[llvm] r217345 - Make use of @llvm.assume from LazyValueInfo
Hal Finkel
hfinkel at anl.gov
Sun Sep 7 13:29:59 PDT 2014
Author: hfinkel
Date: Sun Sep 7 15:29:59 2014
New Revision: 217345
URL: http://llvm.org/viewvc/llvm-project?rev=217345&view=rev
Log:
Make use of @llvm.assume from LazyValueInfo
This change teaches LazyValueInfo to use the @llvm.assume intrinsic. Like with
the known-bits change (r217342), this requires feeding a "context" instruction
pointer through many functions. Aside from a little refactoring to reuse the
logic that turns predicates into constant ranges in LVI, the only new code is
that which can 'merge' the range from an assumption into that otherwise
computed. There is also a small addition to JumpThreading so that it can have
LVI use assumptions in the same block as the comparison feeding a conditional
branch.
With this patch, we can now simplify this as expected:
int foo(int a) {
__builtin_assume(a > 5);
if (a > 3) {
bar();
return 1;
}
return 0;
}
Added:
llvm/trunk/test/Transforms/JumpThreading/assume.ll
Modified:
llvm/trunk/include/llvm/Analysis/LazyValueInfo.h
llvm/trunk/lib/Analysis/LazyValueInfo.cpp
llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp
Modified: llvm/trunk/include/llvm/Analysis/LazyValueInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/LazyValueInfo.h?rev=217345&r1=217344&r2=217345&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/LazyValueInfo.h (original)
+++ llvm/trunk/include/llvm/Analysis/LazyValueInfo.h Sun Sep 7 15:29:59 2014
@@ -18,16 +18,21 @@
#include "llvm/Pass.h"
namespace llvm {
+ class AssumptionTracker;
class Constant;
class DataLayout;
+ class DominatorTree;
+ class Instruction;
class TargetLibraryInfo;
class Value;
/// LazyValueInfo - This pass computes, caches, and vends lazy value constraint
/// information.
class LazyValueInfo : public FunctionPass {
+ AssumptionTracker *AT;
const DataLayout *DL;
class TargetLibraryInfo *TLI;
+ DominatorTree *DT;
void *PImpl;
LazyValueInfo(const LazyValueInfo&) LLVM_DELETED_FUNCTION;
void operator=(const LazyValueInfo&) LLVM_DELETED_FUNCTION;
@@ -50,16 +55,23 @@ public:
/// with a constant is known to be true or false on the specified CFG edge.
/// Pred is a CmpInst predicate.
Tristate getPredicateOnEdge(unsigned Pred, Value *V, Constant *C,
- BasicBlock *FromBB, BasicBlock *ToBB);
-
+ BasicBlock *FromBB, BasicBlock *ToBB,
+ Instruction *CxtI = nullptr);
+ /// getPredicateAt - Determine whether the specified value comparison
+ /// with a constant is known to be true or false at the specified instruction
+ /// (from an assume intrinsic). Pred is a CmpInst predicate.
+ Tristate getPredicateAt(unsigned Pred, Value *V, Constant *C,
+ Instruction *CxtI);
+
/// getConstant - Determine whether the specified value is known to be a
/// constant at the end of the specified block. Return null if not.
- Constant *getConstant(Value *V, BasicBlock *BB);
+ Constant *getConstant(Value *V, BasicBlock *BB, Instruction *CxtI = nullptr);
/// getConstantOnEdge - Determine whether the specified value is known to be a
/// constant on the specified edge. Return null if not.
- Constant *getConstantOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB);
+ Constant *getConstantOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB,
+ Instruction *CxtI = nullptr);
/// threadEdge - Inform the analysis cache that we have threaded an edge from
/// PredBB to OldSucc to be from PredBB to NewSucc instead.
Modified: llvm/trunk/lib/Analysis/LazyValueInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/LazyValueInfo.cpp?rev=217345&r1=217344&r2=217345&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/LazyValueInfo.cpp (original)
+++ llvm/trunk/lib/Analysis/LazyValueInfo.cpp Sun Sep 7 15:29:59 2014
@@ -15,12 +15,14 @@
#include "llvm/Analysis/LazyValueInfo.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/STLExtras.h"
+#include "llvm/Analysis/AssumptionTracker.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Dominators.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/PatternMatch.h"
@@ -38,6 +40,7 @@ using namespace PatternMatch;
char LazyValueInfo::ID = 0;
INITIALIZE_PASS_BEGIN(LazyValueInfo, "lazy-value-info",
"Lazy Value Information Analysis", false, true)
+INITIALIZE_PASS_DEPENDENCY(AssumptionTracker)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
INITIALIZE_PASS_END(LazyValueInfo, "lazy-value-info",
"Lazy Value Information Analysis", false, true)
@@ -338,6 +341,13 @@ namespace {
/// during a query. It basically emulates the callstack of the naive
/// recursive value lookup process.
std::stack<std::pair<BasicBlock*, Value*> > BlockValueStack;
+
+ /// A pointer to the cache of @llvm.assume calls.
+ AssumptionTracker *AT;
+ /// An optional DL pointer.
+ const DataLayout *DL;
+ /// An optional DT pointer.
