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-rw-r--r--contrib/llvm/lib/Analysis/ScalarEvolutionExpander.cpp145
1 files changed, 70 insertions, 75 deletions
diff --git a/contrib/llvm/lib/Analysis/ScalarEvolutionExpander.cpp b/contrib/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
index fcd7ce272a22..86a557b55f7e 100644
--- a/contrib/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/contrib/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -14,6 +14,7 @@
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/ScalarEvolutionExpander.h"
+#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
@@ -176,8 +177,8 @@ Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode,
}
// Save the original insertion point so we can restore it when we're done.
- BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
- BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+ DebugLoc Loc = Builder.GetInsertPoint()->getDebugLoc();
+ BuilderType::InsertPointGuard Guard(Builder);
// Move the insertion point out of as many loops as we can.
while (const Loop *L = SE.LI->getLoopFor(Builder.GetInsertBlock())) {
@@ -191,13 +192,9 @@ Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode,
// If we haven't found this binop, insert it.
Instruction *BO = cast<Instruction>(Builder.CreateBinOp(Opcode, LHS, RHS));
- BO->setDebugLoc(SaveInsertPt->getDebugLoc());
+ BO->setDebugLoc(Loc);
rememberInstruction(BO);
- // Restore the original insert point.
- if (SaveInsertBB)
- restoreInsertPoint(SaveInsertBB, SaveInsertPt);
-
return BO;
}
@@ -294,8 +291,8 @@ static bool FactorOutConstant(const SCEV *&S,
const SCEV *Start = A->getStart();
if (!FactorOutConstant(Start, Remainder, Factor, SE, TD))
return false;
- // FIXME: can use A->getNoWrapFlags(FlagNW)
- S = SE.getAddRecExpr(Start, Step, A->getLoop(), SCEV::FlagAnyWrap);
+ S = SE.getAddRecExpr(Start, Step, A->getLoop(),
+ A->getNoWrapFlags(SCEV::FlagNW));
return true;
}
@@ -348,8 +345,7 @@ static void SplitAddRecs(SmallVectorImpl<const SCEV *> &Ops,
AddRecs.push_back(SE.getAddRecExpr(Zero,
A->getStepRecurrence(SE),
A->getLoop(),
- // FIXME: A->getNoWrapFlags(FlagNW)
- SCEV::FlagAnyWrap));
+ A->getNoWrapFlags(SCEV::FlagNW)));
if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Start)) {
Ops[i] = Zero;
Ops.append(Add->op_begin(), Add->op_end());
@@ -407,6 +403,10 @@ Value *SCEVExpander::expandAddToGEP(const SCEV *const *op_begin,
// without the other.
SplitAddRecs(Ops, Ty, SE);
+ Type *IntPtrTy = SE.TD
+ ? SE.TD->getIntPtrType(PTy)
+ : Type::getInt64Ty(PTy->getContext());
+
// Descend down the pointer's type and attempt to convert the other
// operands into GEP indices, at each level. The first index in a GEP
// indexes into the array implied by the pointer operand; the rest of
@@ -417,7 +417,7 @@ Value *SCEVExpander::expandAddToGEP(const SCEV *const *op_begin,
// array indexing.
SmallVector<const SCEV *, 8> ScaledOps;
if (ElTy->isSized()) {
- const SCEV *ElSize = SE.getSizeOfExpr(ElTy);
+ const SCEV *ElSize = SE.getSizeOfExpr(IntPtrTy, ElTy);
if (!ElSize->isZero()) {
SmallVector<const SCEV *, 8> NewOps;
for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
@@ -549,8 +549,7 @@ Value *SCEVExpander::expandAddToGEP(const SCEV *const *op_begin,
}
// Save the original insertion point so we can restore it when we're done.
- BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
- BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+ BuilderType::InsertPointGuard Guard(Builder);
// Move the insertion point out of as many loops as we can.
while (const Loop *L = SE.LI->getLoopFor(Builder.GetInsertBlock())) {
@@ -566,16 +565,11 @@ Value *SCEVExpander::expandAddToGEP(const SCEV *const *op_begin,
Value *GEP = Builder.CreateGEP(V, Idx, "uglygep");
rememberInstruction(GEP);
- // Restore the original insert point.
