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-rw-r--r--llvm/include/llvm/Analysis/MustExecute.h46
-rw-r--r--llvm/lib/Analysis/MustExecute.cpp16
-rw-r--r--llvm/lib/Transforms/Scalar/LICM.cpp2
-rw-r--r--llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp2
-rw-r--r--llvm/lib/Transforms/Scalar/LoopUnswitch.cpp2
-rw-r--r--llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp2
6 files changed, 48 insertions, 22 deletions
diff --git a/llvm/include/llvm/Analysis/MustExecute.h b/llvm/include/llvm/Analysis/MustExecute.h
index d78b38bdead..6a6a127b7c3 100644
--- a/llvm/include/llvm/Analysis/MustExecute.h
+++ b/llvm/include/llvm/Analysis/MustExecute.h
@@ -45,10 +45,6 @@ class Loop;
/// loop were made and the info wasn't recomputed properly, the behavior of all
/// methods except for computeLoopSafetyInfo is undefined.
class LoopSafetyInfo {
- bool MayThrow = false; // The current loop contains an instruction which
- // may throw.
- bool HeaderMayThrow = false; // Same as previous, but specific to loop header
-
// Used to update funclet bundle operands.
DenseMap<BasicBlock *, ColorVector> BlockColors;
@@ -73,15 +69,15 @@ public:
/// Returns true iff the header block of the loop for which this info is
/// calculated contains an instruction that may throw or otherwise exit
/// abnormally.
- bool headerMayThrow() const;
+ virtual bool headerMayThrow() const = 0;
/// Returns true iff the block \p BB potentially may throw exception. It can
/// be false-positive in cases when we want to avoid complex analysis.
- bool blockMayThrow(const BasicBlock *BB) const;
+ virtual bool blockMayThrow(const BasicBlock *BB) const = 0;
/// Returns true iff any block of the loop for which this info is contains an
/// instruction that may throw or otherwise exit abnormally.
- bool anyBlockMayThrow() const;
+ virtual bool anyBlockMayThrow() const = 0;
/// Return true if we must reach the block \p BB under assumption that the
/// loop \p CurLoop is entered.
@@ -93,14 +89,44 @@ public:
/// as argument. Updates safety information in LoopSafetyInfo argument.
/// Note: This is defined to clear and reinitialize an already initialized
/// LoopSafetyInfo. Some callers rely on this fact.
- void computeLoopSafetyInfo(const Loop *CurLoop);
+ virtual void computeLoopSafetyInfo(const Loop *CurLoop) = 0;
/// Returns true if the instruction in a loop is guaranteed to execute at
/// least once (under the assumption that the loop is entered).
- bool isGuaranteedToExecute(const Instruction &Inst, const DominatorTree *DT,
- const Loop *CurLoop) const;
+ virtual bool isGuaranteedToExecute(const Instruction &Inst,
+ const DominatorTree *DT,
+ const Loop *CurLoop) const = 0;
LoopSafetyInfo() = default;
+
+ virtual ~LoopSafetyInfo() = default;
+};
+
+
+/// Simple and conservative implementation of LoopSafetyInfo that can give
+/// false-positive answers to its queries in order to avoid complicated
+/// analysis.
+class SimpleLoopSafetyInfo: public LoopSafetyInfo {
+ bool MayThrow = false; // The current loop contains an instruction which
+ // may throw.
+ bool HeaderMayThrow = false; // Same as previous, but specific to loop header
+
+public:
+ virtual bool headerMayThrow() const;
+
+ virtual bool blockMayThrow(const BasicBlock *BB) const;
+
+ virtual bool anyBlockMayThrow() const;
+
+ virtual void computeLoopSafetyInfo(const Loop *CurLoop);
+
+ virtual bool isGuaranteedToExecute(const Instruction &Inst,
+ const DominatorTree *DT,
+ const Loop *CurLoop) const;
+
+ SimpleLoopSafetyInfo() : LoopSafetyInfo() {};
+
+ virtual ~SimpleLoopSafetyInfo() {};
};
}
diff --git a/llvm/lib/Analysis/MustExecute.cpp b/llvm/lib/Analysis/MustExecute.cpp
index bce941be26c..618e2e3e30d 100644
--- a/llvm/lib/Analysis/MustExecute.cpp
+++ b/llvm/lib/Analysis/MustExecute.cpp
@@ -33,20 +33,20 @@ void LoopSafetyInfo::copyColors(BasicBlock *New, BasicBlock *Old) {
ColorsForNewBlock = ColorsForOldBlock;
}
-bool LoopSafetyInfo::headerMayThrow() const {
+bool SimpleLoopSafetyInfo::headerMayThrow() const {
return HeaderMayThrow;
}
-bool LoopSafetyInfo::blockMayThrow(const BasicBlock *BB) const {
+bool SimpleLoopSafetyInfo::blockMayThrow(const BasicBlock *BB) const {
(void)BB;
return anyBlockMayThrow();
}
-bool LoopSafetyInfo::anyBlockMayThrow() const {
+bool SimpleLoopSafetyInfo::anyBlockMayThrow() const {
return MayThrow;
}
-void LoopSafetyInfo::computeLoopSafetyInfo(const Loop *CurLoop) {
+void SimpleLoopSafetyInfo::computeLoopSafetyInfo(const Loop *CurLoop) {
assert(CurLoop != nullptr && "CurLoop can't be null");
BasicBlock *Header = CurLoop->getHeader();
// Iterate over header and compute safety info.