+ DominatorTree *DT;
friend struct LVIValueHandle;
@@ -364,7 +374,8 @@ namespace {
LVILatticeVal getBlockValue(Value *Val, BasicBlock *BB);
bool getEdgeValue(Value *V, BasicBlock *F, BasicBlock *T,
- LVILatticeVal &Result);
+ LVILatticeVal &Result,
+ Instruction *CxtI = nullptr);
bool hasBlockValue(Value *Val, BasicBlock *BB);
// These methods process one work item and may add more. A false value
@@ -377,6 +388,8 @@ namespace {
PHINode *PN, BasicBlock *BB);
bool solveBlockValueConstantRange(LVILatticeVal &BBLV,
Instruction *BBI, BasicBlock *BB);
+ void mergeAssumeBlockValueConstantRange(Value *Val, LVILatticeVal &BBLV,
+ Instruction *BBI);
void solve();
@@ -387,11 +400,18 @@ namespace {
public:
/// getValueInBlock - This is the query interface to determine the lattice
/// value for the specified Value* at the end of the specified block.
- LVILatticeVal getValueInBlock(Value *V, BasicBlock *BB);
+ LVILatticeVal getValueInBlock(Value *V, BasicBlock *BB,
+ Instruction *CxtI = nullptr);
+
+ /// getValueAt - This is the query interface to determine the lattice
+ /// value for the specified Value* at the specified instruction (generally
+ /// from an assume intrinsic).
+ LVILatticeVal getValueAt(Value *V, Instruction *CxtI);
/// getValueOnEdge - This is the query interface to determine the lattice
/// value for the specified Value* that is true on the specified edge.
- LVILatticeVal getValueOnEdge(Value *V, BasicBlock *FromBB,BasicBlock *ToBB);
+ LVILatticeVal getValueOnEdge(Value *V, BasicBlock *FromBB,BasicBlock *ToBB,
+ Instruction *CxtI = nullptr);
/// threadEdge - This is the update interface to inform the cache that an
/// edge from PredBB to OldSucc has been threaded to be from PredBB to
@@ -408,6 +428,10 @@ namespace {
ValueCache.clear();
OverDefinedCache.clear();
}
+
+ LazyValueInfoCache(AssumptionTracker *AT,
+ const DataLayout *DL = nullptr,
+ DominatorTree *DT = nullptr) : AT(AT), DL(DL), DT(DT) {}
};
} // end anonymous namespace
@@ -684,7 +708,7 @@ bool LazyValueInfoCache::solveBlockValue
BasicBlock *PhiBB = PN->getIncomingBlock(i);
Value *PhiVal = PN->getIncomingValue(i);
LVILatticeVal EdgeResult;
- EdgesMissing |= !getEdgeValue(PhiVal, PhiBB, BB, EdgeResult);
+ EdgesMissing |= !getEdgeValue(PhiVal, PhiBB, BB, EdgeResult, PN);
if (EdgesMissing)
continue;
@@ -709,6 +733,36 @@ bool LazyValueInfoCache::solveBlockValue
return true;
}
+static bool getValueFromFromCondition(Value *Val, ICmpInst *ICI,
+ LVILatticeVal &Result,
+ bool isTrueDest = true);
+
+// If we can determine a constant range for the value Val at the context
+// provided by the instruction BBI, then merge it into BBLV. If we did find a
+// constant range, return true.
+void LazyValueInfoCache::mergeAssumeBlockValueConstantRange(
+ Value *Val, LVILatticeVal &BBLV, Instruction *BBI) {
+ BBI = BBI ? BBI : dyn_cast<Instruction>(Val);
+ if (!BBI)
+ return;
+
+ for (auto &I : AT->assumptions(BBI->getParent()->getParent())) {
+ if (!isValidAssumeForContext(I, BBI, DL, DT))
+ continue;
+
+ Value *C = I->getArgOperand(0);
+ if (ICmpInst *ICI = dyn_cast<ICmpInst>(C)) {
+ LVILatticeVal Result;
+ if (getValueFromFromCondition(Val, ICI, Result)) {
+ if (BBLV.isOverdefined())
+ BBLV = Result;
+ else
+ BBLV.mergeIn(Result);
+ }
+ }
+ }
+}
+
bool LazyValueInfoCache::solveBlockValueConstantRange(LVILatticeVal &BBLV,
Instruction *BBI,
BasicBlock *BB) {
@@ -719,6 +773,7 @@ bool LazyValueInfoCache::solveBlockValue
}
LVILatticeVal LHSVal = getBlockValue(BBI->getOperand(0), BB);
+ mergeAssumeBlockValueConstantRange(BBI->getOperand(0), LHSVal, BBI);
if (!LHSVal.isConstantRange()) {
BBLV.markOverdefined();
return true;
@@ -790,6 +845,47 @@ bool LazyValueInfoCache::solveBlockValue
return true;
}
+bool getValueFromFromCondition(Value *Val, ICmpInst *ICI,
+ LVILatticeVal &Result, bool isTrueDest) {
+ if (ICI && isa<Constant>(ICI->getOperand(1))) {
+ if (ICI->isEquality() && ICI->getOperand(0) == Val) {
+ // We know that V has the RHS constant if this is a true SETEQ or
+ // false SETNE.
