summaryrefslogtreecommitdiffstats
path: root/llvm/lib/Transforms
diff options
context:
space:
mode:
Diffstat (limited to 'llvm/lib/Transforms')
-rw-r--r--llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp86
1 files changed, 47 insertions, 39 deletions
diff --git a/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp b/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
index 365555b78c5..50698bb26c8 100644
--- a/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
+++ b/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
@@ -387,14 +387,32 @@ bool DAE::RemoveDeadArgumentsFromCallers(Function &Fn)
/// for void functions and 1 for functions not returning a struct. It returns
/// the number of struct elements for functions returning a struct.
static unsigned NumRetVals(const Function *F) {
- if (F->getReturnType()->isVoidTy())
+ Type *RetTy = F->getReturnType();
+ if (RetTy->isVoidTy())
return 0;
- else if (StructType *STy = dyn_cast<StructType>(F->getReturnType()))
+ else if (StructType *STy = dyn_cast<StructType>(RetTy))
return STy->getNumElements();
+ else if (ArrayType *ATy = dyn_cast<ArrayType>(RetTy))
+ return ATy->getNumElements();
else
return 1;
}
+/// Returns the sub-type a function will return at a given Idx. Should
+/// correspond to the result type of an ExtractValue instruction executed with
+/// just that one Idx (i.e. only top-level structure is considered).
+static Type *getRetComponentType(const Function *F, unsigned Idx) {
+ Type *RetTy = F->getReturnType();
+ assert(!RetTy->isVoidTy() && "void type has no subtype");
+
+ if (StructType *STy = dyn_cast<StructType>(RetTy))
+ return STy->getElementType(Idx);
+ else if (ArrayType *ATy = dyn_cast<ArrayType>(RetTy))
+ return ATy->getElementType();
+ else
+ return RetTy;
+}
+
/// MarkIfNotLive - This checks Use for liveness in LiveValues. If Use is not
/// live, it adds Use to the MaybeLiveUses argument. Returns the determined
/// liveness of Use.
@@ -775,39 +793,29 @@ bool DAE::RemoveDeadStuffFromFunction(Function *F) {
if (RetTy->isVoidTy() || HasLiveReturnedArg) {
NRetTy = RetTy;
} else {
- StructType *STy = dyn_cast<StructType>(RetTy);
- if (STy)
- // Look at each of the original return values individually.
- for (unsigned i = 0; i != RetCount; ++i) {
- RetOrArg Ret = CreateRet(F, i);
- if (LiveValues.erase(Ret)) {
- RetTypes.push_back(STy->getElementType(i));
- NewRetIdxs[i] = RetTypes.size() - 1;
- } else {
- ++NumRetValsEliminated;
- DEBUG(dbgs() << "DAE - Removing return value " << i << " from "
- << F->getName() << "\n");
- }
- }
- else
- // We used to return a single value.
- if (LiveValues.erase(CreateRet(F, 0))) {
- RetTypes.push_back(RetTy);
- NewRetIdxs[0] = 0;
+ // Look at each of the original return values individually.
+ for (unsigned i = 0; i != RetCount; ++i) {
+ RetOrArg Ret = CreateRet(F, i);
+ if (LiveValues.erase(Ret)) {
+ RetTypes.push_back(getRetComponentType(F, i));
+ NewRetIdxs[i] = RetTypes.size() - 1;
} else {
- DEBUG(dbgs() << "DAE - Removing return value from " << F->getName()
- << "\n");
++NumRetValsEliminated;
+ DEBUG(dbgs() << "DAE - Removing return value " << i << " from "
+ << F->getName() << "\n");
+ }
+ }
+ if (RetTypes.size() > 1) {
+ // More than one return type? Reduce it down to size.
+ if (StructType *STy = dyn_cast<StructType>(RetTy)) {
+ // Make the new struct packed if we used to return a packed struct
+ // already.
+ NRetTy = StructType::get(STy->getContext(), RetTypes, STy->isPacked());
+ } else {
+ assert(isa<ArrayType>(RetTy) && "unexpected multi-value return");
+ NRetTy = ArrayType::get(RetTypes[0], RetTypes.size());
}
- if (RetTypes.size() > 1)
- // More than one return type? Return a struct with them. Also, if we used
- // to return a struct and didn't change the number of return values,
- // return a struct again. This prevents changing {something} into
- // something and {} into void.
- // Make the new struct packed if we used to return a packed struct
- // already.
- NRetTy = StructType::get(STy->getContext(), RetTypes, STy->isPacked());
- else if (RetTypes.size() == 1)
+ } else if (RetTypes.size() == 1)
// One return type? Just a simple value then, but only if we didn't use to
// return a struct with that simple value before.
NRetTy = RetTypes.front();
@@ -959,9 +967,9 @@ bool DAE::RemoveDeadStuffFromFunction(Function *F) {
if (!Call->getType()->isX86_MMXTy())
Call->replaceAllUsesWith(Constant::getNullValue(Call->getType()));
} else {
- assert(RetTy->isStructTy() &&
+ assert((RetTy->isStructTy() || RetTy->isArrayTy()) &&
"Return type changed, but not into a void. The old return type"
- " must have been a struct!");
+ " must have been a struct or an array!");
Instruction *InsertPt = Call;
if (InvokeInst *II = dyn_cast<InvokeInst>(Call)) {
BasicBlock::iterator IP = II->getNormalDest()->begin();
@@ -969,9 +977,9 @@ bool DAE::RemoveDeadStuffFromFunction(Function *F) {
InsertPt = IP;
}
- // We used to return a struct. Instead of doing smart stuff with all the
- // uses of this struct, we will just rebuild it using
- // extract/insertvalue chaining and let instcombine clean that up.
+ // We used to return a struct or array. Instead of doing smart stuff
+ // with all the uses, we will just rebuild it using extract/insertvalue
+ // chaining and let instcombine clean that up.
//
// Start out building up our return value from undef
Value *RetVal = UndefValue::get(RetTy);
@@ -1034,8 +1042,8 @@ bool DAE::RemoveDeadStuffFromFunction(Function *F) {
if (NFTy->getReturnType()->isVoidTy()) {
RetVal = nullptr;
} else {
- assert (RetTy->isStructTy());
- // The original return value was a struct, insert
+ assert(RetTy->isStructTy() || RetTy->isArrayTy());
+ // The original return value was a struct or array, insert
// extractvalue/insertvalue chains to extract only the values we need
// to return and insert them into our new result.
// This does generate messy code, but we'll let it to instcombine to
OpenPOWER on IntegriCloud