Learn ScalarReplAggregrates how stores and loads of first class aggregrates
work and how to replace them into individual values. Also, when trying to
replace an aggregrate that is used by load or store with a single (large)
integer, don't crash (but don't replace the aggregrate either).
Also adds a testcase for both structs and arrays.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51997 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/ScalarReplAggregates.cpp b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
index 2db6db7..92d1e20 100644
--- a/lib/Transforms/Scalar/ScalarReplAggregates.cpp
+++ b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
@@ -302,6 +302,41 @@
continue;
}
+ // Replace %res = load { i32, i32 }* %alloc
+ // by
+ // %load.0 = load i32* %alloc.0
+ // %insert.0 insertvalue { i32, i32 } zeroinitializer, i32 %load.0, 0
+ // %load.1 = load i32* %alloc.1
+ // %insert = insertvalue { i32, i32 } %insert.0, i32 %load.1, 1
+ // (Also works for arrays instead of structs)
+ if (LoadInst *LI = dyn_cast<LoadInst>(User)) {
+ Value *Insert = UndefValue::get(LI->getType());
+ for (unsigned i = 0, e = ElementAllocas.size(); i != e; ++i) {
+ Value *Load = new LoadInst(ElementAllocas[i], "load", LI);
+ Insert = InsertValueInst::Create(Insert, Load, i, "insert", LI);
+ }
+ LI->replaceAllUsesWith(Insert);
+ LI->eraseFromParent();
+ continue;
+ }
+
+ // Replace store { i32, i32 } %val, { i32, i32 }* %alloc
+ // by
+ // %val.0 = extractvalue { i32, i32 } %val, 0
+ // store i32 %val.0, i32* %alloc.0
+ // %val.1 = extractvalue { i32, i32 } %val, 1
+ // store i32 %val.1, i32* %alloc.1
+ // (Also works for arrays instead of structs)
+ if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
+ Value *Val = SI->getOperand(0);
+ for (unsigned i = 0, e = ElementAllocas.size(); i != e; ++i) {
+ Value *Extract = ExtractValueInst::Create(Val, i, Val->getName(), SI);
+ new StoreInst(Extract, ElementAllocas[i], SI);
+ }
+ SI->eraseFromParent();
+ continue;
+ }
+
GetElementPtrInst *GEPI = cast<GetElementPtrInst>(User);
// We now know that the GEP is of the form: GEP <ptr>, 0, <cst>
unsigned Idx =
@@ -440,6 +475,12 @@
if (BitCastInst *C = dyn_cast<BitCastInst>(User))
return isSafeUseOfBitCastedAllocation(C, AI, Info);
+ if (isa<LoadInst>(User))
+ return; // Loads (returning a first class aggregrate) are always rewritable
+
+ if (isa<StoreInst>(User) && User->getOperand(0) != AI)
+ return; // Store is ok if storing INTO the pointer, not storing the pointer
+
GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(User);
if (GEPI == 0)
return MarkUnsafe(Info);
@@ -961,12 +1002,22 @@
Instruction *User = cast<Instruction>(*UI);
if (LoadInst *LI = dyn_cast<LoadInst>(User)) {
+ // FIXME: Loads of a first class aggregrate value could be converted to a
+ // series of loads and insertvalues
+ if (!LI->getType()->isSingleValueType())
+ return 0;
+
if (MergeInType(LI->getType(), UsedType, TD))
return 0;
} else if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
// Storing the pointer, not into the value?
if (SI->getOperand(0) == V) return 0;
+
+ // FIXME: Stores of a first class aggregrate value could be converted to a
+ // series of extractvalues and stores
+ if (!SI->getOperand(0)->getType()->isSingleValueType())
+ return 0;
// NOTE: We could handle storing of FP imms into integers here!