Fix big-endian handling of integer-to-vector bitcasts in InstCombine
These functions used to assume that the lsb of an integer corresponds
to vector element 0, whereas for big-endian it's the other way around:
the msb is in the first element and the lsb is in the last element.
Fixes MultiSource/Benchmarks/mediabench/gsm/toast for z.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188155 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/InstCombine/InstCombineCasts.cpp b/lib/Transforms/InstCombine/InstCombineCasts.cpp
index 361acdd..e2f64d7 100644
--- a/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -1488,12 +1488,17 @@
/// insertions into the vector. See the example in the comment for
/// OptimizeIntegerToVectorInsertions for the pattern this handles.
/// The type of V is always a non-zero multiple of VecEltTy's size.
+/// Shift is the number of bits between the lsb of V and the lsb of
+/// the vector.
///
/// This returns false if the pattern can't be matched or true if it can,
/// filling in Elements with the elements found here.
-static bool CollectInsertionElements(Value *V, unsigned ElementIndex,
+static bool CollectInsertionElements(Value *V, unsigned Shift,
SmallVectorImpl<Value*> &Elements,
- Type *VecEltTy) {
+ Type *VecEltTy, InstCombiner &IC) {
+ assert(isMultipleOfTypeSize(Shift, VecEltTy) &&
+ "Shift should be a multiple of the element type size");
+
// Undef values never contribute useful bits to the result.
if (isa<UndefValue>(V)) return true;
@@ -1505,8 +1510,12 @@
if (C->isNullValue())
return true;
+ unsigned ElementIndex = getTypeSizeIndex(Shift, VecEltTy);
+ if (IC.getDataLayout()->isBigEndian())
+ ElementIndex = Elements.size() - ElementIndex - 1;
+
// Fail if multiple elements are inserted into this slot.
- if (ElementIndex >= Elements.size() || Elements[ElementIndex] != 0)
+ if (Elements[ElementIndex] != 0)
return false;
Elements[ElementIndex] = V;
@@ -1522,7 +1531,7 @@
// it to the right type so it gets properly inserted.
if (NumElts == 1)
return CollectInsertionElements(ConstantExpr::getBitCast(C, VecEltTy),
- ElementIndex, Elements, VecEltTy);
+ Shift, Elements, VecEltTy, IC);
// Okay, this is a constant that covers multiple elements. Slice it up into
// pieces and insert each element-sized piece into the vector.
@@ -1533,10 +1542,11 @@
Type *ElementIntTy = IntegerType::get(C->getContext(), ElementSize);
for (unsigned i = 0; i != NumElts; ++i) {
+ unsigned ShiftI = Shift+i*ElementSize;
Constant *Piece = ConstantExpr::getLShr(C, ConstantInt::get(C->getType(),
- i*ElementSize));
+ ShiftI));
Piece = ConstantExpr::getTrunc(Piece, ElementIntTy);
- if (!CollectInsertionElements(Piece, ElementIndex+i, Elements, VecEltTy))
+ if (!CollectInsertionElements(Piece, ShiftI, Elements, VecEltTy, IC))
return false;
}
return true;
@@ -1549,29 +1559,28 @@
switch (I->getOpcode()) {
default: return false; // Unhandled case.
case Instruction::BitCast:
- return CollectInsertionElements(I->getOperand(0), ElementIndex,
- Elements, VecEltTy);
+ return CollectInsertionElements(I->getOperand(0), Shift,
+ Elements, VecEltTy, IC);
case Instruction::ZExt:
if (!isMultipleOfTypeSize(
I->getOperand(0)->getType()->getPrimitiveSizeInBits(),
VecEltTy))
return false;
- return CollectInsertionElements(I->getOperand(0), ElementIndex,
- Elements, VecEltTy);
+ return CollectInsertionElements(I->getOperand(0), Shift,
+ Elements, VecEltTy, IC);
case Instruction::Or:
- return CollectInsertionElements(I->getOperand(0), ElementIndex,
- Elements, VecEltTy) &&
- CollectInsertionElements(I->getOperand(1), ElementIndex,
- Elements, VecEltTy);
+ return CollectInsertionElements(I->getOperand(0), Shift,
+ Elements, VecEltTy, IC) &&
+ CollectInsertionElements(I->getOperand(1), Shift,
+ Elements, VecEltTy, IC);
case Instruction::Shl: {
// Must be shifting by a constant that is a multiple of the element size.
ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1));
if (CI == 0) return false;
- if (!isMultipleOfTypeSize(CI->getZExtValue(), VecEltTy)) return false;
- unsigned IndexShift = getTypeSizeIndex(CI->getZExtValue(), VecEltTy);
-
- return CollectInsertionElements(I->getOperand(0), ElementIndex+IndexShift,
- Elements, VecEltTy);
+ Shift += CI->getZExtValue();
+ if (!isMultipleOfTypeSize(Shift, VecEltTy)) return false;
+ return CollectInsertionElements(I->getOperand(0), Shift,
+ Elements, VecEltTy, IC);
}
}
@@ -1594,12 +1603,15 @@
/// Into two insertelements that do "buildvector{%inc, %inc5}".
static Value *OptimizeIntegerToVectorInsertions(BitCastInst &CI,
InstCombiner &IC) {
+ // We need to know the target byte order to perform this optimization.
+ if (!IC.getDataLayout()) return 0;
+
VectorType *DestVecTy = cast<VectorType>(CI.getType());
Value *IntInput = CI.getOperand(0);
SmallVector<Value*, 8> Elements(DestVecTy->getNumElements());
if (!CollectInsertionElements(IntInput, 0, Elements,
- DestVecTy->getElementType()))
+ DestVecTy->getElementType(), IC))
return 0;
// If we succeeded, we know that all of the element are specified by Elements