SLPVectorizer: support slp-vectorization of PHINodes between basic blocks

llvm-svn: 184888
This commit is contained in:
Nadav Rotem 2013-06-25 23:04:09 +00:00
parent 71bdbb0101
commit 0794acc1da
2 changed files with 142 additions and 1 deletions

View File

@ -239,6 +239,10 @@ public:
/// NOTICE: The vectorization methods also use this set.
ValueSet MustGather;
/// Contains PHINodes that are being processed. We use this data structure
/// to stop cycles in the graph.
ValueSet VisitedPHIs;
/// Contains a list of values that are used outside the current tree. This
/// set must be reset between runs.
SetVector<Value *> MultiUserVals;
@ -457,13 +461,31 @@ void FuncSLP::getTreeUses_rec(ArrayRef<Value *> VL, unsigned Depth) {
// Mark instructions with multiple users.
for (unsigned i = 0, e = VL.size(); i < e; ++i) {
if (PHINode *PN = dyn_cast<PHINode>(VL[i])) {
unsigned NumUses = 0;
// Check that PHINodes have only one external (non-self) use.
for (Value::use_iterator U = VL[i]->use_begin(), UE = VL[i]->use_end();
U != UE; ++U) {
// Don't count self uses.
if (*U == PN)
continue;
NumUses++;
}
if (NumUses > 1) {
DEBUG(dbgs() << "SLP: Adding PHI to MultiUserVals "
"because it has " << NumUses << " users:" << *PN << " \n");
MultiUserVals.insert(PN);
}
continue;
}
Instruction *I = dyn_cast<Instruction>(VL[i]);
// Remember to check if all of the users of this instruction are vectorized
// within our tree. At depth zero we have no local users, only external
// users that we don't care about.
if (Depth && I && I->getNumUses() > 1) {
DEBUG(dbgs() << "SLP: Adding to MultiUserVals "
"because it has multiple users:" << *I << " \n");
"because it has " << I->getNumUses() << " users:" << *I << " \n");
MultiUserVals.insert(I);
}
}
@ -483,6 +505,24 @@ void FuncSLP::getTreeUses_rec(ArrayRef<Value *> VL, unsigned Depth) {
return MustGather.insert(VL.begin(), VL.end());
switch (Opcode) {
case Instruction::PHI: {
PHINode *PH = dyn_cast<PHINode>(VL0);
// Stop self cycles.
if (VisitedPHIs.count(PH))
return;
VisitedPHIs.insert(PH);
for (unsigned i = 0, e = PH->getNumIncomingValues(); i < e; ++i) {
ValueList Operands;
// Prepare the operand vector.
for (unsigned j = 0; j < VL.size(); ++j)
Operands.push_back(cast<PHINode>(VL[j])->getIncomingValue(i));
getTreeUses_rec(Operands, Depth + 1);
}
return;
}
case Instruction::ExtractElement: {
VectorType *VecTy = VectorType::get(VL[0]->getType(), VL.size());
// No need to follow ExtractElements that are going to be optimized away.
@ -640,6 +680,35 @@ int FuncSLP::getTreeCost_rec(ArrayRef<Value *> VL, unsigned Depth) {
Instruction *VL0 = cast<Instruction>(VL[0]);
switch (Opcode) {
case Instruction::PHI: {
PHINode *PH = dyn_cast<PHINode>(VL0);
// Stop self cycles.
if (VisitedPHIs.count(PH))
return 0;
VisitedPHIs.insert(PH);
int TotalCost = 0;
// Calculate the cost of all of the operands.
for (unsigned i = 0, e = PH->getNumIncomingValues(); i < e; ++i) {
ValueList Operands;
// Prepare the operand vector.
for (unsigned j = 0; j < VL.size(); ++j)
Operands.push_back(cast<PHINode>(VL[j])->getIncomingValue(i));
int Cost = getTreeCost_rec(Operands, Depth + 1);
if (Cost == MAX_COST)
return MAX_COST;
TotalCost += TotalCost;
}
if (TotalCost > GatherCost) {
MustGather.insert(VL.begin(), VL.end());
return GatherCost;
}
return TotalCost;
}
case Instruction::ExtractElement: {
if (CanReuseExtract(VL, VL.size(), VecTy))
return 0;
@ -806,6 +875,7 @@ int FuncSLP::getTreeCost(ArrayRef<Value *> VL) {
LaneMap.clear();
MultiUserVals.clear();
MustGather.clear();
VisitedPHIs.clear();
if (!getSameBlock(VL))
return MAX_COST;
@ -990,6 +1060,30 @@ Value *FuncSLP::vectorizeTree_rec(ArrayRef<Value *> VL) {
assert(Opcode == getSameOpcode(VL) && "Invalid opcode");
switch (Opcode) {
case Instruction::PHI: {
PHINode *PH = dyn_cast<PHINode>(VL0);
Builder.SetInsertPoint(PH->getParent()->getFirstInsertionPt());
PHINode *NewPhi = Builder.CreatePHI(VecTy, PH->getNumIncomingValues());
VectorizedValues[VL0] = NewPhi;
for (unsigned i = 0, e = PH->getNumIncomingValues(); i < e; ++i) {
ValueList Operands;
BasicBlock *IBB = PH->getIncomingBlock(i);
// Prepare the operand vector.
for (unsigned j = 0; j < VL.size(); ++j)
Operands.push_back(cast<PHINode>(VL[j])->getIncomingValueForBlock(IBB));
Builder.SetInsertPoint(IBB->getTerminator());
Value *Vec = vectorizeTree_rec(Operands);
NewPhi->addIncoming(Vec, IBB);
}
assert(NewPhi->getNumIncomingValues() == PH->getNumIncomingValues() &&
"Invalid number of incoming values");
return NewPhi;
}
case Instruction::ExtractElement: {
if (CanReuseExtract(VL, VL.size(), VecTy))
return VL0->getOperand(0);
@ -1150,6 +1244,7 @@ Value *FuncSLP::vectorizeTree(ArrayRef<Value *> VL) {
BlocksNumbers[it].forget();
// Clear the state.
MustGather.clear();
VisitedPHIs.clear();
VectorizedValues.clear();
MemBarrierIgnoreList.clear();
return V;