+ if (isTrueDest == (ICI->getPredicate() == ICmpInst::ICMP_EQ))
+ Result = LVILatticeVal::get(cast<Constant>(ICI->getOperand(1)));
+ else
+ Result = LVILatticeVal::getNot(cast<Constant>(ICI->getOperand(1)));
+ return true;
+ }
+
+ // Recognize the range checking idiom that InstCombine produces.
+ // (X-C1) u< C2 --> [C1, C1+C2)
+ ConstantInt *NegOffset = nullptr;
+ if (ICI->getPredicate() == ICmpInst::ICMP_ULT)
+ match(ICI->getOperand(0), m_Add(m_Specific(Val),
+ m_ConstantInt(NegOffset)));
+
+ ConstantInt *CI = dyn_cast<ConstantInt>(ICI->getOperand(1));
+ if (CI && (ICI->getOperand(0) == Val || NegOffset)) {
+ // Calculate the range of values that would satisfy the comparison.
+ ConstantRange CmpRange(CI->getValue());
+ ConstantRange TrueValues =
+ ConstantRange::makeICmpRegion(ICI->getPredicate(), CmpRange);
+
+ if (NegOffset) // Apply the offset from above.
+ TrueValues = TrueValues.subtract(NegOffset->getValue());
+
+ // If we're interested in the false dest, invert the condition.
+ if (!isTrueDest) TrueValues = TrueValues.inverse();
+
+ Result = LVILatticeVal::getRange(TrueValues);
+ return true;
+ }
+ }
+
+ return false;
+}
+
/// \brief Compute the value of Val on the edge BBFrom -> BBTo. Returns false if
/// Val is not constrained on the edge.
static bool getEdgeValueLocal(Value *Val, BasicBlock *BBFrom,
@@ -816,41 +912,8 @@ static bool getEdgeValueLocal(Value *Val
// If the condition of the branch is an equality comparison, we may be
// able to infer the value.
ICmpInst *ICI = dyn_cast<ICmpInst>(BI->getCondition());
- if (ICI && isa<Constant>(ICI->getOperand(1))) {
- if (ICI->isEquality() && ICI->getOperand(0) == Val) {
- // We know that V has the RHS constant if this is a true SETEQ or
- // false SETNE.
- if (isTrueDest == (ICI->getPredicate() == ICmpInst::ICMP_EQ))
- Result = LVILatticeVal::get(cast<Constant>(ICI->getOperand(1)));
- else
- Result = LVILatticeVal::getNot(cast<Constant>(ICI->getOperand(1)));
- return true;
- }
-
- // Recognize the range checking idiom that InstCombine produces.
- // (X-C1) u< C2 --> [C1, C1+C2)
- ConstantInt *NegOffset = nullptr;
- if (ICI->getPredicate() == ICmpInst::ICMP_ULT)
- match(ICI->getOperand(0), m_Add(m_Specific(Val),
- m_ConstantInt(NegOffset)));
-
- ConstantInt *CI = dyn_cast<ConstantInt>(ICI->getOperand(1));
- if (CI && (ICI->getOperand(0) == Val || NegOffset)) {
- // Calculate the range of values that would satisfy the comparison.
- ConstantRange CmpRange(CI->getValue());
- ConstantRange TrueValues =
- ConstantRange::makeICmpRegion(ICI->getPredicate(), CmpRange);
-
- if (NegOffset) // Apply the offset from above.
- TrueValues = TrueValues.subtract(NegOffset->getValue());
-
- // If we're interested in the false dest, invert the condition.
- if (!isTrueDest) TrueValues = TrueValues.inverse();
-
- Result = LVILatticeVal::getRange(TrueValues);
- return true;
- }
- }
+ if (getValueFromFromCondition(Val, ICI, Result, isTrueDest))
+ return true;
}
}
@@ -884,7 +947,8 @@ static bool getEdgeValueLocal(Value *Val
/// \brief Compute the value of Val on the edge BBFrom -> BBTo, or the value at
/// the basic block if the edge does not constraint Val.
bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom,
- BasicBlock *BBTo, LVILatticeVal &Result) {
+ BasicBlock *BBTo, LVILatticeVal &Result,
+ Instruction *CxtI) {
// If already a constant, there is nothing to compute.
if (Constant *VC = dyn_cast<Constant>(Val)) {
Result = LVILatticeVal::get(VC);
@@ -906,6 +970,7 @@ bool LazyValueInfoCache::getEdgeValue(Va
// Try to intersect ranges of the BB and the constraint on the edge.
