[llvm-commits] [llvm] r44163 - in /llvm/trunk: include/llvm/Analysis/ScalarEvolution.h include/llvm/Analysis/ScalarEvolutionExpander.h include/llvm/Analysis/ScalarEvolutionExpressions.h lib/Analysis/ScalarEvolution.cpp test/Analysis/ScalarEvolution/2007-11-14-SignedAddRec.ll
Nick Lewycky
nicholas at mxc.ca
Wed Nov 14 22:30:50 PST 2007
Author: nicholas
Date: Thu Nov 15 00:30:50 2007
New Revision: 44163
URL: http://llvm.org/viewvc/llvm-project?rev=44163&view=rev
Log:
Fix handling of overflow in loop calculation by adding new UDiv SCEV. This SCEV
is disabled in the sense that it will refuse to create one from a UDiv
instruction, until the code is better tested.
Added:
llvm/trunk/test/Analysis/ScalarEvolution/2007-11-14-SignedAddRec.ll
Modified:
llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h
llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpressions.h
llvm/trunk/lib/Analysis/ScalarEvolution.cpp
Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolution.h?rev=44163&r1=44162&r2=44163&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolution.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolution.h Thu Nov 15 00:30:50 2007
@@ -226,6 +226,7 @@
return getMulExpr(Ops);
}
SCEVHandle getSDivExpr(const SCEVHandle &LHS, const SCEVHandle &RHS);
+ SCEVHandle getUDivExpr(const SCEVHandle &LHS, const SCEVHandle &RHS);
SCEVHandle getAddRecExpr(const SCEVHandle &Start, const SCEVHandle &Step,
const Loop *L);
SCEVHandle getAddRecExpr(std::vector<SCEVHandle> &Operands,
Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h?rev=44163&r1=44162&r2=44163&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h Thu Nov 15 00:30:50 2007
@@ -132,6 +132,12 @@
return InsertBinop(Instruction::SDiv, LHS, RHS, InsertPt);
}
+ Value *visitUDivExpr(SCEVUDivExpr *S) {
+ Value *LHS = expand(S->getLHS());
+ Value *RHS = expand(S->getRHS());
+ return InsertBinop(Instruction::UDiv, LHS, RHS, InsertPt);
+ }
+
Value *visitAddRecExpr(SCEVAddRecExpr *S);
Value *visitUnknown(SCEVUnknown *S) {
Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpressions.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpressions.h?rev=44163&r1=44162&r2=44163&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpressions.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpressions.h Thu Nov 15 00:30:50 2007
@@ -25,7 +25,7 @@
// These should be ordered in terms of increasing complexity to make the
// folders simpler.
scConstant, scTruncate, scZeroExtend, scSignExtend, scAddExpr, scMulExpr,
- scSDivExpr, scAddRecExpr, scUnknown, scCouldNotCompute
+ scSDivExpr, scUDivExpr, scAddRecExpr, scUnknown, scCouldNotCompute
};
//===--------------------------------------------------------------------===//
@@ -370,6 +370,55 @@
//===--------------------------------------------------------------------===//
+ /// SCEVUDivExpr - This class represents a binary unsigned division operation.
+ ///
+ class SCEVUDivExpr : public SCEV {
+ friend class ScalarEvolution;
+
+ SCEVHandle LHS, RHS;
+ SCEVUDivExpr(const SCEVHandle &lhs, const SCEVHandle &rhs)
+ : SCEV(scUDivExpr), LHS(lhs), RHS(rhs) {}
+
+ virtual ~SCEVUDivExpr();
+ public:
+ const SCEVHandle &getLHS() const { return LHS; }
+ const SCEVHandle &getRHS() const { return RHS; }
+
+ virtual bool isLoopInvariant(const Loop *L) const {
+ return LHS->isLoopInvariant(L) && RHS->isLoopInvariant(L);
+ }
+
+ virtual bool hasComputableLoopEvolution(const Loop *L) const {
+ return LHS->hasComputableLoopEvolution(L) &&
+ RHS->hasComputableLoopEvolution(L);
+ }
+
+ SCEVHandle replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym,
+ const SCEVHandle &Conc,
+ ScalarEvolution &SE) const {
+ SCEVHandle L = LHS->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
+ SCEVHandle R = RHS->replaceSymbolicValuesWithConcrete(Sym, Conc, SE);
+ if (L == LHS && R == RHS)
+ return this;
+ else
+ return SE.getUDivExpr(L, R);
+ }
+
+
+ virtual const Type *getType() const;
+
+ void print(std::ostream &OS) const;
+ void print(std::ostream *OS) const { if (OS) print(*OS); }
+
+ /// Methods for support type inquiry through isa, cast, and dyn_cast:
+ static inline bool classof(const SCEVUDivExpr *S) { return true; }
+ static inline bool classof(const SCEV *S) {
+ return S->getSCEVType() == scUDivExpr;
+ }
+ };
+
+
+ //===--------------------------------------------------------------------===//
/// SCEVAddRecExpr - This node represents a polynomial recurrence on the trip
/// count of the specified loop.
///
@@ -519,6 +568,8 @@
return ((SC*)this)->visitMulExpr((SCEVMulExpr*)S);
case scSDivExpr:
return ((SC*)this)->visitSDivExpr((SCEVSDivExpr*)S);
+ case scUDivExpr:
+ return ((SC*)this)->visitUDivExpr((SCEVUDivExpr*)S);
case scAddRecExpr:
return ((SC*)this)->visitAddRecExpr((SCEVAddRecExpr*)S);
case scUnknown:
Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=44163&r1=44162&r2=44163&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Thu Nov 15 00:30:50 2007
@@ -344,6 +344,24 @@
return LHS->getType();
}
+// SCEVUDivs - Only allow the creation of one SCEVUDivExpr for any particular
+// input. Don't use a SCEVHandle here, or else the object will never be
+// deleted!