- if (SaveInsertBB)
- restoreInsertPoint(SaveInsertBB, SaveInsertPt);
-
return GEP;
}
// Save the original insertion point so we can restore it when we're done.
- BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
- BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+ BuilderType::InsertPoint SaveInsertPt = Builder.saveIP();
// Move the insertion point out of as many loops as we can.
while (const Loop *L = SE.LI->getLoopFor(Builder.GetInsertBlock())) {
@@ -611,8 +605,7 @@ Value *SCEVExpander::expandAddToGEP(const SCEV *const *op_begin,
rememberInstruction(GEP);
// Restore the original insert point.
- if (SaveInsertBB)
- restoreInsertPoint(SaveInsertBB, SaveInsertPt);
+ Builder.restoreIP(SaveInsertPt);
return expand(SE.getAddExpr(Ops));
}
@@ -846,8 +839,7 @@ static void ExposePointerBase(const SCEV *&Base, const SCEV *&Rest,
SE.getAddRecExpr(SE.getConstant(A->getType(), 0),
A->getStepRecurrence(SE),
A->getLoop(),
- // FIXME: A->getNoWrapFlags(FlagNW)
- SCEV::FlagAnyWrap));
+ A->getNoWrapFlags(SCEV::FlagNW)));
}
if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(Base)) {
Base = A->getOperand(A->getNumOperands()-1);
@@ -1078,8 +1070,7 @@ SCEVExpander::getAddRecExprPHILiterally(const SCEVAddRecExpr *Normalized,
}
// Save the original insertion point so we can restore it when we're done.
- BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
- BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+ BuilderType::InsertPointGuard Guard(Builder);
// Another AddRec may need to be recursively expanded below. For example, if
// this AddRec is quadratic, the StepV may itself be an AddRec in this
@@ -1137,14 +1128,15 @@ SCEVExpander::getAddRecExprPHILiterally(const SCEVAddRecExpr *Normalized,
IVIncInsertPos : Pred->getTerminator();
Builder.SetInsertPoint(InsertPos);
Value *IncV = expandIVInc(PN, StepV, L, ExpandTy, IntTy, useSubtract);
-
+ if (isa<OverflowingBinaryOperator>(IncV)) {
+ if (Normalized->getNoWrapFlags(SCEV::FlagNUW))
+ cast<BinaryOperator>(IncV)->setHasNoUnsignedWrap();
+ if (Normalized->getNoWrapFlags(SCEV::FlagNSW))
+ cast<BinaryOperator>(IncV)->setHasNoSignedWrap();
+ }
PN->addIncoming(IncV, Pred);
}
- // Restore the original insert point.
- if (SaveInsertBB)
- restoreInsertPoint(SaveInsertBB, SaveInsertPt);
-
// After expanding subexpressions, restore the PostIncLoops set so the caller
// can ensure that IVIncrement dominates the current uses.
PostIncLoops = SavedPostIncLoops;
@@ -1180,8 +1172,7 @@ Value *SCEVExpander::expandAddRecExprLiterally(const SCEVAddRecExpr *S) {
Normalized = cast<SCEVAddRecExpr>(
SE.getAddRecExpr(Start, Normalized->getStepRecurrence(SE),
Normalized->getLoop(),
- // FIXME: Normalized->getNoWrapFlags(FlagNW)
- SCEV::FlagAnyWrap));
+ Normalized->getNoWrapFlags(SCEV::FlagNW)));
}
// Strip off any non-loop-dominating component from the addrec step.