LVILatticeVal InBlock = getBlockValue(Val, BBFrom);
+ mergeAssumeBlockValueConstantRange(Val, InBlock, CxtI);
if (!InBlock.isConstantRange())
return true;
@@ -922,30 +987,45 @@ bool LazyValueInfoCache::getEdgeValue(Va
// if we couldn't compute the value on the edge, use the value from the BB
Result = getBlockValue(Val, BBFrom);
+ mergeAssumeBlockValueConstantRange(Val, Result, CxtI);
return true;
}
-LVILatticeVal LazyValueInfoCache::getValueInBlock(Value *V, BasicBlock *BB) {
+LVILatticeVal LazyValueInfoCache::getValueInBlock(Value *V, BasicBlock *BB,
+ Instruction *CxtI) {
DEBUG(dbgs() << "LVI Getting block end value " << *V << " at '"
<< BB->getName() << "'\n");
BlockValueStack.push(std::make_pair(BB, V));
solve();
LVILatticeVal Result = getBlockValue(V, BB);
+ mergeAssumeBlockValueConstantRange(V, Result, CxtI);
+
+ DEBUG(dbgs() << " Result = " << Result << "\n");
+ return Result;
+}
+
+LVILatticeVal LazyValueInfoCache::getValueAt(Value *V, Instruction *CxtI) {
+ DEBUG(dbgs() << "LVI Getting value " << *V << " at '"
+ << CxtI->getName() << "'\n");
+
+ LVILatticeVal Result;
+ mergeAssumeBlockValueConstantRange(V, Result, CxtI);
DEBUG(dbgs() << " Result = " << Result << "\n");
return Result;
}
LVILatticeVal LazyValueInfoCache::
-getValueOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB) {
+getValueOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB,
+ Instruction *CxtI) {
DEBUG(dbgs() << "LVI Getting edge value " << *V << " from '"
<< FromBB->getName() << "' to '" << ToBB->getName() << "'\n");
LVILatticeVal Result;
- if (!getEdgeValue(V, FromBB, ToBB, Result)) {
+ if (!getEdgeValue(V, FromBB, ToBB, Result, CxtI)) {
solve();
- bool WasFastQuery = getEdgeValue(V, FromBB, ToBB, Result);
+ bool WasFastQuery = getEdgeValue(V, FromBB, ToBB, Result, CxtI);
(void)WasFastQuery;
assert(WasFastQuery && "More work to do after problem solved?");
}
@@ -1019,39 +1099,51 @@ void LazyValueInfoCache::threadEdge(Basi
//===----------------------------------------------------------------------===//
/// getCache - This lazily constructs the LazyValueInfoCache.
-static LazyValueInfoCache &getCache(void *&PImpl) {
+static LazyValueInfoCache &getCache(void *&PImpl,
+ AssumptionTracker *AT,
+ const DataLayout *DL = nullptr,
+ DominatorTree *DT = nullptr) {
if (!PImpl)
- PImpl = new LazyValueInfoCache();
+ PImpl = new LazyValueInfoCache(AT, DL, DT);
return *static_cast<LazyValueInfoCache*>(PImpl);
}
bool LazyValueInfo::runOnFunction(Function &F) {
- if (PImpl)
- getCache(PImpl).clear();
+ AT = &getAnalysis<AssumptionTracker>();
+
+ DominatorTreeWrapperPass *DTWP =
+ getAnalysisIfAvailable<DominatorTreeWrapperPass>();
+ DT = DTWP ? &DTWP->getDomTree() : nullptr;
DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
DL = DLP ? &DLP->getDataLayout() : nullptr;
TLI = &getAnalysis<TargetLibraryInfo>();
+ if (PImpl)
+ getCache(PImpl, AT, DL, DT).clear();
+
// Fully lazy.
return false;
}
void LazyValueInfo::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
+ AU.addRequired<AssumptionTracker>();
AU.addRequired<TargetLibraryInfo>();
}
void LazyValueInfo::releaseMemory() {
// If the cache was allocated, free it.
if (PImpl) {
- delete &getCache(PImpl);
+ delete &getCache(PImpl, AT);
PImpl = nullptr;
}
}
-Constant *LazyValueInfo::getConstant(Value *V, BasicBlock *BB) {
- LVILatticeVal Result = getCache(PImpl).getValueInBlock(V, BB);
+Constant *LazyValueInfo::getConstant(Value *V, BasicBlock *BB,
+ Instruction *CxtI) {
+ LVILatticeVal Result =
+ getCache(PImpl, AT, DL, DT).getValueInBlock(V, BB, CxtI);
if (Result.isConstant())
return Result.getConstant();
@@ -1066,8 +1158,10 @@ Constant *LazyValueInfo::getConstant(Val
/// getConstantOnEdge - Determine whether the specified value is known to be a
/// constant on the specified edge. Return null if not.
Constant *LazyValueInfo::getConstantOnEdge(Value *V, BasicBlock *FromBB,
- BasicBlock *ToBB) {
- LVILatticeVal Result = getCache(PImpl).getValueOnEdge(V, FromBB, ToBB);
+ BasicBlock *ToBB,
+ Instruction *CxtI) {
+ LVILatticeVal Result =
+ getCache(PImpl, AT, DL, DT).getValueOnEdge(V, FromBB, ToBB, CxtI);
if (Result.isConstant())
return Result.getConstant();
@@ -1079,51 +1173,47 @@ Constant *LazyValueInfo::getConstantOnEd
return nullptr;
}
-/// getPredicateOnEdge - Determine whether the specified value comparison
-/// with a constant is known to be true or false on the specified CFG edge.
-/// Pred is a CmpInst predicate.
-LazyValueInfo::Tristate
-LazyValueInfo::getPredicateOnEdge(unsigned Pred, Value *V, Constant *C,
- BasicBlock *FromBB, BasicBlock *ToBB) {
- LVILatticeVal Result = getCache(PImpl).getValueOnEdge(V, FromBB, ToBB);
-
+static LazyValueInfo::Tristate
+getPredicateResult(unsigned Pred, Constant *C, LVILatticeVal &Result,
+ const DataLayout *DL, TargetLibraryInfo *TLI) {
+
// If we know the value is a constant, evaluate the conditional.
