diff options
Diffstat (limited to 'llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp index 697bc1b448d..97a61bd0d78 100644 --- a/llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp +++ b/llvm/lib/Transforms/Vectorize/LoopVectorizationLegality.cpp @@ -434,8 +434,10 @@ static Type *getWiderType(const DataLayout &DL, Type *Ty0, Type *Ty1) { /// identified reduction variable. static bool hasOutsideLoopUser(const Loop *TheLoop, Instruction *Inst, SmallPtrSetImpl<Value *> &AllowedExit) { - // Reduction and Induction instructions are allowed to have exit users. All + // Reductions, Inductions and non-header phis are allowed to have exit users. All // other instructions must not have external users. + // TODO: Non-phi instructions can also be taught to have exit users, now that + // we know how to extract the last scalar element from the loop. if (!AllowedExit.count(Inst)) // Check that all of the users of the loop are inside the BB. for (User *U : Inst->users()) { @@ -597,14 +599,12 @@ bool LoopVectorizationLegality::canVectorizeInstrs() { // can convert it to select during if-conversion. No need to check if // the PHIs in this block are induction or reduction variables. if (BB != Header) { - // Check that this instruction has no outside users or is an - // identified reduction value with an outside user. - if (!hasOutsideLoopUser(TheLoop, Phi, AllowedExit)) - continue; - ORE->emit(createMissedAnalysis("NeitherInductionNorReduction", Phi) - << "value could not be identified as " - "an induction or reduction variable"); - return false; + // Non-header phi nodes that have outside uses can be vectorized. Add + // them to the list of allowed exits. + // Unsafe cyclic dependencies with header phis are identified during + // legalization for reduction, induction and first order + // recurrences. + continue; } // We only allow if-converted PHIs with exactly two incoming values. |