@@ -1191,11 +1182,9 @@ Value *SCEVExpander::expandAddRecExprLiterally(const SCEVAddRecExpr *S) {
PostLoopScale = Step;
Step = SE.getConstant(Normalized->getType(), 1);
Normalized =
- cast<SCEVAddRecExpr>(SE.getAddRecExpr(Start, Step,
- Normalized->getLoop(),
- // FIXME: Normalized
- // ->getNoWrapFlags(FlagNW)
- SCEV::FlagAnyWrap));
+ cast<SCEVAddRecExpr>(SE.getAddRecExpr(
+ Start, Step, Normalized->getLoop(),
+ Normalized->getNoWrapFlags(SCEV::FlagNW)));
}
// Expand the core addrec. If we need post-loop scaling, force it to
@@ -1232,19 +1221,19 @@ Value *SCEVExpander::expandAddRecExprLiterally(const SCEVAddRecExpr *S) {
!ExpandTy->isPointerTy() && Step->isNonConstantNegative();
if (useSubtract)
Step = SE.getNegativeSCEV(Step);
- // Expand the step somewhere that dominates the loop header.
- BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
- BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
- Value *StepV = expandCodeFor(Step, IntTy, L->getHeader()->begin());
- // Restore the insertion point to the place where the caller has
- // determined dominates all uses.
- restoreInsertPoint(SaveInsertBB, SaveInsertPt);
+ Value *StepV;
+ {
+ // Expand the step somewhere that dominates the loop header.
+ BuilderType::InsertPointGuard Guard(Builder);
+ StepV = expandCodeFor(Step, IntTy, L->getHeader()->begin());
+ }
Result = expandIVInc(PN, StepV, L, ExpandTy, IntTy, useSubtract);
}
}
// Re-apply any non-loop-dominating scale.
if (PostLoopScale) {
+ assert(S->isAffine() && "Can't linearly scale non-affine recurrences.");
Result = InsertNoopCastOfTo(Result, IntTy);
Result = Builder.CreateMul(Result,
expandCodeFor(PostLoopScale, IntTy));
@@ -1288,18 +1277,15 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
for (unsigned i = 0, e = S->getNumOperands(); i != e; ++i)
NewOps[i] = SE.getAnyExtendExpr(S->op_begin()[i], CanonicalIV->getType());
Value *V = expand(SE.getAddRecExpr(NewOps, S->getLoop(),
- // FIXME: S->getNoWrapFlags(FlagNW)
- SCEV::FlagAnyWrap));
- BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
- BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+ S->getNoWrapFlags(SCEV::FlagNW)));
BasicBlock::iterator NewInsertPt =
llvm::next(BasicBlock::iterator(cast<Instruction>(V)));
+ BuilderType::InsertPointGuard Guard(Builder);
while (isa<PHINode>(NewInsertPt) || isa<DbgInfoIntrinsic>(NewInsertPt) ||
isa<LandingPadInst>(NewInsertPt))
++NewInsertPt;
V = expandCodeFor(SE.getTruncateExpr(SE.getUnknown(V), Ty), 0,
NewInsertPt);
- restoreInsertPoint(SaveInsertBB, SaveInsertPt);
return V;
}
@@ -1307,8 +1293,8 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
if (!S->getStart()->isZero()) {
SmallVector<const SCEV *, 4> NewOps(S->op_begin(), S->op_end());
NewOps[0] = SE.getConstant(Ty, 0);
- // FIXME: can use S->getNoWrapFlags()
- const SCEV *Rest = SE.getAddRecExpr(NewOps, L, SCEV::FlagAnyWrap);
+ const SCEV *Rest = SE.getAddRecExpr(NewOps, L,
+ S->getNoWrapFlags(SCEV::FlagNW));
// Turn things like ptrtoint+arithmetic+inttoptr into GEP. See the
// comments on expandAddToGEP for details.
@@ -1343,9 +1329,13 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
Header->begin());
rememberInstruction(CanonicalIV);
+ SmallSet<BasicBlock *, 4> PredSeen;
Constant *One = ConstantInt::get(Ty, 1);
for (pred_iterator HPI = HPB; HPI != HPE; ++HPI) {
BasicBlock *HP = *HPI;
+ if (!PredSeen.insert(HP))
+ continue;
+
if (L->contains(HP)) {
// Insert a unit add instruction right before the terminator
// corresponding to the back-edge.