Constant *Res = nullptr;
if (Result.isConstant()) {
Res = ConstantFoldCompareInstOperands(Pred, Result.getConstant(), C, DL,
TLI);
if (ConstantInt *ResCI = dyn_cast<ConstantInt>(Res))
- return ResCI->isZero() ? False : True;
- return Unknown;
+ return ResCI->isZero() ? LazyValueInfo::False : LazyValueInfo::True;
+ return LazyValueInfo::Unknown;
}
if (Result.isConstantRange()) {
ConstantInt *CI = dyn_cast<ConstantInt>(C);
- if (!CI) return Unknown;
+ if (!CI) return LazyValueInfo::Unknown;
ConstantRange CR = Result.getConstantRange();
if (Pred == ICmpInst::ICMP_EQ) {
if (!CR.contains(CI->getValue()))
- return False;
+ return LazyValueInfo::False;
if (CR.isSingleElement() && CR.contains(CI->getValue()))
- return True;
+ return LazyValueInfo::True;
} else if (Pred == ICmpInst::ICMP_NE) {
if (!CR.contains(CI->getValue()))
- return True;
+ return LazyValueInfo::True;
if (CR.isSingleElement() && CR.contains(CI->getValue()))
- return False;
+ return LazyValueInfo::False;
}
// Handle more complex predicates.
ConstantRange TrueValues =
ICmpInst::makeConstantRange((ICmpInst::Predicate)Pred, CI->getValue());
if (TrueValues.contains(CR))
- return True;
+ return LazyValueInfo::True;
if (TrueValues.inverse().contains(CR))
- return False;
- return Unknown;
+ return LazyValueInfo::False;
+ return LazyValueInfo::Unknown;
}
if (Result.isNotConstant()) {
@@ -1135,26 +1225,48 @@ LazyValueInfo::getPredicateOnEdge(unsign
Result.getNotConstant(), C, DL,
TLI);
if (Res->isNullValue())
- return False;
+ return LazyValueInfo::False;
} else if (Pred == ICmpInst::ICMP_NE) {
// !C1 != C -> true iff C1 == C.
Res = ConstantFoldCompareInstOperands(ICmpInst::ICMP_NE,
Result.getNotConstant(), C, DL,
TLI);
if (Res->isNullValue())
- return True;
+ return LazyValueInfo::True;
}
- return Unknown;
+ return LazyValueInfo::Unknown;
}
- return Unknown;
+ return LazyValueInfo::Unknown;
+}
+
+/// getPredicateOnEdge - Determine whether the specified value comparison
+/// with a constant is known to be true or false on the specified CFG edge.
+/// Pred is a CmpInst predicate.
+LazyValueInfo::Tristate
+LazyValueInfo::getPredicateOnEdge(unsigned Pred, Value *V, Constant *C,
+ BasicBlock *FromBB, BasicBlock *ToBB,
+ Instruction *CxtI) {
+ LVILatticeVal Result =
+ getCache(PImpl, AT, DL, DT).getValueOnEdge(V, FromBB, ToBB, CxtI);
+
+ return getPredicateResult(Pred, C, Result, DL, TLI);
+}
+
+LazyValueInfo::Tristate
+LazyValueInfo::getPredicateAt(unsigned Pred, Value *V, Constant *C,
+ Instruction *CxtI) {
+ LVILatticeVal Result =
+ getCache(PImpl, AT, DL, DT).getValueAt(V, CxtI);
+
+ return getPredicateResult(Pred, C, Result, DL, TLI);
}
void LazyValueInfo::threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc,
BasicBlock *NewSucc) {
- if (PImpl) getCache(PImpl).threadEdge(PredBB, OldSucc, NewSucc);
+ if (PImpl) getCache(PImpl, AT, DL, DT).threadEdge(PredBB, OldSucc, NewSucc);
}
void LazyValueInfo::eraseBlock(BasicBlock *BB) {
- if (PImpl) getCache(PImpl).eraseBlock(BB);
+ if (PImpl) getCache(PImpl, AT, DL, DT).eraseBlock(BB);
}
Modified: llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp?rev=217345&r1=217344&r2=217345&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp Sun Sep 7 15:29:59 2014
@@ -73,7 +73,7 @@ bool CorrelatedValuePropagation::process
if (S->getType()->isVectorTy()) return false;
if (isa<Constant>(S->getOperand(0))) return false;
- Constant *C = LVI->getConstant(S->getOperand(0), S->getParent());
+ Constant *C = LVI->getConstant(S->getOperand(0), S->getParent(), S);
if (!C) return false;
ConstantInt *CI = dyn_cast<ConstantInt>(C);
@@ -100,7 +100,7 @@ bool CorrelatedValuePropagation::process
Value *Incoming = P->getIncomingValue(i);
if (isa<Constant>(Incoming)) continue;
- Value *V = LVI->getConstantOnEdge(Incoming, P->getIncomingBlock(i), BB);
+ Value *V = LVI->getConstantOnEdge(Incoming, P->getIncomingBlock(i), BB, P);
// Look if the incoming value is a select with a constant but LVI tells us
// that the incoming value can never be that constant. In that case replace
@@ -114,7 +114,7 @@ bool CorrelatedValuePropagation::process
if (!C) continue;
if (LVI->getPredicateOnEdge(ICmpInst::ICMP_EQ, SI, C,
- P->getIncomingBlock(i), BB) !=
