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optimize "integer extraction out of the middle of a vector" as produced

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by SRoA.  This is part of rdar://7892780, but needs another xform to
expose this.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112232 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2010-08-26 22:14:59 +00:00
parent 1ab3f16f06
commit 26dbe7ec18
2 changed files with 60 additions and 13 deletions
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48
lib/Transforms/InstCombine/InstCombineCasts.cpp
View File

@ -1337,31 +1337,53 @@ static Instruction *OptimizeVectorResize(Value *InVal, const VectorType *DestTy,
/// OptimizeIntToFloatBitCast - See if we can optimize an integer->float/double
/// bitcast. The various long double bitcasts can't get in here.
static Instruction *OptimizeIntToFloatBitCast(BitCastInst &CI,InstCombiner &IC) {
static Instruction *OptimizeIntToFloatBitCast(BitCastInst &CI,InstCombiner &IC){
Value *Src = CI.getOperand(0);
const Type *DestTy = CI.getType();
// If this is a bitcast from int to float, check to see if the int is an
// extraction from a vector.
Value *VecInput = 0;
// bitcast(trunc(bitcast(somevector)))
if (match(Src, m_Trunc(m_BitCast(m_Value(VecInput)))) &&
isa<VectorType>(VecInput->getType())) {
const VectorType *VecTy = cast<VectorType>(VecInput->getType());
const Type *DestTy = CI.getType();
unsigned DestWidth = DestTy->getPrimitiveSizeInBits();
if (VecTy->getPrimitiveSizeInBits() % DestWidth == 0) {
// If the element type of the vector doesn't match the result type,
// bitcast it to be a vector type we can extract from.
if (VecTy->getElementType() != DestTy) {
VecTy = VectorType::get(DestTy,
VecTy->getPrimitiveSizeInBits() / DestWidth);
VecInput = IC.Builder->CreateBitCast(VecInput, VecTy);
}
// If the element type of the vector doesn't match the result type, but the
// vector type's size is a multiple of the result type, bitcast it to be a
// vector type we can extract from.
if (VecTy->getElementType() != DestTy &&
VecTy->getPrimitiveSizeInBits() % DestTy->getPrimitiveSizeInBits()==0) {
VecTy = VectorType::get(DestTy,
VecTy->getPrimitiveSizeInBits() / DestTy->getPrimitiveSizeInBits());
VecInput = IC.Builder->CreateBitCast(VecInput, VecTy);
}
if (VecTy->getElementType() == DestTy)
return ExtractElementInst::Create(VecInput, IC.Builder->getInt32(0));
}
}
// bitcast(trunc(lshr(bitcast(somevector), cst))
ConstantInt *ShAmt = 0;
if (match(Src, m_Trunc(m_LShr(m_BitCast(m_Value(VecInput)),
m_ConstantInt(ShAmt)))) &&
isa<VectorType>(VecInput->getType())) {
const VectorType *VecTy = cast<VectorType>(VecInput->getType());
unsigned DestWidth = DestTy->getPrimitiveSizeInBits();
if (VecTy->getPrimitiveSizeInBits() % DestWidth == 0 &&
ShAmt->getZExtValue() % DestWidth == 0) {
// If the element type of the vector doesn't match the result type,
// bitcast it to be a vector type we can extract from.
if (VecTy->getElementType() != DestTy) {
VecTy = VectorType::get(DestTy,
VecTy->getPrimitiveSizeInBits() / DestWidth);
VecInput = IC.Builder->CreateBitCast(VecInput, VecTy);
}
unsigned Elt = ShAmt->getZExtValue() / DestWidth;
return ExtractElementInst::Create(VecInput, IC.Builder->getInt32(Elt));
}
}
return 0;
}

25
test/Transforms/InstCombine/bitcast.ll
View File

@ -35,3 +35,28 @@ define float @test2(<2 x float> %A, <2 x i32> %B) {
; CHECK-NEXT: %add = fadd float %tmp24, %tmp4
; CHECK-NEXT: ret float %add
}
; Optimize bitcasts that are extracting other elements of a vector. This
; happens because of SRoA.
; rdar://7892780
define float @test3(<2 x float> %A, <2 x i64> %B) {
%tmp28 = bitcast <2 x float> %A to i64
%tmp29 = lshr i64 %tmp28, 32
%tmp23 = trunc i64 %tmp29 to i32
%tmp24 = bitcast i32 %tmp23 to float
%tmp = bitcast <2 x i64> %B to i128
%tmp1 = lshr i128 %tmp, 64
%tmp2 = trunc i128 %tmp1 to i32
%tmp4 = bitcast i32 %tmp2 to float
%add = fadd float %tmp24, %tmp4
ret float %add
; CHECK: @test3
; CHECK-NEXT: %tmp24 = extractelement <2 x float> %A, i32 1
; CHECK-NEXT: bitcast <2 x i64> %B to <4 x float>
; CHECK-NEXT: %tmp4 = extractelement <4 x float> {{.*}}, i32 2
; CHECK-NEXT: %add = fadd float %tmp24, %tmp4
; CHECK-NEXT: ret float %add
}