View File

@ -0,0 +1,46 @@
; RUN: opt < %s -basicaa -slp-vectorizer -dce -S -mtriple=i386-apple-macosx10.8.0 -mcpu=corei7-avx | FileCheck %s
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32-S128"
target triple = "i386-apple-macosx10.9.0"
;int foo(double *A, int k) {
; double A0;
; double A1;
; if (k) {
; A0 = 3;
; A1 = 5;
; } else {
; A0 = A[10];
; A1 = A[11];
; }
; A[0] = A0;
; A[1] = A1;
;}
;CHECK: i32 @foo
;CHECK: load <2 x double>
;CHECK: phi <2 x double>
;CHECK: store <2 x double>
;CHECK: ret i32 undef
define i32 @foo(double* nocapture %A, i32 %k) {
entry:
%tobool = icmp eq i32 %k, 0
br i1 %tobool, label %if.else, label %if.end
if.else: ; preds = %entry
%arrayidx = getelementptr inbounds double* %A, i64 10
%0 = load double* %arrayidx, align 8
%arrayidx1 = getelementptr inbounds double* %A, i64 11
%1 = load double* %arrayidx1, align 8
br label %if.end
if.end: ; preds = %entry, %if.else
%A0.0 = phi double [ %0, %if.else ], [ 3.000000e+00, %entry ]
%A1.0 = phi double [ %1, %if.else ], [ 5.000000e+00, %entry ]
store double %A0.0, double* %A, align 8
%arrayidx3 = getelementptr inbounds double* %A, i64 1
store double %A1.0, double* %arrayidx3, align 8
ret i32 undef
}