+ P->getIncomingBlock(i), BB, P) !=
LazyValueInfo::False)
continue;
@@ -148,7 +148,7 @@ bool CorrelatedValuePropagation::process
if (isa<Constant>(Pointer)) return false;
- Constant *C = LVI->getConstant(Pointer, I->getParent());
+ Constant *C = LVI->getConstant(Pointer, I->getParent(), I);
if (!C) return false;
++NumMemAccess;
@@ -174,13 +174,15 @@ bool CorrelatedValuePropagation::process
if (PI == PE) return false;
LazyValueInfo::Tristate Result = LVI->getPredicateOnEdge(C->getPredicate(),
- C->getOperand(0), Op1, *PI, C->getParent());
+ C->getOperand(0), Op1, *PI,
+ C->getParent(), C);
if (Result == LazyValueInfo::Unknown) return false;
++PI;
while (PI != PE) {
LazyValueInfo::Tristate Res = LVI->getPredicateOnEdge(C->getPredicate(),
- C->getOperand(0), Op1, *PI, C->getParent());
+ C->getOperand(0), Op1, *PI,
+ C->getParent(), C);
if (Res != Result) return false;
++PI;
}
@@ -230,7 +232,8 @@ bool CorrelatedValuePropagation::process
for (pred_iterator PI = PB; PI != PE; ++PI) {
// Is the switch condition equal to the case value?
LazyValueInfo::Tristate Value = LVI->getPredicateOnEdge(CmpInst::ICMP_EQ,
- Cond, Case, *PI, BB);
+ Cond, Case, *PI,
+ BB, SI);
// Give up on this case if nothing is known.
if (Value == LazyValueInfo::Unknown) {
State = LazyValueInfo::Unknown;
Modified: llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp?rev=217345&r1=217344&r2=217345&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp Sun Sep 7 15:29:59 2014
@@ -124,9 +124,11 @@ namespace {
bool ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB,
PredValueInfo &Result,
- ConstantPreference Preference);
+ ConstantPreference Preference,
+ Instruction *CxtI = nullptr);
bool ProcessThreadableEdges(Value *Cond, BasicBlock *BB,
- ConstantPreference Preference);
+ ConstantPreference Preference,
+ Instruction *CxtI = nullptr);
bool ProcessBranchOnPHI(PHINode *PN);
bool ProcessBranchOnXOR(BinaryOperator *BO);
@@ -340,7 +342,8 @@ static Constant *getKnownConstant(Value
///
bool JumpThreading::
ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB, PredValueInfo &Result,
- ConstantPreference Preference) {
+ ConstantPreference Preference,
+ Instruction *CxtI) {
// This method walks up use-def chains recursively. Because of this, we could
// get into an infinite loop going around loops in the use-def chain. To
// prevent this, keep track of what (value, block) pairs we've already visited
@@ -382,7 +385,7 @@ ComputeValueKnownInPredecessors(Value *V
BasicBlock *P = *PI;
// If the value is known by LazyValueInfo to be a constant in a
// predecessor, use that information to try to thread this block.
- Constant *PredCst = LVI->getConstantOnEdge(V, P, BB);
+ Constant *PredCst = LVI->getConstantOnEdge(V, P, BB, CxtI);
if (Constant *KC = getKnownConstant(PredCst, Preference))
Result.push_back(std::make_pair(KC, P));
}
@@ -398,7 +401,8 @@ ComputeValueKnownInPredecessors(Value *V
Result.push_back(std::make_pair(KC, PN->getIncomingBlock(i)));
} else {
Constant *CI = LVI->getConstantOnEdge(InVal,
- PN->getIncomingBlock(i), BB);
+ PN->getIncomingBlock(i),
+ BB, CxtI);
if (Constant *KC = getKnownConstant(CI, Preference))
Result.push_back(std::make_pair(KC, PN->getIncomingBlock(i)));
}
@@ -417,9 +421,9 @@ ComputeValueKnownInPredecessors(Value *V
if (I->getOpcode() == Instruction::Or ||
I->getOpcode() == Instruction::And) {
ComputeValueKnownInPredecessors(I->getOperand(0), BB, LHSVals,
- WantInteger);
+ WantInteger, CxtI);
ComputeValueKnownInPredecessors(I->getOperand(1), BB, RHSVals,
- WantInteger);
+ WantInteger, CxtI);
if (LHSVals.empty() && RHSVals.empty())
return false;
@@ -460,7 +464,7 @@ ComputeValueKnownInPredecessors(Value *V
isa<ConstantInt>(I->getOperand(1)) &&
cast<ConstantInt>(I->getOperand(1))->isOne()) {
ComputeValueKnownInPredecessors(I->getOperand(0), BB, Result,
- WantInteger);
+ WantInteger, CxtI);
if (Result.empty())
return false;
@@ -478,7 +482,7 @@ ComputeValueKnownInPredecessors(Value *V
if (ConstantInt *CI = dyn_cast<ConstantInt>(BO->getOperand(1))) {
PredValueInfoTy LHSVals;
ComputeValueKnownInPredecessors(BO->getOperand(0), BB, LHSVals,
- WantInteger);
+ WantInteger, CxtI);
// Try to use constant folding to simplify the binary operator.
