[llvm-commits] [llvm] r50140 - in /llvm/trunk: lib/Transforms/Scalar/SCCP.cpp test/Transforms/SCCP/2008-04-22-multiple-ret-sccp.ll
Chris Lattner
sabre at nondot.org
Tue Apr 22 22:38:20 PDT 2008
Author: lattner
Date: Wed Apr 23 00:38:20 2008
New Revision: 50140
URL: http://llvm.org/viewvc/llvm-project?rev=50140&view=rev
Log:
Rewrite multiple return value handling in SCCP. Before, the -sccp pass
would turn every getresult instruction into undef. This helps with
rdar://5778210
Added:
llvm/trunk/test/Transforms/SCCP/2008-04-22-multiple-ret-sccp.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/SCCP.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/SCCP.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SCCP.cpp?rev=50140&r1=50139&r2=50140&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/SCCP.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/SCCP.cpp Wed Apr 23 00:38:20 2008
@@ -130,21 +130,6 @@
}
};
-/// LatticeValIndex - LatticeVal and associated Index. This is used
-/// to track individual operand Lattice values for multi value ret instructions.
-class VISIBILITY_HIDDEN LatticeValIndexed {
- public:
- LatticeValIndexed(unsigned I = 0) { Index = I; }
- LatticeVal &getLatticeVal() { return LV; }
- unsigned getIndex() const { return Index; }
-
- void setLatticeVal(LatticeVal &L) { LV = L; }
- void setIndex(unsigned I) { Index = I; }
-
- private:
- LatticeVal LV;
- unsigned Index;
-};
//===----------------------------------------------------------------------===//
//
/// SCCPSolver - This class is a general purpose solver for Sparse Conditional
@@ -167,7 +152,7 @@
/// TrackedMultipleRetVals - Same as TrackedRetVals, but used for functions
/// that return multiple values.
- std::multimap<Function*, LatticeValIndexed> TrackedMultipleRetVals;
+ std::map<std::pair<Function*, unsigned>, LatticeVal> TrackedMultipleRetVals;
// The reason for two worklists is that overdefined is the lowest state
// on the lattice, and moving things to overdefined as fast as possible
@@ -220,11 +205,10 @@
// Add an entry, F -> undef.
if (const StructType *STy = dyn_cast<StructType>(F->getReturnType())) {
for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
- TrackedMultipleRetVals.insert(std::pair<Function *, LatticeValIndexed>
- (F, LatticeValIndexed(i)));
- }
- else
- TrackedRetVals[F];
+ TrackedMultipleRetVals.insert(std::make_pair(std::make_pair(F, i),
+ LatticeVal()));
+ } else
+ TrackedRetVals.insert(std::make_pair(F, LatticeVal()));
}
/// Solve - Solve for constants and executable blocks.
@@ -291,7 +275,6 @@
// markOverdefined - Make a value be marked as "overdefined". If the
// value is not already overdefined, add it to the overdefined instruction
// work list so that the users of the instruction are updated later.
-
inline void markOverdefined(LatticeVal &IV, Value *V) {
if (IV.markOverdefined()) {
DEBUG(DOUT << "markOverdefined: ";
@@ -640,7 +623,7 @@
if (!F->hasInternalLinkage())
return;
- if (!TrackedRetVals.empty()) {
+ if (!TrackedRetVals.empty() && I.getNumOperands() == 1) {
DenseMap<Function*, LatticeVal>::iterator TFRVI =
TrackedRetVals.find(F);
if (TFRVI != TrackedRetVals.end() &&
@@ -651,15 +634,13 @@
}
}
- // Handle function that returns multiple values.
- std::multimap<Function*, LatticeValIndexed>::iterator It, E;
- tie(It, E) = TrackedMultipleRetVals.equal_range(F);
- if (It != E) {
- for (; It != E; ++It) {
- LatticeValIndexed &LV = It->second;
- unsigned Idx = LV.getIndex();
- Value *V = I.getOperand(Idx);
- mergeInValue(LV.getLatticeVal(), V, getValueState(V));
+ // Handle functions that return multiple values.
+ if (!TrackedMultipleRetVals.empty() && I.getNumOperands() > 1) {
+ for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i) {
+ std::map<std::pair<Function*, unsigned>, LatticeVal>::iterator
+ It = TrackedMultipleRetVals.find(std::make_pair(F, i));
+ if (It == TrackedMultipleRetVals.end()) break;
+ mergeInValue(It->second, F, getValueState(I.getOperand(i)));
}
}
}
@@ -687,28 +668,38 @@
}
void SCCPSolver::visitGetResultInst(GetResultInst &GRI) {
- unsigned Idx = GRI.getIndex();
Value *Aggr = GRI.getOperand(0);
- Function *F = NULL;
+
+ // If the operand to the getresult is an undef, the result is undef.
