Allow SROA to split up an array of vectors into multiple vectors, even when the vectors are dynamically indexed
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158529 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/ScalarReplAggregates.cpp b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
index a6c3a5e..9fc4164 100644
--- a/lib/Transforms/Scalar/ScalarReplAggregates.cpp
+++ b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
@@ -1642,6 +1642,8 @@
gep_type_iterator GEPIt = gep_type_begin(GEPI), E = gep_type_end(GEPI);
if (GEPIt == E)
return;
+ bool NonConstant = false;
+ unsigned NonConstantIdxSize = 0;
// Walk through the GEP type indices, checking the types that this indexes
// into.
@@ -1651,15 +1653,30 @@
continue;
ConstantInt *IdxVal = dyn_cast<ConstantInt>(GEPIt.getOperand());
- if (!IdxVal)
- return MarkUnsafe(Info, GEPI);
+ if (!IdxVal) {
+ // Non constant GEPs are only a problem on arrays, structs, and pointers
+ // Vectors can be dynamically indexed.
+ // FIXME: Add support for dynamic indexing on arrays. This should be
+ // ok on any subarrays of the alloca array, eg, a[0][i] is ok, but a[i][0]
+ // isn't.
+ if (!(*GEPIt)->isVectorTy())
+ return MarkUnsafe(Info, GEPI);
+ NonConstant = true;
+ NonConstantIdxSize = TD->getTypeAllocSize(*GEPIt);
+ }
}
// Compute the offset due to this GEP and check if the alloca has a
// component element at that offset.
SmallVector<Value*, 8> Indices(GEPI->op_begin() + 1, GEPI->op_end());
+ // If this GEP is non constant then the last operand must have been a
+ // dynamic index into a vector. Pop this now as it has no impact on the
+ // constant part of the offset.
+ if (NonConstant)
+ Indices.pop_back();
Offset += TD->getIndexedOffset(GEPI->getPointerOperandType(), Indices);
- if (!TypeHasComponent(Info.AI->getAllocatedType(), Offset, 0))
+ if (!TypeHasComponent(Info.AI->getAllocatedType(), Offset,
+ NonConstantIdxSize))
MarkUnsafe(Info, GEPI);
}
@@ -1961,6 +1978,13 @@
SmallVector<AllocaInst*, 32> &NewElts) {
uint64_t OldOffset = Offset;
SmallVector<Value*, 8> Indices(GEPI->op_begin() + 1, GEPI->op_end());
+ // If the GEP was dynamic then it must have been a dynamic vector lookup.
+ // In this case, it must be the last GEP operand which is dynamic so keep that
+ // aside until we've found the constant GEP offset then add it back in at the
+ // end.
+ Value* NonConstantIdx = 0;
+ if (!GEPI->hasAllConstantIndices())
+ NonConstantIdx = Indices.pop_back_val();
Offset += TD->getIndexedOffset(GEPI->getPointerOperandType(), Indices);
RewriteForScalarRepl(GEPI, AI, Offset, NewElts);
@@ -1987,6 +2011,8 @@
uint64_t EltIdx = FindElementAndOffset(T, EltOffset, IdxTy);
NewArgs.push_back(ConstantInt::get(IdxTy, EltIdx));
}
+ if (NonConstantIdx)
+ NewArgs.push_back(NonConstantIdx);
Instruction *Val = NewElts[Idx];
if (NewArgs.size() > 1) {
Val = GetElementPtrInst::CreateInBounds(Val, NewArgs, "", GEPI);