[polly] r312410 - [ScopDetect/Info] Look through PHIs that follow an error block
Tobias Grosser via llvm-commits
llvm-commits at lists.llvm.org
Sat Sep 2 01:25:55 PDT 2017
Author: grosser
Date: Sat Sep 2 01:25:55 2017
New Revision: 312410
URL: http://llvm.org/viewvc/llvm-project?rev=312410&view=rev
Log:
[ScopDetect/Info] Look through PHIs that follow an error block
In case a PHI node follows an error block we can assume that the incoming value
can only come from the node that is not an error block. As a result, conditions
that seemed non-affine before are now in fact affine.
Added:
polly/trunk/test/ScopInfo/phi_after_error_block.ll
Modified:
polly/trunk/include/polly/ScopInfo.h
polly/trunk/include/polly/Support/SCEVValidator.h
polly/trunk/lib/Analysis/ScopBuilder.cpp
polly/trunk/lib/Analysis/ScopDetection.cpp
polly/trunk/lib/Analysis/ScopInfo.cpp
polly/trunk/lib/Support/SCEVValidator.cpp
Modified: polly/trunk/include/polly/ScopInfo.h
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/include/polly/ScopInfo.h?rev=312410&r1=312409&r2=312410&view=diff
==============================================================================
--- polly/trunk/include/polly/ScopInfo.h (original)
+++ polly/trunk/include/polly/ScopInfo.h Sat Sep 2 01:25:55 2017
@@ -1699,6 +1699,7 @@ private:
friend class ScopBuilder;
ScalarEvolution *SE;
+ DominatorTree *DT;
/// The underlying Region.
Region &R;
@@ -1927,12 +1928,9 @@ private:
static int getNextID(std::string ParentFunc);
/// Scop constructor; invoked from ScopBuilder::buildScop.
- Scop(Region &R, ScalarEvolution &SE, LoopInfo &LI,
+ Scop(Region &R, ScalarEvolution &SE, LoopInfo &LI, DominatorTree &DT,
ScopDetection::DetectionContext &DC, OptimizationRemarkEmitter &ORE);
- /// Return the LoopInfo used for this Scop.
- LoopInfo *getLI() const { return Affinator.getLI(); }
-
//@}
/// Initialize this ScopBuilder.
@@ -2402,8 +2400,15 @@ public:
/// Remove the metadata stored for @p Access.
void removeAccessData(MemoryAccess *Access);
+ /// Return the scalar evolution.
ScalarEvolution *getSE() const;
+ /// Return the dominator tree.
+ DominatorTree *getDT() const { return DT; }
+
+ /// Return the LoopInfo used for this Scop.
+ LoopInfo *getLI() const { return Affinator.getLI(); }
+
/// Get the count of parameters used in this Scop.
///
/// @return The count of parameters used in this Scop.
Modified: polly/trunk/include/polly/Support/SCEVValidator.h
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/include/polly/Support/SCEVValidator.h?rev=312410&r1=312409&r2=312410&view=diff
==============================================================================
--- polly/trunk/include/polly/Support/SCEVValidator.h (original)
+++ polly/trunk/include/polly/Support/SCEVValidator.h Sat Sep 2 01:25:55 2017
@@ -94,6 +94,17 @@ ParameterSetTy getParamsInAffineExpr(con
/// @returns The constant factor in @p M and the rest of @p M.
std::pair<const llvm::SCEVConstant *, const llvm::SCEV *>
extractConstantFactor(const llvm::SCEV *M, llvm::ScalarEvolution &SE);
+
+/// Try to look through PHI nodes, where some incoming edges come from error
+/// blocks.
+///
+/// In case a PHI node follows an error block we can assume that the incoming
+/// value can only come from the node that is not an error block. As a result,
+/// conditions that seemed non-affine before are now in fact affine.
