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Move the deadargelim code for intrinsically alive functions into its own

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method, to slightly simplify control flow.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53591 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Matthijs Kooijman 2008-07-15 08:45:12 +00:00
parent 2920d2b7b6
commit a3ec5d6ecc
1 changed files with 25 additions and 23 deletions
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48
lib/Transforms/IPO/DeadArgumentElimination.cpp
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@ -133,6 +133,7 @@ namespace {
void MarkValue(const RetOrArg &RA, Liveness L,
const UseVector &MaybeLiveUses);
void MarkLive(RetOrArg RA);
void MarkLive(const Function &F);
bool RemoveDeadStuffFromFunction(Function *F);
bool DeleteDeadVarargs(Function &Fn);
};
@ -397,7 +398,6 @@ DAE::Liveness DAE::SurveyUses(Value *V, UseVector &MaybeLiveUses) {
// well as arguments to functions which have their "address taken".
//
void DAE::SurveyFunction(Function &F) {
bool FunctionIntrinsicallyLive = false;
unsigned RetCount = NumRetVals(&F);
// Assume all return values are dead
typedef SmallVector<Liveness, 5> RetVals;
@ -414,14 +414,15 @@ void DAE::SurveyFunction(Function &F) {
if (RI->getNumOperands() != 0 && RI->getOperand(0)->getType()
!= F.getFunctionType()->getReturnType()) {
// We don't support old style multiple return values.
FunctionIntrinsicallyLive = true;
break;
MarkLive(F);
return;
}
if (!F.hasInternalLinkage() && (!ShouldHackArguments() || F.isIntrinsic()))
FunctionIntrinsicallyLive = true;
if (!F.hasInternalLinkage() && (!ShouldHackArguments() || F.isIntrinsic())) {
MarkLive(F);
return;
}
if (!FunctionIntrinsicallyLive) {
DOUT << "DAE - Inspecting callers for fn: " << F.getName() << "\n";
// Keep track of the number of live retvals, so we can skip checks once all
// of them turn out to be live.
@ -432,16 +433,16 @@ void DAE::SurveyFunction(Function &F) {
// If the function is PASSED IN as an argument, its address has been
// taken.
if (I.getOperandNo() != 0) {
FunctionIntrinsicallyLive = true;
break;
MarkLive(F);
return;
}
// If this use is anything other than a call site, the function is alive.
CallSite CS = CallSite::get(*I);
Instruction *TheCall = CS.getInstruction();
if (!TheCall) { // Not a direct call site?
FunctionIntrinsicallyLive = true;
break;
MarkLive(F);
return;
}
// If we end up here, we are looking at a direct call to our function.
@ -480,19 +481,6 @@ void DAE::SurveyFunction(Function &F) {
}
}
}
}
if (FunctionIntrinsicallyLive) {
DOUT << "DAE - Intrinsically live fn: " << F.getName() << "\n";
// Mark all arguments as live.
unsigned i = 0;
for (unsigned i = 0, e = F.arg_size(); i != e; ++i)
MarkLive(CreateArg(&F, i));
// Mark all return values as live.
i = 0;
for (unsigned i = 0; i != RetCount; ++i)
MarkLive(CreateRet(&F, i));
return;
}
// Now we've inspected all callers, record the liveness of our return values.
for (unsigned i = 0; i != RetCount; ++i)
@ -535,6 +523,20 @@ void DAE::MarkValue(const RetOrArg &RA, Liveness L,
}
}
/// MarkLive - Mark the given Function as alive, meaning that it cannot be
/// changed in any way. Additionally,
/// mark any values that are used as this function's parameters or by its return
/// values (according to Uses) live as well.
void DAE::MarkLive(const Function &F) {
DOUT << "DAE - Intrinsically live fn: " << F.getName() << "\n";
// Mark all arguments as live.
for (unsigned i = 0, e = F.arg_size(); i != e; ++i)
MarkLive(CreateArg(&F, i));
// Mark all return values as live.
for (unsigned i = 0, e = NumRetVals(&F); i != e; ++i)
MarkLive(CreateRet(&F, i));
}
/// MarkLive - Mark the given return value or argument as live. Additionally,
/// mark any values that are used by this value (according to Uses) live as
/// well.