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Fix big-endian handling of integer-to-vector bitcasts in InstCombine

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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
This commit is contained in:
Richard Sandiford 2013-08-12 07:26:09 +00:00
parent 5e4b95b3fe
commit 23331c30ae
2 changed files with 73 additions and 20 deletions
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52
lib/Transforms/InstCombine/InstCombineCasts.cpp
View File

@ -1488,12 +1488,17 @@ static unsigned getTypeSizeIndex(unsigned Value, Type *Ty) {
/// 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 @@ static bool CollectInsertionElements(Value *V, unsigned ElementIndex,
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 @@ static bool CollectInsertionElements(Value *V, unsigned ElementIndex,
// 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 @@ static bool CollectInsertionElements(Value *V, unsigned ElementIndex,
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 @@ static bool CollectInsertionElements(Value *V, unsigned ElementIndex,
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 @@ static bool CollectInsertionElements(Value *V, unsigned ElementIndex,
/// 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

41
test/Transforms/InstCombine/bitcast-bigendian.ll
View File

@ -48,3 +48,44 @@ define float @test3(<2 x float> %A, <2 x i64> %B) {
; CHECK-NEXT: ret float %add
}
define <2 x i32> @test4(i32 %A, i32 %B){
%tmp38 = zext i32 %A to i64
%tmp32 = zext i32 %B to i64
%tmp33 = shl i64 %tmp32, 32
%ins35 = or i64 %tmp33, %tmp38
%tmp43 = bitcast i64 %ins35 to <2 x i32>
ret <2 x i32> %tmp43
; CHECK-LABEL: @test4(
; CHECK-NEXT: insertelement <2 x i32> undef, i32 %B, i32 0
; CHECK-NEXT: insertelement <2 x i32> {{.*}}, i32 %A, i32 1
; CHECK-NEXT: ret <2 x i32>
}
define <2 x float> @test5(float %A, float %B) {
%tmp37 = bitcast float %A to i32
%tmp38 = zext i32 %tmp37 to i64
%tmp31 = bitcast float %B to i32
%tmp32 = zext i32 %tmp31 to i64
%tmp33 = shl i64 %tmp32, 32
%ins35 = or i64 %tmp33, %tmp38
%tmp43 = bitcast i64 %ins35 to <2 x float>
ret <2 x float> %tmp43
; CHECK-LABEL: @test5(
; CHECK-NEXT: insertelement <2 x float> undef, float %B, i32 0
; CHECK-NEXT: insertelement <2 x float> {{.*}}, float %A, i32 1
; CHECK-NEXT: ret <2 x float>
}
define <2 x float> @test6(float %A){
%tmp23 = bitcast float %A to i32 ; <i32> [#uses=1]
%tmp24 = zext i32 %tmp23 to i64 ; <i64> [#uses=1]
%tmp25 = shl i64 %tmp24, 32 ; <i64> [#uses=1]
%mask20 = or i64 %tmp25, 1109917696 ; <i64> [#uses=1]
%tmp35 = bitcast i64 %mask20 to <2 x float> ; <<2 x float>> [#uses=1]
ret <2 x float> %tmp35
; CHECK-LABEL: @test6(
; CHECK-NEXT: insertelement <2 x float> undef, float %A, i32 0
; CHECK-NEXT: insertelement <2 x float> {{.*}}, float 4.200000e+01, i32 1
; CHECK: ret
}