+const llvm::SCEV *tryForwardThroughPHI(const llvm::SCEV *Expr, llvm::Region &R,
+ llvm::ScalarEvolution &SE,
+ llvm::LoopInfo &LI,
+ const llvm::DominatorTree &DT);
} // namespace polly
#endif
Modified: polly/trunk/lib/Analysis/ScopBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Analysis/ScopBuilder.cpp?rev=312410&r1=312409&r2=312410&view=diff
==============================================================================
--- polly/trunk/lib/Analysis/ScopBuilder.cpp (original)
+++ polly/trunk/lib/Analysis/ScopBuilder.cpp Sat Sep 2 01:25:55 2017
@@ -1181,7 +1181,7 @@ static inline BasicBlock *getRegionNodeB
void ScopBuilder::buildScop(Region &R, AssumptionCache &AC,
OptimizationRemarkEmitter &ORE) {
- scop.reset(new Scop(R, SE, LI, *SD.getDetectionContext(&R), ORE));
+ scop.reset(new Scop(R, SE, LI, DT, *SD.getDetectionContext(&R), ORE));
buildStmts(R);
buildAccessFunctions();
Modified: polly/trunk/lib/Analysis/ScopDetection.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Analysis/ScopDetection.cpp?rev=312410&r1=312409&r2=312410&view=diff
==============================================================================
--- polly/trunk/lib/Analysis/ScopDetection.cpp (original)
+++ polly/trunk/lib/Analysis/ScopDetection.cpp Sat Sep 2 01:25:55 2017
@@ -607,6 +607,9 @@ bool ScopDetection::isValidBranch(BasicB
const SCEV *LHS = SE.getSCEVAtScope(ICmp->getOperand(0), L);
const SCEV *RHS = SE.getSCEVAtScope(ICmp->getOperand(1), L);
+ LHS = tryForwardThroughPHI(LHS, Context.CurRegion, SE, LI, DT);
+ RHS = tryForwardThroughPHI(RHS, Context.CurRegion, SE, LI, DT);
+
// If unsigned operations are not allowed try to approximate the region.
if (ICmp->isUnsigned() && !PollyAllowUnsignedOperations)
return !IsLoopBranch && AllowNonAffineSubRegions &&
Modified: polly/trunk/lib/Analysis/ScopInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Analysis/ScopInfo.cpp?rev=312410&r1=312409&r2=312410&view=diff
==============================================================================
--- polly/trunk/lib/Analysis/ScopInfo.cpp (original)
+++ polly/trunk/lib/Analysis/ScopInfo.cpp Sat Sep 2 01:25:55 2017
@@ -1451,11 +1451,10 @@ getPwAff(Scop &S, BasicBlock *BB,
/// This will fill @p ConditionSets with the conditions under which control
/// will be moved from @p SI to its successors. Hence, @p ConditionSets will
/// have as many elements as @p SI has successors.
-static bool
-buildConditionSets(Scop &S, BasicBlock *BB, SwitchInst *SI, Loop *L,
- __isl_keep isl_set *Domain,
- DenseMap<BasicBlock *, isl::set> &InvalidDomainMap,
- SmallVectorImpl<__isl_give isl_set *> &ConditionSets) {
+bool buildConditionSets(Scop &S, BasicBlock *BB, SwitchInst *SI, Loop *L,
+ __isl_keep isl_set *Domain,
+ DenseMap<BasicBlock *, isl::set> &InvalidDomainMap,
+ SmallVectorImpl<__isl_give isl_set *> &ConditionSets) {
Value *Condition = getConditionFromTerminator(SI);
assert(Condition && "No condition for switch");
@@ -1497,7 +1496,7 @@ buildConditionSets(Scop &S, BasicBlock *
/// @param IsStrictUpperBound holds information on the predicate relation
/// between TestVal and UpperBound, i.e,
/// TestVal < UpperBound OR TestVal <= UpperBound
-static __isl_give isl_set *
+__isl_give isl_set *
buildUnsignedConditionSets(Scop &S, BasicBlock *BB, Value *Condition,
__isl_keep isl_set *Domain, const SCEV *SCEV_TestVal,
const SCEV *SCEV_UpperBound,
@@ -1537,11 +1536,10 @@ buildUnsignedConditionSets(Scop &S, Basi
/// have as many elements as @p TI has successors. If @p TI is nullptr the
/// context under which @p Condition is true/false will be returned as the
/// new elements of @p ConditionSets.
