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InstSimplify: Make shift, select and GEP simplifications vector-aware.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200016 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Benjamin Kramer 2014-01-24 17:09:53 +00:00
parent c55979b28d
commit c166623dcd
4 changed files with 114 additions and 19 deletions
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59
lib/Analysis/InstructionSimplify.cpp
View File

@ -1288,6 +1288,33 @@ Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, const DataLayout *TD,
return ::SimplifyFRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
}
/// isUndefShift - Returns true if a shift by \c Amount always yields undef.
static bool isUndefShift(Value *Amount) {
Constant *C = dyn_cast<Constant>(Amount);
if (!C)
return false;
// X shift by undef -> undef because it may shift by the bitwidth.
if (isa<UndefValue>(C))
return true;
// Shifting by the bitwidth or more is undefined.
if (ConstantInt *CI = dyn_cast<ConstantInt>(C))
if (CI->getValue().getLimitedValue() >=
CI->getType()->getScalarSizeInBits())
return true;
// If all lanes of a vector shift are undefined the whole shift is.
if (isa<ConstantVector>(C) || isa<ConstantDataVector>(C)) {
for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E; ++I)
if (!isUndefShift(C->getAggregateElement(I)))
return false;
return true;
}
return false;
}
/// SimplifyShift - Given operands for an Shl, LShr or AShr, see if we can
/// fold the result. If not, this returns null.
static Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1,
@ -1307,15 +1334,9 @@ static Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1,
if (match(Op1, m_Zero()))
return Op0;
// X shift by undef -> undef because it may shift by the bitwidth.
if (match(Op1, m_Undef()))
return Op1;
// Shifting by the bitwidth or more is undefined.
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1))
if (CI->getValue().getLimitedValue() >=
Op0->getType()->getScalarSizeInBits())
return UndefValue::get(Op0->getType());
// Fold undefined shifts.
if (isUndefShift(Op1))
return UndefValue::get(Op0->getType());
// If the operation is with the result of a select instruction, check whether
// operating on either branch of the select always yields the same value.
@ -2699,8 +2720,12 @@ static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
unsigned MaxRecurse) {
// select true, X, Y -> X
// select false, X, Y -> Y
if (ConstantInt *CB = dyn_cast<ConstantInt>(CondVal))
return CB->getZExtValue() ? TrueVal : FalseVal;
if (Constant *CB = dyn_cast<Constant>(CondVal)) {
if (CB->isAllOnesValue())
return TrueVal;
if (CB->isNullValue())
return FalseVal;
}
// select C, X, X -> X
if (TrueVal == FalseVal)
@ -2731,10 +2756,7 @@ Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
/// fold the result. If not, this returns null.
static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) {
// The type of the GEP pointer operand.
PointerType *PtrTy = dyn_cast<PointerType>(Ops[0]->getType());
// The GEP pointer operand is not a pointer, it's a vector of pointers.
if (!PtrTy)
return 0;
PointerType *PtrTy = cast<PointerType>(Ops[0]->getType()->getScalarType());
// getelementptr P -> P.
if (Ops.size() == 1)
@ -2744,14 +2766,15 @@ static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) {
// Compute the (pointer) type returned by the GEP instruction.
Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
Type *GEPTy = PointerType::get(LastType, PtrTy->getAddressSpace());
if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
GEPTy = VectorType::get(GEPTy, VT->getNumElements());
return UndefValue::get(GEPTy);
}
if (Ops.size() == 2) {
// getelementptr P, 0 -> P.
if (ConstantInt *C = dyn_cast<ConstantInt>(Ops[1]))
if (C->isZero())
return Ops[0];
if (match(Ops[1], m_Zero()))
return Ops[0];
// getelementptr P, N -> P if P points to a type of zero size.
if (Q.TD) {
Type *Ty = PtrTy->getElementType();

