[SCEV] Expose getGEPExpr without needing to pass GEPOperator* (NFC)

[fhahn]

Add a new getGEPExpr variant which is independent of GEPOperator*.

To be used to construct SCEVs for VPlan recipes in #161276.

[llvmbot]

@llvm/pr-subscribers-llvm-analysis

Author: Florian Hahn (fhahn)

Changes

Add a new getGEPExpr variant which is independent of GEPOperator*.

To be used to construct SCEVs for VPlan recipes in #161276.

---

Full diff: https://github.com/llvm/llvm-project/pull/164487.diff

2 Files Affected:

• (modified) llvm/include/llvm/Analysis/ScalarEvolution.h (+3)
• (modified) llvm/lib/Analysis/ScalarEvolution.cpp (+14-5)

diff --git a/llvm/include/llvm/Analysis/ScalarEvolution.h b/llvm/include/llvm/Analysis/ScalarEvolution.h index 3d3ec14796bc1..c419aed107464 100644 --- a/llvm/include/llvm/Analysis/ScalarEvolution.h +++ b/llvm/include/llvm/Analysis/ScalarEvolution.h @@ -640,6 +640,9 @@ class ScalarEvolution { /// \p IndexExprs The expressions for the indices. LLVM_ABI const SCEV * getGEPExpr(GEPOperator *GEP, const SmallVectorImpl<const SCEV *> &IndexExprs); + LLVM_ABI const SCEV *getGEPExpr( + const SCEV *BaseExpr, const SmallVectorImpl<const SCEV *> &IndexExprs, + Type *SrcElementTy, SCEV::NoWrapFlags OffsetWrap = SCEV::FlagAnyWrap); LLVM_ABI const SCEV *getAbsExpr(const SCEV *Op, bool IsNSW); LLVM_ABI const SCEV *getMinMaxExpr(SCEVTypes Kind, SmallVectorImpl<const SCEV *> &Operands); diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index 6f7dd79032cfe..4856c51ee2a4a 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -3774,7 +3774,6 @@ ScalarEvolution::getGEPExpr(GEPOperator *GEP, const SCEV *BaseExpr = getSCEV(GEP->getPointerOperand()); // getSCEV(Base)->getType() has the same address space as Base->getType() // because SCEV::getType() preserves the address space. - Type *IntIdxTy = getEffectiveSCEVType(BaseExpr->getType()); GEPNoWrapFlags NW = GEP->getNoWrapFlags(); if (NW != GEPNoWrapFlags::none()) { // We'd like to propagate flags from the IR to the corresponding SCEV nodes, @@ -3793,7 +3792,16 @@ ScalarEvolution::getGEPExpr(GEPOperator *GEP, if (NW.hasNoUnsignedWrap()) OffsetWrap = setFlags(OffsetWrap, SCEV::FlagNUW); - Type *CurTy = GEP->getType(); + return getGEPExpr(BaseExpr, IndexExprs, GEP->getSourceElementType(), + OffsetWrap); +} + +const SCEV * +ScalarEvolution::getGEPExpr(const SCEV *BaseExpr, + const SmallVectorImpl<const SCEV *> &IndexExprs, + Type *SrcElementTy, SCEV::NoWrapFlags OffsetWrap) { + Type *CurTy = BaseExpr->getType(); + Type *IntIdxTy = getEffectiveSCEVType(BaseExpr->getType()); bool FirstIter = true; SmallVector<const SCEV *, 4> Offsets; for (const SCEV *IndexExpr : IndexExprs) { @@ -3812,7 +3820,7 @@ ScalarEvolution::getGEPExpr(GEPOperator *GEP, if (FirstIter) { assert(isa<PointerType>(CurTy) && "The first index of a GEP indexes a pointer"); - CurTy = GEP->getSourceElementType(); + CurTy = SrcElementTy; FirstIter = false; } else { CurTy = GetElementPtrInst::getTypeAtIndex(CurTy, (uint64_t)0); @@ -3837,8 +3845,9 @@ ScalarEvolution::getGEPExpr(GEPOperator *GEP, // Add the base address and the offset. We cannot use the nsw flag, as the // base address is unsigned. However, if we know that the offset is // non-negative, we can use nuw. - bool NUW = NW.hasNoUnsignedWrap() || - (NW.hasNoUnsignedSignedWrap() && isKnownNonNegative(Offset)); + bool NUW = + hasFlags(OffsetWrap, SCEV::FlagNUW) || + (hasFlags(OffsetWrap, SCEV::FlagNSW) && isKnownNonNegative(Offset)); SCEV::NoWrapFlags BaseWrap = NUW ? SCEV::FlagNUW : SCEV::FlagAnyWrap; auto *GEPExpr = getAddExpr(BaseExpr, Offset, BaseWrap); assert(BaseExpr->getType() == GEPExpr->getType() && 

[artagnon]

LGTM, thanks! ArrayRef improvement is optional.

[nikic]

This should accept GEPNoWrapFlags instead of OffsetWrap. We should not infer the base wrapping behavior from the offset wrapping behavior.

[fhahn]

Updated, although currently I think the behavior currently stays the same, as OffsetWrap would be set to match the GEPNoWrapFlags (although with NSW instead of hasNoUnsignedSignedWrap)?

[nikic]

LGTM