-static bool
-buildConditionSets(Scop &S, BasicBlock *BB, Value *Condition,
- TerminatorInst *TI, Loop *L, __isl_keep isl_set *Domain,
- DenseMap<BasicBlock *, isl::set> &InvalidDomainMap,
- SmallVectorImpl<__isl_give isl_set *> &ConditionSets) {
+bool buildConditionSets(Scop &S, BasicBlock *BB, Value *Condition,
+ TerminatorInst *TI, Loop *L, __isl_keep isl_set *Domain,
+ DenseMap<BasicBlock *, isl::set> &InvalidDomainMap,
+ SmallVectorImpl<__isl_give isl_set *> &ConditionSets) {
isl_set *ConsequenceCondSet = nullptr;
if (auto *CCond = dyn_cast<ConstantInt>(Condition)) {
if (CCond->isZero())
@@ -1577,6 +1575,10 @@ buildConditionSets(Scop &S, BasicBlock *
"Condition of exiting branch was neither constant nor ICmp!");
ScalarEvolution &SE = *S.getSE();
+ LoopInfo &LI = *S.getLI();
+ DominatorTree &DT = *S.getDT();
+ Region &R = S.getRegion();
+
isl_pw_aff *LHS, *RHS;
// For unsigned comparisons we assumed the signed bit of neither operand
// to be set. The comparison is equal to a signed comparison under this
@@ -1585,6 +1587,9 @@ buildConditionSets(Scop &S, BasicBlock *
const SCEV *LeftOperand = SE.getSCEVAtScope(ICond->getOperand(0), L),
*RightOperand = SE.getSCEVAtScope(ICond->getOperand(1), L);
+ LeftOperand = tryForwardThroughPHI(LeftOperand, R, SE, LI, DT);
+ RightOperand = tryForwardThroughPHI(RightOperand, R, SE, LI, DT);
+
switch (ICond->getPredicate()) {
case ICmpInst::ICMP_ULT:
ConsequenceCondSet =
@@ -1653,11 +1658,10 @@ buildConditionSets(Scop &S, BasicBlock *
/// This will fill @p ConditionSets with the conditions under which control
/// will be moved from @p TI to its successors. Hence, @p ConditionSets will
/// have as many elements as @p TI has successors.
-static bool
-buildConditionSets(Scop &S, BasicBlock *BB, TerminatorInst *TI, Loop *L,
- __isl_keep isl_set *Domain,
- DenseMap<BasicBlock *, isl::set> &InvalidDomainMap,
- SmallVectorImpl<__isl_give isl_set *> &ConditionSets) {
+bool buildConditionSets(Scop &S, BasicBlock *BB, TerminatorInst *TI, Loop *L,
+ __isl_keep isl_set *Domain,
+ DenseMap<BasicBlock *, isl::set> &InvalidDomainMap,
+ SmallVectorImpl<__isl_give isl_set *> &ConditionSets) {
if (SwitchInst *SI = dyn_cast<SwitchInst>(TI))
return buildConditionSets(S, BB, SI, L, Domain, InvalidDomainMap,
ConditionSets);
@@ -3357,8 +3361,9 @@ int Scop::getNextID(std::string ParentFu
}
Scop::Scop(Region &R, ScalarEvolution &ScalarEvolution, LoopInfo &LI,
- ScopDetection::DetectionContext &DC, OptimizationRemarkEmitter &ORE)
- : SE(&ScalarEvolution), R(R), name(R.getNameStr()),
+ DominatorTree &DT, ScopDetection::DetectionContext &DC,
+ OptimizationRemarkEmitter &ORE)
+ : SE(&ScalarEvolution), DT(&DT), R(R), name(R.getNameStr()),
HasSingleExitEdge(R.getExitingBlock()), DC(DC), ORE(ORE),
IslCtx(isl_ctx_alloc(), isl_ctx_free), Affinator(this, LI),
ID(getNextID((*R.getEntry()->getParent()).getName().str())) {
Modified: polly/trunk/lib/Support/SCEVValidator.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Support/SCEVValidator.cpp?rev=312410&r1=312409&r2=312410&view=diff
==============================================================================