@@ -1528,8 +1518,7 @@ Value *SCEVExpander::expand(const SCEV *S) {
if (I != InsertedExpressions.end())
return I->second;
- BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
- BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+ BuilderType::InsertPointGuard Guard(Builder);
Builder.SetInsertPoint(InsertPt->getParent(), InsertPt);
// Expand the expression into instructions.
@@ -1542,8 +1531,6 @@ Value *SCEVExpander::expand(const SCEV *S) {
// a postinc expansion, it could be reused by a non postinc user, but only if
// its insertion point was already at the head of the loop.
InsertedExpressions[std::make_pair(S, InsertPt)] = V;
-
- restoreInsertPoint(SaveInsertBB, SaveInsertPt);
return V;
}
@@ -1554,10 +1541,6 @@ void SCEVExpander::rememberInstruction(Value *I) {
InsertedValues.insert(I);
}
-void SCEVExpander::restoreInsertPoint(BasicBlock *BB, BasicBlock::iterator I) {
- Builder.SetInsertPoint(BB, I);
-}
-
/// getOrInsertCanonicalInductionVariable - This method returns the
/// canonical induction variable of the specified type for the specified
/// loop (inserting one if there is none). A canonical induction variable
@@ -1573,11 +1556,8 @@ SCEVExpander::getOrInsertCanonicalInductionVariable(const Loop *L,
SE.getConstant(Ty, 1), L, SCEV::FlagAnyWrap);
// Emit code for it.
- BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
- BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+ BuilderType::InsertPointGuard Guard(Builder);
PHINode *V = cast<PHINode>(expandCodeFor(H, 0, L->getHeader()->begin()));
- if (SaveInsertBB)
- restoreInsertPoint(SaveInsertBB, SaveInsertPt);
return V;
}
@@ -1725,28 +1705,43 @@ namespace {
// Currently, we only allow division by a nonzero constant here. If this is
// inadequate, we could easily allow division by SCEVUnknown by using
// ValueTracking to check isKnownNonZero().
+//
+// We cannot generally expand recurrences unless the step dominates the loop
+// header. The expander handles the special case of affine recurrences by
+// scaling the recurrence outside the loop, but this technique isn't generally
+// applicable. Expanding a nested recurrence outside a loop requires computing
+// binomial coefficients. This could be done, but the recurrence has to be in a
+// perfectly reduced form, which can't be guaranteed.
struct SCEVFindUnsafe {
+ ScalarEvolution &SE;
bool IsUnsafe;
- SCEVFindUnsafe(): IsUnsafe(false) {}
+ SCEVFindUnsafe(ScalarEvolution &se): SE(se), IsUnsafe(false) {}
bool follow(const SCEV *S) {
- const SCEVUDivExpr *D = dyn_cast<SCEVUDivExpr>(S);
- if (!D)
- return true;
- const SCEVConstant *SC = dyn_cast<SCEVConstant>(D->getRHS());
- if (SC && !SC->getValue()->isZero())
- return true;
- IsUnsafe = true;
- return false;
+ if (const SCEVUDivExpr *D = dyn_cast<SCEVUDivExpr>(S)) {
+ const SCEVConstant *SC = dyn_cast<SCEVConstant>(D->getRHS());
+ if (!SC || SC->getValue()->isZero()) {
+ IsUnsafe = true;
+ return false;
+ }
+ }
+ if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
+ const SCEV *Step = AR->getStepRecurrence(SE);
+ if (!AR->isAffine() && !SE.dominates(Step, AR->getLoop()->getHeader())) {
+ IsUnsafe = true;
+ return false;
+ }
+ }
+ return true;
}
bool isDone() const { return IsUnsafe; }
};
}
namespace llvm {
-bool isSafeToExpand(const SCEV *S) {
- SCEVFindUnsafe Search;
+bool isSafeToExpand(const SCEV *S, ScalarEvolution &SE) {
+ SCEVFindUnsafe Search(SE);
visitAll(S, Search);
return !Search.IsUnsafe;
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-03-06 14:33:07 +0000