+ if (isa<UndefValue>(Aggr))
+ return;
+
+ Function *F;
if (CallInst *CI = dyn_cast<CallInst>(Aggr))
F = CI->getCalledFunction();
- else if (InvokeInst *II = dyn_cast<InvokeInst>(Aggr))
- F = II->getCalledFunction();
+ else
+ F = cast<InvokeInst>(Aggr)->getCalledFunction();
- if (!F)
+ // TODO: If IPSCCP resolves the callee of this function, we could propagate a
+ // result back!
+ if (F == 0 || TrackedMultipleRetVals.empty()) {
+ markOverdefined(&GRI);
return;
-
- std::multimap<Function*, LatticeValIndexed>::iterator It, E;
- tie(It, E) = TrackedMultipleRetVals.equal_range(F);
- if (It == E)
+ }
+
+ // See if we are tracking the result of the callee.
+ std::map<std::pair<Function*, unsigned>, LatticeVal>::iterator
+ It = TrackedMultipleRetVals.find(std::make_pair(F, GRI.getIndex()));
+
+ // If not tracking this function (for example, it is a declaration) just move
+ // to overdefined.
+ if (It == TrackedMultipleRetVals.end()) {
+ markOverdefined(&GRI);
return;
-
- for (; It != E; ++It) {
- LatticeValIndexed &LIV = It->second;
- if (LIV.getIndex() == Idx) {
- mergeInValue(&GRI, LIV.getLatticeVal());
- }
}
+
+ // Otherwise, the value will be merged in here as a result of CallSite
+ // handling.
}
void SCCPSolver::visitSelectInst(SelectInst &I) {
@@ -1127,79 +1118,90 @@
void SCCPSolver::visitCallSite(CallSite CS) {
Function *F = CS.getCalledFunction();
-
- DenseMap<Function*, LatticeVal>::iterator TFRVI =TrackedRetVals.end();
- // If we are tracking this function, we must make sure to bind arguments as
- // appropriate.
- bool FirstCall = false;
- if (F && F->hasInternalLinkage()) {
- TFRVI = TrackedRetVals.find(F);
- if (TFRVI != TrackedRetVals.end())
- FirstCall = true;
- else {
- std::multimap<Function*, LatticeValIndexed>::iterator It, E;
- tie(It, E) = TrackedMultipleRetVals.equal_range(F);
- if (It != E)
- FirstCall = true;
- }
- }
-
- if (FirstCall) {
- // If this is the first call to the function hit, mark its entry block
- // executable.
- if (!BBExecutable.count(F->begin()))
- MarkBlockExecutable(F->begin());
+ Instruction *I = CS.getInstruction();
+
+ // The common case is that we aren't tracking the callee, either because we
+ // are not doing interprocedural analysis or the callee is indirect, or is
+ // external. Handle these cases first.
+ if (F == 0 || !F->hasInternalLinkage()) {
+CallOverdefined:
+ // Void return and not tracking callee, just bail.
+ if (I->getType() == Type::VoidTy) return;
- CallSite::arg_iterator CAI = CS.arg_begin();
- for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
- AI != E; ++AI, ++CAI) {
- LatticeVal &IV = ValueState[AI];
- if (!IV.isOverdefined())
- mergeInValue(IV, AI, getValueState(*CAI));
+ // Otherwise, if we have a single return value case, and if the function is
+ // a declaration, maybe we can constant fold it.
+ if (!isa<StructType>(I->getType()) && F && F->isDeclaration() &&
+ canConstantFoldCallTo(F)) {
+
+ SmallVector<Constant*, 8> Operands;
+ for (CallSite::arg_iterator AI = CS.arg_begin(), E = CS.arg_end();
+ AI != E; ++AI) {
+ LatticeVal &State = getValueState(*AI);
+ if (State.isUndefined())
+ return; // Operands are not resolved yet.
+ else if (State.isOverdefined()) {
+ markOverdefined(I);
+ return;
+ }
+ assert(State.isConstant() && "Unknown state!");
+ Operands.push_back(State.getConstant());
+ }
+
+ // If we can constant fold this, mark the result of the call as a
+ // constant.