--- polly/trunk/lib/Support/SCEVValidator.cpp (original)
+++ polly/trunk/lib/Support/SCEVValidator.cpp Sat Sep 2 01:25:55 2017
@@ -735,4 +735,30 @@ extractConstantFactor(const SCEV *S, Sca
return std::make_pair(ConstPart, SE.getMulExpr(LeftOvers));
}
+
+const SCEV *tryForwardThroughPHI(const SCEV *Expr, Region &R,
+ ScalarEvolution &SE, LoopInfo &LI,
+ const DominatorTree &DT) {
+ if (auto *Unknown = dyn_cast<SCEVUnknown>(Expr)) {
+ Value *V = Unknown->getValue();
+ auto *PHI = dyn_cast<PHINode>(V);
+ if (!PHI)
+ return Expr;
+
+ Value *Final = nullptr;
+
+ for (unsigned i = 0; i < PHI->getNumIncomingValues(); i++) {
+ if (isErrorBlock(*PHI->getIncomingBlock(i), R, LI, DT))
+ continue;
+ if (Final)
+ return Expr;
+ Final = PHI->getIncomingValue(i);
+ }
+
+ if (Final)
+ return SE.getSCEV(Final);
+ }
+ return Expr;
+}
+
} // namespace polly
Added: polly/trunk/test/ScopInfo/phi_after_error_block.ll
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/test/ScopInfo/phi_after_error_block.ll?rev=312410&view=auto
==============================================================================
--- polly/trunk/test/ScopInfo/phi_after_error_block.ll (added)
+++ polly/trunk/test/ScopInfo/phi_after_error_block.ll Sat Sep 2 01:25:55 2017
@@ -0,0 +1,61 @@
+; RUN: opt %loadPolly -polly-scops -analyze < %s | FileCheck %s
+
+declare void @bar()
+
+define void @foo(float* %A, i64 %p) {
+start:
+ br label %next
+
+next:
+ %cmpA = icmp sle i64 %p, 0
+ br i1 %cmpA, label %error, label %ok
+
+error:
+ call void @bar()
+ br label %merge
+
+ok:
+ br label %merge
+
+merge:
+ %phi = phi i64 [0, %error], [1, %ok]
+ store float 42.0, float* %A
+ %cmp = icmp eq i64 %phi, %p
+ br i1 %cmp, label %loop, label %exit
+
+loop:
+ %indvar = phi i64 [0, %merge], [%indvar.next, %loop]
+ store float 42.0, float* %A
+ %indvar.next = add i64 %indvar, 1
+ %cmp2 = icmp sle i64 %indvar, 1024
+ br i1 %cmp2, label %loop, label %exit
+
+exit:
+ ret void
+}
+
+; CHECK: Statements {
+; CHECK-NEXT: Stmt_ok
+; CHECK-NEXT: Domain :=
+; CHECK-NEXT: [p] -> { Stmt_ok[] : p > 0 };
+; CHECK-NEXT: Schedule :=
+; CHECK-NEXT: [p] -> { Stmt_ok[] -> [0, 0] };
+; CHECK-NEXT: MustWriteAccess := [Reduction Type: NONE] [Scalar: 1]
+; CHECK-NEXT: [p] -> { Stmt_ok[] -> MemRef_phi__phi[] };
+; CHECK-NEXT: Stmt_merge
+; CHECK-NEXT: Domain :=
+; CHECK-NEXT: [p] -> { Stmt_merge[] };
+; CHECK-NEXT: Schedule :=
+; CHECK-NEXT: [p] -> { Stmt_merge[] -> [1, 0] };
+; CHECK-NEXT: ReadAccess := [Reduction Type: NONE] [Scalar: 1]
+; CHECK-NEXT: [p] -> { Stmt_merge[] -> MemRef_phi__phi[] };
+; CHECK-NEXT: MustWriteAccess := [Reduction Type: NONE] [Scalar: 0]
+; CHECK-NEXT: [p] -> { Stmt_merge[] -> MemRef_A[0] };
+; CHECK-NEXT: Stmt_loop
+; CHECK-NEXT: Domain :=
+; CHECK-NEXT: [p] -> { Stmt_loop[i0] : p = 1 and 0 <= i0 <= 1025 };
+; CHECK-NEXT: Schedule :=
+; CHECK-NEXT: [p] -> { Stmt_loop[i0] -> [2, i0] };
+; CHECK-NEXT: MustWriteAccess := [Reduction Type: NONE] [Scalar: 0]
+; CHECK-NEXT: [p] -> { Stmt_loop[i0] -> MemRef_A[0] };
+; CHECK-NEXT: }
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