VNDAG is an internal representation, not meant to be used by VN's customers (that should really care for classes of congruency, nothing more). Also, I thought that VN's results are available for a single function at a time. It seems that NewGVN provides access to VNDAGs computed for the whole pro...

> > > Yes, this was exactly my point. We want to recognize > structurally-equivalent sequences of instructions on inequivalent operands. > Yes, and my point is "none of the vn and vn-dag generating algorithms care". you can define equivalent to be "structural", you can define it to be "these two variables are equivalent if they both start with

...ev at lists.llvm.org> >> *Sent: *Wednesday, August 31, 2016 7:02:57 PM >> *Subject: *Re: [llvm-dev] [RFC] Interprocedural MIR-level outlining pass >> >> (and in particular, the definition of equivalence used by code folding to >> make the dags is STH like "two VNDAG expressions are equivalent if their >> operands come from VNDAG expressions with the same opcode") >> >> Thus, >> >> VN2 = VN0 + VN1 >> VN3 = VN1 + VN2 >> >> is considered equivalent to >> >> VN2 = VN0 + VN5 >> VN3 = VN1 + VN2 &...

...are abstract things". We > know if these abstract things are equivalent or not. > > More relevantly, these expressions form a value number dag. > > That is, they represent the computations being computed only in terms of > operators, abstract variables, and other parts of the VNDAG > > The *actual values* of those computations, numbers, etc, do not matter (IE > the abstract value numbers have some set of things *in the program* that > are in the set of things equivalent to that value number). > > It is "are these semantically the same operations in the...

----- Original Message ----- > From: "Daniel Berlin" <dberlin at dberlin.org> > To: "Quentin Colombet" <qcolombet at apple.com> > Cc: "Hal Finkel" <hfinkel at anl.gov>, "llvm-dev" > <llvm-dev at lists.llvm.org> > Sent: Friday, August 26, 2016 11:06:56 PM > Subject: Re: [llvm-dev] [RFC] Interprocedural MIR-level