for (unsigned i = 0, e = LHSVals.size(); i != e; ++i) {
@@ -512,7 +516,8 @@ ComputeValueKnownInPredecessors(Value *V
LazyValueInfo::Tristate
ResT = LVI->getPredicateOnEdge(Cmp->getPredicate(), LHS,
- cast<Constant>(RHS), PredBB, BB);
+ cast<Constant>(RHS), PredBB, BB,
+ CxtI ? CxtI : Cmp);
if (ResT == LazyValueInfo::Unknown)
continue;
Res = ConstantInt::get(Type::getInt1Ty(LHS->getContext()), ResT);
@@ -525,7 +530,6 @@ ComputeValueKnownInPredecessors(Value *V
return !Result.empty();
}
-
// If comparing a live-in value against a constant, see if we know the
// live-in value on any predecessors.
if (isa<Constant>(Cmp->getOperand(1)) && Cmp->getType()->isIntegerTy()) {
@@ -539,7 +543,7 @@ ComputeValueKnownInPredecessors(Value *V
// predecessor, use that information to try to thread this block.
LazyValueInfo::Tristate Res =
LVI->getPredicateOnEdge(Cmp->getPredicate(), Cmp->getOperand(0),
- RHSCst, P, BB);
+ RHSCst, P, BB, CxtI ? CxtI : Cmp);
if (Res == LazyValueInfo::Unknown)
continue;
@@ -555,7 +559,7 @@ ComputeValueKnownInPredecessors(Value *V
if (Constant *CmpConst = dyn_cast<Constant>(Cmp->getOperand(1))) {
PredValueInfoTy LHSVals;
ComputeValueKnownInPredecessors(I->getOperand(0), BB, LHSVals,
- WantInteger);
+ WantInteger, CxtI);
for (unsigned i = 0, e = LHSVals.size(); i != e; ++i) {
Constant *V = LHSVals[i].first;
@@ -578,7 +582,7 @@ ComputeValueKnownInPredecessors(Value *V
PredValueInfoTy Conds;
if ((TrueVal || FalseVal) &&
ComputeValueKnownInPredecessors(SI->getCondition(), BB, Conds,
- WantInteger)) {
+ WantInteger, CxtI)) {
for (unsigned i = 0, e = Conds.size(); i != e; ++i) {
Constant *Cond = Conds[i].first;
@@ -605,7 +609,7 @@ ComputeValueKnownInPredecessors(Value *V
}
// If all else fails, see if LVI can figure out a constant value for us.
- Constant *CI = LVI->getConstant(V, BB);
+ Constant *CI = LVI->getConstant(V, BB, CxtI);
if (Constant *KC = getKnownConstant(CI, Preference)) {
for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
Result.push_back(std::make_pair(KC, *PI));
@@ -745,7 +749,7 @@ bool JumpThreading::ProcessBlock(BasicBl
// All the rest of our checks depend on the condition being an instruction.
if (!CondInst) {
// FIXME: Unify this with code below.
- if (ProcessThreadableEdges(Condition, BB, Preference))
+ if (ProcessThreadableEdges(Condition, BB, Preference, Terminator))
return true;
return false;
}
@@ -767,13 +771,14 @@ bool JumpThreading::ProcessBlock(BasicBl
// FIXME: We could handle mixed true/false by duplicating code.
LazyValueInfo::Tristate Baseline =
LVI->getPredicateOnEdge(CondCmp->getPredicate(), CondCmp->getOperand(0),
- CondConst, *PI, BB);
+ CondConst, *PI, BB, CondCmp);
if (Baseline != LazyValueInfo::Unknown) {
// Check that all remaining incoming values match the first one.
while (++PI != PE) {
LazyValueInfo::Tristate Ret =
LVI->getPredicateOnEdge(CondCmp->getPredicate(),
- CondCmp->getOperand(0), CondConst, *PI, BB);
+ CondCmp->getOperand(0), CondConst, *PI, BB,
+ CondCmp);
if (Ret != Baseline) break;
}
@@ -788,6 +793,21 @@ bool JumpThreading::ProcessBlock(BasicBl
}
}
+ } else if (CondBr && CondConst && CondBr->isConditional()) {
+ // There might be an invairant in the same block with the conditional
+ // that can determine the predicate.
+
+ LazyValueInfo::Tristate Ret =
+ LVI->getPredicateAt(CondCmp->getPredicate(), CondCmp->getOperand(0),
+ CondConst, CondCmp);
+ if (Ret != LazyValueInfo::Unknown) {
+ unsigned ToRemove = Ret == LazyValueInfo::True ? 1 : 0;
+ unsigned ToKeep = Ret == LazyValueInfo::True ? 0 : 1;
+ CondBr->getSuccessor(ToRemove)->removePredecessor(BB, true);
+ BranchInst::Create(CondBr->getSuccessor(ToKeep), CondBr);
+ CondBr->eraseFromParent();
+ return true;
+ }
}
if (CondBr && CondConst && TryToUnfoldSelect(CondCmp, BB))
@@ -815,7 +835,7 @@ bool JumpThreading::ProcessBlock(BasicBl
// a PHI node in the current block. If we can prove that any predecessors
// compute a predictable value based on a PHI node, thread those predecessors.