18
test/Transforms/InstSimplify/compare.ll
View File

@ -739,3 +739,21 @@ define i1 @non_inbounds_gep_compare2(i64* %a) {
ret i1 %cmp
; CHECK-NEXT: ret i1 true
}
define <4 x i8> @vectorselectfold(<4 x i8> %a, <4 x i8> %b) {
%false = icmp ne <4 x i8> zeroinitializer, zeroinitializer
%sel = select <4 x i1> %false, <4 x i8> %a, <4 x i8> %b
ret <4 x i8> %sel
; CHECK-LABEL: @vectorselectfold
; CHECK-NEXT: ret <4 x i8> %b
}
define <4 x i8> @vectorselectfold2(<4 x i8> %a, <4 x i8> %b) {
%true = icmp eq <4 x i8> zeroinitializer, zeroinitializer
%sel = select <4 x i1> %true, <4 x i8> %a, <4 x i8> %b
ret <4 x i8> %sel
; CHECK-LABEL: @vectorselectfold
; CHECK-NEXT: ret <4 x i8> %a
}

7
test/Transforms/InstSimplify/undef.ll
View File

@ -153,3 +153,10 @@ define i64 @test18(i64 %a) {
%r = call i64 (i64)* undef(i64 %a)
ret i64 %r
}
; CHECK-LABEL: @test19
; CHECK: ret <4 x i8> undef
define <4 x i8> @test19(<4 x i8> %a) {
%b = shl <4 x i8> %a, <i8 8, i8 9, i8 undef, i8 -1>
ret <4 x i8> %b
}

49
test/Transforms/InstSimplify/vector_gep.ll
View File

@ -1,4 +1,7 @@
;RUN: opt -instsimplify -disable-output < %s
; RUN: opt -S -instsimplify < %s | FileCheck %s
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
declare void @helper(<2 x i8*>)
define void @test(<2 x i8*> %a) {
%A = getelementptr <2 x i8*> %a, <2 x i32> <i32 0, i32 0>
@ -6,3 +9,47 @@ define void @test(<2 x i8*> %a) {
ret void
}
define <4 x i8*> @test1(<4 x i8*> %a) {
%gep = getelementptr <4 x i8*> %a, <4 x i32> zeroinitializer
ret <4 x i8*> %gep
; CHECK-LABEL: @test1
; CHECK-NEXT: ret <4 x i8*> %a
}
define <4 x i8*> @test2(<4 x i8*> %a) {
%gep = getelementptr <4 x i8*> %a
ret <4 x i8*> %gep
; CHECK-LABEL: @test2
; CHECK-NEXT: ret <4 x i8*> %a
}
%struct = type { double, float }
define <4 x float*> @test3() {
%gep = getelementptr <4 x %struct*> undef, <4 x i32> <i32 1, i32 1, i32 1, i32 1>, <4 x i32> <i32 1, i32 1, i32 1, i32 1>
ret <4 x float*> %gep
; CHECK-LABEL: @test3
; CHECK-NEXT: ret <4 x float*> undef
}
%struct.empty = type { }
define <4 x %struct.empty*> @test4(<4 x %struct.empty*> %a) {
%gep = getelementptr <4 x %struct.empty*> %a, <4 x i32> <i32 1, i32 1, i32 1, i32 1>
ret <4 x %struct.empty*> %gep
; CHECK-LABEL: @test4
; CHECK-NEXT: ret <4 x %struct.empty*> %a
}
define <4 x i8*> @test5() {
%c = inttoptr <4 x i64> <i64 1, i64 2, i64 3, i64 4> to <4 x i8*>
%gep = getelementptr <4 x i8*> %c, <4 x i32> <i32 1, i32 1, i32 1, i32 1>
ret <4 x i8*> %gep
; CHECK-LABEL: @test5
; CHECK-NEXT: ret <4 x i8*> getelementptr (<4 x i8*> <i8* inttoptr (i64 1 to i8*), i8* inttoptr (i64 2 to i8*), i8* inttoptr (i64 3 to i8*), i8* inttoptr (i64 4 to i8*)>, <4 x i32> <i32 1, i32 1, i32 1, i32 1>)
}