+static ManagedStatic<std::map<std::pair<SCEV*, SCEV*>,
+ SCEVUDivExpr*> > SCEVUDivs;
+
+SCEVUDivExpr::~SCEVUDivExpr() {
+ SCEVUDivs->erase(std::make_pair(LHS, RHS));
+}
+
+void SCEVUDivExpr::print(std::ostream &OS) const {
+ OS << "(" << *LHS << " /u " << *RHS << ")";
+}
+
+const Type *SCEVUDivExpr::getType() const {
+ return LHS->getType();
+}
+
// SCEVAddRecExprs - Only allow the creation of one SCEVAddRecExpr for any
// particular input. Don't use a SCEVHandle here, or else the object will never
// be deleted!
@@ -573,7 +591,7 @@
for (unsigned i = 1, e = getNumOperands(); i != e; ++i) {
SCEVHandle BC = PartialFact(It, i, SE);
Divisor *= i;
- SCEVHandle Val = SE.getSDivExpr(SE.getMulExpr(BC, getOperand(i)),
+ SCEVHandle Val = SE.getUDivExpr(SE.getMulExpr(BC, getOperand(i)),
SE.getIntegerSCEV(Divisor,Ty));
Result = SE.getAddExpr(Result, Val);
}
@@ -1037,7 +1055,8 @@
return Result;
}
-SCEVHandle ScalarEvolution::getSDivExpr(const SCEVHandle &LHS, const SCEVHandle &RHS) {
+SCEVHandle ScalarEvolution::getSDivExpr(const SCEVHandle &LHS,
+ const SCEVHandle &RHS) {
if (SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) {
if (RHSC->getValue()->equalsInt(1))
return LHS; // X sdiv 1 --> x
@@ -1058,6 +1077,26 @@
return Result;
}
+SCEVHandle ScalarEvolution::getUDivExpr(const SCEVHandle &LHS,
+ const SCEVHandle &RHS) {
+ if (SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) {
+ if (RHSC->getValue()->equalsInt(1))
+ return LHS; // X udiv 1 --> x
+
+ if (SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS)) {
+ Constant *LHSCV = LHSC->getValue();
+ Constant *RHSCV = RHSC->getValue();
+ return getUnknown(ConstantExpr::getUDiv(LHSCV, RHSCV));
+ }
+ }
+
+ // FIXME: implement folding of (X*4)/4 when we know X*4 doesn't overflow.
+
+ SCEVUDivExpr *&Result = (*SCEVUDivs)[std::make_pair(LHS, RHS)];
+ if (Result == 0) Result = new SCEVUDivExpr(LHS, RHS);
+ return Result;
+}
+
/// SCEVAddRecExpr::get - Get a add recurrence expression for the
/// specified loop. Simplify the expression as much as possible.
@@ -1484,8 +1523,6 @@
case Instruction::SDiv:
return SE.getSDivExpr(getSCEV(I->getOperand(0)),
getSCEV(I->getOperand(1)));
- break;
-
case Instruction::Sub:
return SE.getMinusSCEV(getSCEV(I->getOperand(0)),
getSCEV(I->getOperand(1)));
@@ -2145,6 +2182,16 @@
return SE.getSDivExpr(LHS, RHS);
}
+ if (SCEVUDivExpr *Div = dyn_cast<SCEVUDivExpr>(V)) {
+ SCEVHandle LHS = getSCEVAtScope(Div->getLHS(), L);
+ if (LHS == UnknownValue) return LHS;
+ SCEVHandle RHS = getSCEVAtScope(Div->getRHS(), L);
+ if (RHS == UnknownValue) return RHS;
+ if (LHS == Div->getLHS() && RHS == Div->getRHS())
+ return Div; // must be loop invariant
+ return SE.getUDivExpr(LHS, RHS);
+ }
+
// If this is a loop recurrence for a loop that does not contain L, then we
// are dealing with the final value computed by the loop.
if (SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(V)) {
Added: llvm/trunk/test/Analysis/ScalarEvolution/2007-11-14-SignedAddRec.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/2007-11-14-SignedAddRec.ll?rev=44163&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/2007-11-14-SignedAddRec.ll (added)
+++ llvm/trunk/test/Analysis/ScalarEvolution/2007-11-14-SignedAddRec.ll Thu Nov 15 00:30:50 2007
@@ -0,0 +1,24 @@
+; RUN: llvm-as < %s | opt -indvars | llvm-dis | grep printd | grep 1206807378
+; PR1798
+
+declare void @printd(i32)
+
+define i32 @test() {
+entry:
+ br label %bb6
+
+bb: ; preds = %bb6
+ %tmp3 = add i32 %x.0, %i.0 ; <i32> [#uses=1]
+ %tmp5 = add i32 %i.0, 1 ; <i32> [#uses=1]
+ br label %bb6
+
+bb6: ; preds = %bb, %entry
+ %i.0 = phi i32 [ 0, %entry ], [ %tmp5, %bb ] ; <i32> [#uses=3]
+ %x.0 = phi i32 [ 0, %entry ], [ %tmp3, %bb ] ; <i32> [#uses=3]
+ %tmp8 = icmp slt i32 %i.0, 123456789 ; <i1> [#uses=1]
+ br i1 %tmp8, label %bb, label %bb10
+
+bb10: ; preds = %bb6
+ call void @printd(i32 %x.0)
+ ret i32 0
+}
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