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lib/Analysis/ScalarEvolution.cpp
- This file is larger than 256 KB, so syntax highlighting is disabled by default.
| Show First 20 Lines • Show All 3,945 Lines • ▼ Show 20 Lines | if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(BEValue)) { | ||||
| // This is not a valid addrec if the step amount is varying each | // This is not a valid addrec if the step amount is varying each | ||||
| // loop iteration, but is not itself an addrec in this loop. | // loop iteration, but is not itself an addrec in this loop. | ||||
| if (isLoopInvariant(Accum, L) || | if (isLoopInvariant(Accum, L) || | ||||
| (isa<SCEVAddRecExpr>(Accum) && | (isa<SCEVAddRecExpr>(Accum) && | ||||
| cast<SCEVAddRecExpr>(Accum)->getLoop() == L)) { | cast<SCEVAddRecExpr>(Accum)->getLoop() == L)) { | ||||
| SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap; | SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap; | ||||
| // If the increment doesn't overflow, then neither the addrec nor | |||||
| // the post-increment will overflow. | |||||
| if (auto BO = MatchBinaryOp(BEValueV)) { | if (auto BO = MatchBinaryOp(BEValueV)) { | ||||
| if (BO->Opcode == Instruction::Add && BO->LHS == PN) { | if (BO->Opcode == Instruction::Add && BO->LHS == PN) { | ||||
| if (BO->IsNUW) | if (BO->IsNUW) | ||||
| Flags = setFlags(Flags, SCEV::FlagNUW); | Flags = setFlags(Flags, SCEV::FlagNUW); | ||||
| if (BO->IsNSW) | if (BO->IsNSW) | ||||
| Flags = setFlags(Flags, SCEV::FlagNSW); | Flags = setFlags(Flags, SCEV::FlagNSW); | ||||
| } | } | ||||
| } else if (GEPOperator *GEP = dyn_cast<GEPOperator>(BEValueV)) { | } else if (GEPOperator *GEP = dyn_cast<GEPOperator>(BEValueV)) { | ||||
| Show All 14 Lines | if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(BEValue)) { | ||||
| // We cannot transfer nuw and nsw flags from subtraction | // We cannot transfer nuw and nsw flags from subtraction | ||||
| // operations -- sub nuw X, Y is not the same as add nuw X, -Y | // operations -- sub nuw X, Y is not the same as add nuw X, -Y | ||||
| // for instance. | // for instance. | ||||
| } | } | ||||
| const SCEV *StartVal = getSCEV(StartValueV); | const SCEV *StartVal = getSCEV(StartValueV); | ||||
| const SCEV *PHISCEV = getAddRecExpr(StartVal, Accum, L, Flags); | const SCEV *PHISCEV = getAddRecExpr(StartVal, Accum, L, Flags); | ||||
| // Since the no-wrap flags are on the increment, they apply to the | |||||
| // post-incremented value as well. | |||||
| if (isLoopInvariant(Accum, L)) | |||||
| (void)getAddRecExpr(getAddExpr(StartVal, Accum), Accum, L, Flags); | |||||
| // Okay, for the entire analysis of this edge we assumed the PHI | // Okay, for the entire analysis of this edge we assumed the PHI | ||||
| // to be symbolic. We now need to go back and purge all of the | // to be symbolic. We now need to go back and purge all of the | ||||
| // entries for the scalars that use the symbolic expression. | // entries for the scalars that use the symbolic expression. | ||||
| forgetSymbolicName(PN, SymbolicName); | forgetSymbolicName(PN, SymbolicName); | ||||
| ValueExprMap[SCEVCallbackVH(PN, this)] = PHISCEV; | ValueExprMap[SCEVCallbackVH(PN, this)] = PHISCEV; | ||||
| // We can add Flags to the post-inc expression only if we | |||||
hfinkel: Indentation looks odd here. | |||||
| // know that it us *undefined behavior* for BEValueV to | |||||
| // overflow. | |||||
| if (auto *BEInst = dyn_cast<Instruction>(BEValueV)) | |||||
| if (isLoopInvariant(Accum, L) && isSCEVExprNeverPoison(BEInst)) | |||||
| (void)getAddRecExpr(getAddExpr(StartVal, Accum), Accum, L, Flags); | |||||
| return PHISCEV; | return PHISCEV; | ||||
| } | } | ||||
| } | } | ||||
| } else { | } else { | ||||
| // Otherwise, this could be a loop like this: | // Otherwise, this could be a loop like this: | ||||
| // i = 0; for (j = 1; ..; ++j) { .... i = j; } | // i = 0; for (j = 1; ..; ++j) { .... i = j; } | ||||
| // In this case, j = {1,+,1} and BEValue is j. | // In this case, j = {1,+,1} and BEValue is j. | ||||
| // Because the other in-value of i (0) fits the evolution of BEValue | // Because the other in-value of i (0) fits the evolution of BEValue | ||||
| ▲ Show 20 Lines • Show All 6,393 Lines • Show Last 20 Lines | |||||
Indentation looks odd here.