Unpack array of all sizes in InstCombine
Summary: This is another step toward improving fca support. This unpack load of array in a series of load to array's elements.
Reviewers: chandlerc, joker.eph, majnemer, reames, hfinkel
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D15890
llvm-svn: 262521
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
index 3a137a9..c559d93 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -574,13 +574,46 @@
}
if (auto *AT = dyn_cast<ArrayType>(T)) {
- // If the array only have one element, we unpack.
- if (AT->getNumElements() == 1) {
- LoadInst *NewLoad = combineLoadToNewType(IC, LI, AT->getElementType(),
- ".unpack");
+ auto *ET = AT->getElementType();
+ auto NumElements = AT->getNumElements();
+ if (NumElements == 1) {
+ LoadInst *NewLoad = combineLoadToNewType(IC, LI, ET, ".unpack");
return IC.replaceInstUsesWith(LI, IC.Builder->CreateInsertValue(
- UndefValue::get(T), NewLoad, 0, LI.getName()));
+ UndefValue::get(T), NewLoad, 0, Name));
}
+
+ const DataLayout &DL = IC.getDataLayout();
+ auto EltSize = DL.getTypeAllocSize(ET);
+ auto Align = LI.getAlignment();
+ if (!Align)
+ Align = DL.getABITypeAlignment(T);
+
+ SmallString<16> LoadName = Name;
+ LoadName += ".unpack";
+ SmallString<16> EltName = Name;
+ EltName += ".elt";
+
+ auto *Addr = LI.getPointerOperand();
+ auto *IdxType = Type::getInt64Ty(T->getContext());
+ auto *Zero = ConstantInt::get(IdxType, 0);
+
+ Value *V = UndefValue::get(T);
+ uint64_t Offset = 0;
+ for (uint64_t i = 0; i < NumElements; i++) {
+ Value *Indices[2] = {
+ Zero,
+ ConstantInt::get(IdxType, i),
+ };
+ auto *Ptr = IC.Builder->CreateInBoundsGEP(AT, Addr, makeArrayRef(Indices),
+ EltName);
+ auto *L = IC.Builder->CreateAlignedLoad(Ptr, MinAlign(Align, Offset),
+ LoadName);
+ V = IC.Builder->CreateInsertValue(V, L, i);
+ Offset += EltSize;
+ }
+
+ V->setName(Name);
+ return IC.replaceInstUsesWith(LI, V);
}
return nullptr;