@@ -200,9 +200,9 @@ bool LoopSafetyInfo::allLoopPathsLeadToBlock(const Loop *CurLoop,
/// Returns true if the instruction in a loop is guaranteed to execute at least
/// once.
-bool LoopSafetyInfo::isGuaranteedToExecute(const Instruction &Inst,
- const DominatorTree *DT,
- const Loop *CurLoop) const {
+bool SimpleLoopSafetyInfo::isGuaranteedToExecute(const Instruction &Inst,
+ const DominatorTree *DT,
+ const Loop *CurLoop) const {
// We have to check to make sure that the instruction dominates all
// of the exit blocks. If it doesn't, then there is a path out of the loop
// which does not execute this instruction, so we can't hoist it.
@@ -259,7 +259,7 @@ static bool isMustExecuteIn(const Instruction &I, Loop *L, DominatorTree *DT) {
// TODO: merge these two routines. For the moment, we display the best
// result obtained by *either* implementation. This is a bit unfair since no
// caller actually gets the full power at the moment.
- LoopSafetyInfo LSI;
+ SimpleLoopSafetyInfo LSI;
LSI.computeLoopSafetyInfo(L);
return LSI.isGuaranteedToExecute(I, DT, L) ||
isGuaranteedToExecuteForEveryIteration(&I, L);
diff --git a/llvm/lib/Transforms/Scalar/LICM.cpp b/llvm/lib/Transforms/Scalar/LICM.cpp
index 6c899289593..e72342b88b6 100644
--- a/llvm/lib/Transforms/Scalar/LICM.cpp
+++ b/llvm/lib/Transforms/Scalar/LICM.cpp
@@ -267,7 +267,7 @@ bool LoopInvariantCodeMotion::runOnLoop(
BasicBlock *Preheader = L->getLoopPreheader();
// Compute loop safety information.
- LoopSafetyInfo SafetyInfo;
+ SimpleLoopSafetyInfo SafetyInfo;
SafetyInfo.computeLoopSafetyInfo(L);
// We want to visit all of the instructions in this loop... that are not parts
diff --git a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
index 9a45551f64b..4b375956a12 100644
--- a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -320,7 +320,7 @@ bool LoopIdiomRecognize::runOnCountableLoop() {
// The following transforms hoist stores/memsets into the loop pre-header.
// Give up if the loop has instructions may throw.
- LoopSafetyInfo SafetyInfo;
+ SimpleLoopSafetyInfo SafetyInfo;
SafetyInfo.computeLoopSafetyInfo(CurLoop);
if (SafetyInfo.anyBlockMayThrow())
return MadeChange;
diff --git a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
index cd49f51283f..4a089dfa7db 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
@@ -189,7 +189,7 @@ namespace {
BasicBlock *loopPreheader = nullptr;
bool SanitizeMemory;
- LoopSafetyInfo SafetyInfo;
+ SimpleLoopSafetyInfo SafetyInfo;
// LoopBlocks contains all of the basic blocks of the loop, including the
// preheader of the loop, the body of the loop, and the exit blocks of the
diff --git a/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp b/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
index c17a64f0187..8949c603a84 100644
--- a/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
@@ -761,7 +761,7 @@ bool llvm::isSafeToUnrollAndJam(Loop *L, ScalarEvolution &SE, DominatorTree &DT,
}
// Check the loop safety info for exceptions.
- LoopSafetyInfo LSI;
+ SimpleLoopSafetyInfo LSI;
LSI.computeLoopSafetyInfo(L);
if (LSI.anyBlockMayThrow()) {
LLVM_DEBUG(dbgs() << "Won't unroll-and-jam; Something may throw\n");
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