Misc mid-level changes for new 'fence' instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136205 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/Analysis/AliasAnalysis.h b/include/llvm/Analysis/AliasAnalysis.h
index 2701b52..c86aa03 100644
--- a/include/llvm/Analysis/AliasAnalysis.h
+++ b/include/llvm/Analysis/AliasAnalysis.h
@@ -341,6 +341,7 @@
case Instruction::VAArg: return getModRefInfo((const VAArgInst*)I, Loc);
case Instruction::Load: return getModRefInfo((const LoadInst*)I, Loc);
case Instruction::Store: return getModRefInfo((const StoreInst*)I, Loc);
+ case Instruction::Fence: return getModRefInfo((const FenceInst*)I, Loc);
case Instruction::Call: return getModRefInfo((const CallInst*)I, Loc);
case Instruction::Invoke: return getModRefInfo((const InvokeInst*)I,Loc);
default: return NoModRef;
@@ -406,6 +407,19 @@
return getModRefInfo(S, Location(P, Size));
}
+ /// getModRefInfo (for fences) - Return whether information about whether
+ /// a particular store modifies or reads the specified memory location.
+ ModRefResult getModRefInfo(const FenceInst *S, const Location &Loc) {
+ // Conservatively correct. (We could possibly be a bit smarter if
+ // Loc is a alloca that doesn't escape.)
+ return ModRef;
+ }
+
+ /// getModRefInfo (for fences) - A convenience wrapper.
+ ModRefResult getModRefInfo(const FenceInst *S, const Value *P, uint64_t Size){
+ return getModRefInfo(S, Location(P, Size));
+ }
+
/// getModRefInfo (for va_args) - Return whether information about whether
/// a particular va_arg modifies or reads the specified memory location.
ModRefResult getModRefInfo(const VAArgInst* I, const Location &Loc);
diff --git a/lib/Transforms/Scalar/DeadStoreElimination.cpp b/lib/Transforms/Scalar/DeadStoreElimination.cpp
index e6089a9..a645f92 100644
--- a/lib/Transforms/Scalar/DeadStoreElimination.cpp
+++ b/lib/Transforms/Scalar/DeadStoreElimination.cpp
@@ -665,7 +665,7 @@
continue;
}
-
+
AliasAnalysis::Location LoadedLoc;
// If we encounter a use of the pointer, it is no longer considered dead
@@ -675,9 +675,12 @@
LoadedLoc = AA->getLocation(V);
} else if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(BBI)) {
LoadedLoc = AA->getLocationForSource(MTI);
- } else {
- // Not a loading instruction.
+ } else if (!BBI->mayReadOrWriteMemory()) {
+ // Instruction doesn't touch memory.
continue;
+ } else {
+ // Unknown inst; assume it clobbers everything.
+ break;
}
// Remove any allocas from the DeadPointer set that are loaded, as this
diff --git a/lib/Transforms/Scalar/LowerAtomic.cpp b/lib/Transforms/Scalar/LowerAtomic.cpp
index 9087b46..7f4d9e9 100644
--- a/lib/Transforms/Scalar/LowerAtomic.cpp
+++ b/lib/Transforms/Scalar/LowerAtomic.cpp
@@ -115,6 +115,11 @@
return true;
}
+static bool LowerFenceInst(FenceInst *FI) {
+ FI->eraseFromParent();
+ return true;
+}
+
namespace {
struct LowerAtomic : public BasicBlockPass {
static char ID;
@@ -123,9 +128,13 @@
}
bool runOnBasicBlock(BasicBlock &BB) {
bool Changed = false;
- for (BasicBlock::iterator DI = BB.begin(), DE = BB.end(); DI != DE; )
- if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(DI++))
+ for (BasicBlock::iterator DI = BB.begin(), DE = BB.end(); DI != DE; ) {
+ Instruction *Inst = DI++;
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst))
Changed |= LowerAtomicIntrinsic(II);
+ if (FenceInst *FI = dyn_cast<FenceInst>(Inst))
+ Changed |= LowerFenceInst(FI);
+ }
return Changed;
}
};
diff --git a/lib/Transforms/Scalar/SCCP.cpp b/lib/Transforms/Scalar/SCCP.cpp
index 67570e6..749ba40 100644
--- a/lib/Transforms/Scalar/SCCP.cpp
+++ b/lib/Transforms/Scalar/SCCP.cpp
@@ -530,6 +530,7 @@
void visitCallSite (CallSite CS);
void visitUnwindInst (TerminatorInst &I) { /*returns void*/ }
void visitUnreachableInst(TerminatorInst &I) { /*returns void*/ }
+ void visitFenceInst (FenceInst &I) { /*returns void*/ }
void visitAllocaInst (Instruction &I) { markOverdefined(&I); }
void visitVAArgInst (Instruction &I) { markAnythingOverdefined(&I); }
diff --git a/lib/VMCore/Instruction.cpp b/lib/VMCore/Instruction.cpp
index 4597b57..cd8f737 100644
--- a/lib/VMCore/Instruction.cpp
+++ b/lib/VMCore/Instruction.cpp
@@ -209,6 +209,9 @@
return IVI->getIndices() == cast<InsertValueInst>(I)->getIndices();
if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(this))
return EVI->getIndices() == cast<ExtractValueInst>(I)->getIndices();
+ if (const FenceInst *FI = dyn_cast<FenceInst>(this))
+ return FI->getOrdering() == cast<FenceInst>(FI)->getOrdering() &&
+ FI->getSynchScope() == cast<FenceInst>(FI)->getSynchScope();
return true;
}
@@ -249,6 +252,9 @@
return IVI->getIndices() == cast<InsertValueInst>(I)->getIndices();
if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(this))
return EVI->getIndices() == cast<ExtractValueInst>(I)->getIndices();
+ if (const FenceInst *FI = dyn_cast<FenceInst>(this))
+ return FI->getOrdering() == cast<FenceInst>(FI)->getOrdering() &&
+ FI->getSynchScope() == cast<FenceInst>(FI)->getSynchScope();
return true;
}
@@ -281,6 +287,7 @@
default: return false;
case Instruction::VAArg:
case Instruction::Load:
+ case Instruction::Fence: // FIXME: refine definition of mayReadFromMemory
return true;
case Instruction::Call:
return !cast<CallInst>(this)->doesNotAccessMemory();
@@ -296,6 +303,7 @@
bool Instruction::mayWriteToMemory() const {
switch (getOpcode()) {
default: return false;
+ case Instruction::Fence: // FIXME: refine definition of mayWriteToMemory
case Instruction::Store:
case Instruction::VAArg:
return true;
@@ -393,6 +401,7 @@
case Switch:
case Unwind:
case Unreachable:
+ case Fence:
return false; // Misc instructions which have effects
}
}