//
- if (ProcessThreadableEdges(CondInst, BB, Preference))
+ if (ProcessThreadableEdges(CondInst, BB, Preference, Terminator))
return true;
// If this is an otherwise-unfoldable branch on a phi node in the current
@@ -1083,14 +1103,15 @@ FindMostPopularDest(BasicBlock *BB,
}
bool JumpThreading::ProcessThreadableEdges(Value *Cond, BasicBlock *BB,
- ConstantPreference Preference) {
+ ConstantPreference Preference,
+ Instruction *CxtI) {
// If threading this would thread across a loop header, don't even try to
// thread the edge.
if (LoopHeaders.count(BB))
return false;
PredValueInfoTy PredValues;
- if (!ComputeValueKnownInPredecessors(Cond, BB, PredValues, Preference))
+ if (!ComputeValueKnownInPredecessors(Cond, BB, PredValues, Preference, CxtI))
return false;
assert(!PredValues.empty() &&
@@ -1255,10 +1276,10 @@ bool JumpThreading::ProcessBranchOnXOR(B
PredValueInfoTy XorOpValues;
bool isLHS = true;
if (!ComputeValueKnownInPredecessors(BO->getOperand(0), BB, XorOpValues,
- WantInteger)) {
+ WantInteger, BO)) {
assert(XorOpValues.empty());
if (!ComputeValueKnownInPredecessors(BO->getOperand(1), BB, XorOpValues,
- WantInteger))
+ WantInteger, BO))
return false;
isLHS = false;
}
@@ -1674,10 +1695,10 @@ bool JumpThreading::TryToUnfoldSelect(Cm
// cases will be threaded in any case.
LazyValueInfo::Tristate LHSFolds =
LVI->getPredicateOnEdge(CondCmp->getPredicate(), SI->getOperand(1),
- CondRHS, Pred, BB);
+ CondRHS, Pred, BB, CondCmp);
LazyValueInfo::Tristate RHSFolds =
LVI->getPredicateOnEdge(CondCmp->getPredicate(), SI->getOperand(2),
- CondRHS, Pred, BB);
+ CondRHS, Pred, BB, CondCmp);
if ((LHSFolds != LazyValueInfo::Unknown ||
RHSFolds != LazyValueInfo::Unknown) &&
LHSFolds != RHSFolds) {
Added: llvm/trunk/test/Transforms/JumpThreading/assume.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/JumpThreading/assume.ll?rev=217345&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/JumpThreading/assume.ll (added)
+++ llvm/trunk/test/Transforms/JumpThreading/assume.ll Sun Sep 7 15:29:59 2014
@@ -0,0 +1,68 @@
+; RUN: opt -S -jump-threading -dce < %s | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: nounwind uwtable
+define i32 @test1(i32 %a, i32 %b) #0 {
+entry:
+ %cmp = icmp sgt i32 %a, 5
+ tail call void @llvm.assume(i1 %cmp)
+ %cmp1 = icmp sgt i32 %b, 1234
+ br i1 %cmp1, label %if.then, label %if.else
+
+; CHECK-LABEL: @test1
+; CHECK: icmp sgt i32 %a, 5
+; CHECK: call void @llvm.assume
+; CHECK-NOT: icmp sgt i32 %a, 3
+; CHECK: ret i32
+
+if.then: ; preds = %entry
+ %cmp2 = icmp sgt i32 %a, 3
+ br i1 %cmp2, label %if.then3, label %return
+
+if.then3: ; preds = %if.then
+ tail call void (...)* @bar() #1
+ br label %return
+
+if.else: ; preds = %entry
+ tail call void (...)* @car() #1
+ br label %return
+
+return: ; preds = %if.else, %if.then, %if.then3
+ %retval.0 = phi i32 [ 1, %if.then3 ], [ 0, %if.then ], [ 0, %if.else ]
+ ret i32 %retval.0
+}
+
+define i32 @test2(i32 %a) #0 {
+entry:
+ %cmp = icmp sgt i32 %a, 5
+ tail call void @llvm.assume(i1 %cmp)
+ %cmp1 = icmp sgt i32 %a, 3
+ br i1 %cmp1, label %if.then, label %return
+
+; CHECK-LABEL: @test2
+; CHECK: icmp sgt i32 %a, 5
+; CHECK: tail call void @llvm.assume
+; CHECK: tail call void (...)* @bar()
+; CHECK: ret i32 1
+
+
+if.then: ; preds = %entry
+ tail call void (...)* @bar() #1
+ br label %return
+
+return: ; preds = %entry, %if.then
+ %retval.0 = phi i32 [ 1, %if.then ], [ 0, %entry ]
+ ret i32 %retval.0
+}
+
+; Function Attrs: nounwind
+declare void @llvm.assume(i1) #1
+
+declare void @bar(...)
+
+declare void @car(...)
+
+attributes #0 = { nounwind uwtable }
+attributes #1 = { nounwind }
+
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