Masked Load/Store optimization for scalar code
When we have to convert the masked.load, masked.store to scalar code, we generate a chain of conditional basic blocks.
I added optimization for constant mask vector.
Differential Revision: http://reviews.llvm.org/D13855
llvm-svn: 250893
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 922689e..2d260f5 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -1121,35 +1121,68 @@
//
static void ScalarizeMaskedLoad(CallInst *CI) {
Value *Ptr = CI->getArgOperand(0);
- Value *Src0 = CI->getArgOperand(3);
+ Value *Alignment = CI->getArgOperand(1);
Value *Mask = CI->getArgOperand(2);
- VectorType *VecType = dyn_cast<VectorType>(CI->getType());
- Type *EltTy = VecType->getElementType();
+ Value *Src0 = CI->getArgOperand(3);
+ unsigned AlignVal = cast<ConstantInt>(Alignment)->getZExtValue();
+ VectorType *VecType = dyn_cast<VectorType>(CI->getType());
assert(VecType && "Unexpected return type of masked load intrinsic");
+ Type *EltTy = CI->getType()->getVectorElementType();
+
IRBuilder<> Builder(CI->getContext());
Instruction *InsertPt = CI;
BasicBlock *IfBlock = CI->getParent();
BasicBlock *CondBlock = nullptr;
BasicBlock *PrevIfBlock = CI->getParent();
- Builder.SetInsertPoint(InsertPt);
+ Builder.SetInsertPoint(InsertPt);
Builder.SetCurrentDebugLocation(CI->getDebugLoc());
+ // Short-cut if the mask is all-true.
+ bool IsAllOnesMask = isa<Constant>(Mask) &&
+ cast<Constant>(Mask)->isAllOnesValue();
+
+ if (IsAllOnesMask) {
+ Value *NewI = Builder.CreateAlignedLoad(Ptr, AlignVal);
+ CI->replaceAllUsesWith(NewI);
+ CI->eraseFromParent();
+ return;
+ }
+
+ // Adjust alignment for the scalar instruction.
+ AlignVal = std::min(AlignVal, VecType->getScalarSizeInBits()/8);
// Bitcast %addr fron i8* to EltTy*
Type *NewPtrType =
EltTy->getPointerTo(cast<PointerType>(Ptr->getType())->getAddressSpace());
Value *FirstEltPtr = Builder.CreateBitCast(Ptr, NewPtrType);
+ unsigned VectorWidth = VecType->getNumElements();
+
Value *UndefVal = UndefValue::get(VecType);
// The result vector
Value *VResult = UndefVal;
+ if (isa<ConstantVector>(Mask)) {
+ for (unsigned Idx = 0; Idx < VectorWidth; ++Idx) {
+ if (cast<ConstantVector>(Mask)->getOperand(Idx)->isNullValue())
+ continue;
+ Value *Gep =
+ Builder.CreateInBoundsGEP(EltTy, FirstEltPtr, Builder.getInt32(Idx));
+ LoadInst* Load = Builder.CreateAlignedLoad(Gep, AlignVal);
+ VResult = Builder.CreateInsertElement(VResult, Load,
+ Builder.getInt32(Idx));
+ }
+ Value *NewI = Builder.CreateSelect(Mask, VResult, Src0);
+ CI->replaceAllUsesWith(NewI);
+ CI->eraseFromParent();
+ return;
+ }
+
PHINode *Phi = nullptr;
Value *PrevPhi = UndefVal;
- unsigned VectorWidth = VecType->getNumElements();
for (unsigned Idx = 0; Idx < VectorWidth; ++Idx) {
// Fill the "else" block, created in the previous iteration
@@ -1182,7 +1215,7 @@
Value *Gep =
Builder.CreateInBoundsGEP(EltTy, FirstEltPtr, Builder.getInt32(Idx));
- LoadInst* Load = Builder.CreateLoad(Gep, false);
+ LoadInst* Load = Builder.CreateAlignedLoad(Gep, AlignVal);
VResult = Builder.CreateInsertElement(VResult, Load, Builder.getInt32(Idx));
// Create "else" block, fill it in the next iteration
@@ -1233,34 +1266,61 @@
// br label %else2
// . . .
static void ScalarizeMaskedStore(CallInst *CI) {
- Value *Ptr = CI->getArgOperand(1);
Value *Src = CI->getArgOperand(0);
+ Value *Ptr = CI->getArgOperand(1);
+ Value *Alignment = CI->getArgOperand(2);
Value *Mask = CI->getArgOperand(3);
+ unsigned AlignVal = cast<ConstantInt>(Alignment)->getZExtValue();
VectorType *VecType = dyn_cast<VectorType>(Src->getType());
- Type *EltTy = VecType->getElementType();
-
assert(VecType && "Unexpected data type in masked store intrinsic");
+ Type *EltTy = VecType->getElementType();
+
IRBuilder<> Builder(CI->getContext());
Instruction *InsertPt = CI;
BasicBlock *IfBlock = CI->getParent();
Builder.SetInsertPoint(InsertPt);
Builder.SetCurrentDebugLocation(CI->getDebugLoc());
+ // Short-cut if the mask is all-true.
+ bool IsAllOnesMask = isa<Constant>(Mask) &&
+ cast<Constant>(Mask)->isAllOnesValue();
+
+ if (IsAllOnesMask) {
+ Builder.CreateAlignedStore(Src, Ptr, AlignVal);
+ CI->eraseFromParent();
+ return;
+ }
+
+ // Adjust alignment for the scalar instruction.
+ AlignVal = std::max(AlignVal, VecType->getScalarSizeInBits()/8);
// Bitcast %addr fron i8* to EltTy*
Type *NewPtrType =
EltTy->getPointerTo(cast<PointerType>(Ptr->getType())->getAddressSpace());
Value *FirstEltPtr = Builder.CreateBitCast(Ptr, NewPtrType);
-
unsigned VectorWidth = VecType->getNumElements();
+
+ if (isa<ConstantVector>(Mask)) {
+ for (unsigned Idx = 0; Idx < VectorWidth; ++Idx) {
+ if (cast<ConstantVector>(Mask)->getOperand(Idx)->isNullValue())
+ continue;
+ Value *OneElt = Builder.CreateExtractElement(Src, Builder.getInt32(Idx));
+ Value *Gep =
+ Builder.CreateInBoundsGEP(EltTy, FirstEltPtr, Builder.getInt32(Idx));
+ Builder.CreateAlignedStore(OneElt, Gep, AlignVal);
+ }
+ CI->eraseFromParent();
+ return;
+ }
+
for (unsigned Idx = 0; Idx < VectorWidth; ++Idx) {
// Fill the "else" block, created in the previous iteration
//
// %mask_1 = extractelement <16 x i1> %mask, i32 Idx
// %to_store = icmp eq i1 %mask_1, true
- // br i1 %to_load, label %cond.store, label %else
+ // br i1 %to_store, label %cond.store, label %else
//
Value *Predicate = Builder.CreateExtractElement(Mask, Builder.getInt32(Idx));
Value *Cmp = Builder.CreateICmp(ICmpInst::ICMP_EQ, Predicate,
@@ -1279,7 +1339,7 @@
Value *OneElt = Builder.CreateExtractElement(Src, Builder.getInt32(Idx));
Value *Gep =
Builder.CreateInBoundsGEP(EltTy, FirstEltPtr, Builder.getInt32(Idx));
- Builder.CreateStore(OneElt, Gep);
+ Builder.CreateAlignedStore(OneElt, Gep, AlignVal);
// Create "else" block, fill it in the next iteration
BasicBlock *NewIfBlock =