+ if (Constant *C = ConstantFoldCall(F, &Operands[0], Operands.size())) {
+ markConstant(I, C);
+ return;
+ }
}
- }
- Instruction *I = CS.getInstruction();
-
- if (!CS.doesNotThrow() && I->getParent()->getUnwindDest())
- markEdgeExecutable(I->getParent(), I->getParent()->getUnwindDest());
-
- if (I->getType() == Type::VoidTy) return;
-
- LatticeVal &IV = ValueState[I];
- if (IV.isOverdefined()) return;
- // Propagate the single return value of the function to the value of the
- // instruction.
- if (TFRVI != TrackedRetVals.end()) {
- mergeInValue(IV, I, TFRVI->second);
+ // Otherwise, we don't know anything about this call, mark it overdefined.
+ markOverdefined(I);
return;
}
- if (F == 0 || !F->isDeclaration() || !canConstantFoldCallTo(F)) {
- markOverdefined(IV, I);
- return;
- }
-
- SmallVector<Constant*, 8> Operands;
- Operands.reserve(I->getNumOperands()-1);
-
- for (CallSite::arg_iterator AI = CS.arg_begin(), E = CS.arg_end();
- AI != E; ++AI) {
- LatticeVal &State = getValueState(*AI);
- if (State.isUndefined())
- return; // Operands are not resolved yet...
- else if (State.isOverdefined()) {
- markOverdefined(IV, I);
- return;
+ // If this is a single/zero retval case, see if we're tracking the function.
+ const StructType *RetSTy = dyn_cast<StructType>(I->getType());
+ if (RetSTy == 0) {
+ // Check to see if we're tracking this callee, if not, handle it in the
+ // common path above.
+ DenseMap<Function*, LatticeVal>::iterator TFRVI = TrackedRetVals.find(F);
+ if (TFRVI == TrackedRetVals.end())
+ goto CallOverdefined;
+
+ // If so, propagate the return value of the callee into this call result.
+ mergeInValue(I, TFRVI->second);
+ } else {
+ // Check to see if we're tracking this callee, if not, handle it in the
+ // common path above.
+ std::map<std::pair<Function*, unsigned>, LatticeVal>::iterator
+ TMRVI = TrackedMultipleRetVals.find(std::make_pair(F, 0));
+ if (TMRVI == TrackedMultipleRetVals.end())
+ goto CallOverdefined;
+
+ // If we are tracking this callee, propagate the return values of the call
+ // into this call site. We do this by walking all the getresult uses.
+ for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
+ UI != E; ++UI) {
+ GetResultInst *GRI = cast<GetResultInst>(*UI);
+ mergeInValue(GRI,
+ TrackedMultipleRetVals[std::make_pair(F, GRI->getIndex())]);
}
- assert(State.isConstant() && "Unknown state!");
- Operands.push_back(State.getConstant());
}
-
- if (Constant *C = ConstantFoldCall(F, &Operands[0], Operands.size()))
- markConstant(IV, I, C);
- else
- markOverdefined(IV, I);
+
+ // Finally, if this is the first call to the function hit, mark its entry
+ // block executable.
+ if (!BBExecutable.count(F->begin()))
+ MarkBlockExecutable(F->begin());
+
+ // Propagate information from this call site into the callee.
+ CallSite::arg_iterator CAI = CS.arg_begin();
+ for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
+ AI != E; ++AI, ++CAI) {
+ LatticeVal &IV = ValueState[AI];
+ if (!IV.isOverdefined())
+ mergeInValue(IV, AI, getValueState(*CAI));
+ }
}
Added: llvm/trunk/test/Transforms/SCCP/2008-04-22-multiple-ret-sccp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SCCP/2008-04-22-multiple-ret-sccp.ll?rev=50140&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/SCCP/2008-04-22-multiple-ret-sccp.ll (added)
+++ llvm/trunk/test/Transforms/SCCP/2008-04-22-multiple-ret-sccp.ll Wed Apr 23 00:38:20 2008
@@ -0,0 +1,11 @@
+; RUN: llvm-as < %s | opt -sccp | llvm-dis | grep {ret i32 %Z}
+; rdar://5778210
+
+declare {i32, i32} @bar(i32 %A)
+
+define i32 @foo() {
+ %X = call {i32, i32} @bar(i32 17)
+ %Y = getresult {i32, i32} %X, 0
+ %Z = add i32 %Y, %Y
+ ret i32 %Z
+}
More information about the llvm-commits
mailing list