aaron/ispc
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Broadcast implementation as InsertElement+Shuffle and related improvements

Browse Source
This commit is contained in:
Dmitry Babokin
2013-04-10 02:18:24 +04:00
parent 603abf70dc
commit 5898532605
6 changed files with 153 additions and 56 deletions
Download Patch File Download Diff File Expand all files Collapse all files

102
llvmutil.cpp
View File

@@ -601,44 +601,74 @@ lGetIntValue(llvm::Value *offset) {
void
LLVMFlattenInsertChain(llvm::InsertElementInst *ie, int vectorWidth,
LLVMFlattenInsertChain(llvm::Value *inst, int vectorWidth,
llvm::Value **elements) {
for (int i = 0; i < vectorWidth; ++i)
for (int i = 0; i < vectorWidth; ++i) {
elements[i] = NULL;
}
while (ie != NULL) {
int64_t iOffset = lGetIntValue(ie->getOperand(2));
Assert(iOffset >= 0 && iOffset < vectorWidth);
Assert(elements[iOffset] == NULL);
// Catch a pattern of InsertElement chain.
if (llvm::InsertElementInst *ie =
llvm::dyn_cast<llvm::InsertElementInst>(inst)) {
while (ie != NULL) {
int64_t iOffset = lGetIntValue(ie->getOperand(2));
Assert(iOffset >= 0 && iOffset < vectorWidth);
Assert(elements[iOffset] == NULL);
// Get the scalar value from this insert
elements[iOffset] = ie->getOperand(1);
// Get the scalar value from this insert
elements[iOffset] = ie->getOperand(1);
// Do we have another insert?
llvm::Value *insertBase = ie->getOperand(0);
ie = llvm::dyn_cast<llvm::InsertElementInst>(insertBase);
if (ie == NULL) {
if (llvm::isa<llvm::UndefValue>(insertBase))
return;
// Do we have another insert?
llvm::Value *insertBase = ie->getOperand(0);
ie = llvm::dyn_cast<llvm::InsertElementInst>(insertBase);
if (ie == NULL) {
if (llvm::isa<llvm::UndefValue>(insertBase)) {
return;
}
// Get the value out of a constant vector if that's what we
// have
llvm::ConstantVector *cv =
llvm::dyn_cast<llvm::ConstantVector>(insertBase);
// Get the value out of a constant vector if that's what we
// have
llvm::ConstantVector *cv =
llvm::dyn_cast<llvm::ConstantVector>(insertBase);
// FIXME: this assert is a little questionable; we probably
// shouldn't fail in this case but should just return an
// incomplete result. But there aren't currently any known
// cases where we have anything other than an undef value or a
// constant vector at the base, so if that ever does happen,
// it'd be nice to know what happend so that perhaps we can
// handle it.
// FIXME: Also, should we handle ConstantDataVectors with
// LLVM3.1? What about ConstantAggregateZero values??
Assert(cv != NULL);
// FIXME: this assert is a little questionable; we probably
// shouldn't fail in this case but should just return an
// incomplete result. But there aren't currently any known
// cases where we have anything other than an undef value or a
// constant vector at the base, so if that ever does happen,
// it'd be nice to know what happend so that perhaps we can
// handle it.
// FIXME: Also, should we handle ConstantDataVectors with
// LLVM3.1? What about ConstantAggregateZero values??
Assert(cv != NULL);
Assert(iOffset < (int)cv->getNumOperands());
elements[iOffset] = cv->getOperand((int32_t)iOffset);
Assert(iOffset < (int)cv->getNumOperands());
elements[iOffset] = cv->getOperand((int32_t)iOffset);
}
}
}
// Catch a pattern of broadcast implemented as InsertElement + Shuffle:
// %broadcast_init.0 = insertelement <4 x i32> undef, i32 %val, i32 0
// %broadcast.1 = shufflevector <4 x i32> %smear.0, <4 x i32> undef,
// <4 x i32> zeroinitializer
else if (llvm::ShuffleVectorInst *shuf =
llvm::dyn_cast<llvm::ShuffleVectorInst>(inst)) {
llvm::Value *indices = shuf->getOperand(2);
if (llvm::isa<llvm::ConstantAggregateZero>(indices)) {
llvm::Value *op = shuf->getOperand(0);
llvm::InsertElementInst *ie = llvm::dyn_cast<llvm::InsertElementInst>(op);
if (ie != NULL &&
llvm::isa<llvm::UndefValue>(ie->getOperand(0))) {
llvm::ConstantInt *ci =
llvm::dyn_cast<llvm::ConstantInt>(ie->getOperand(2));
if (ci->isZero()) {
for (int i = 0; i < vectorWidth; ++i) {
elements[i] = ie->getOperand(1);
}
return;
}
}
}
}
}
@@ -694,10 +724,10 @@ lIsExactMultiple(llvm::Value *val, int baseValue, int vectorLength,
else
Assert(LLVMVectorValuesAllEqual(val));
llvm::InsertElementInst *ie = llvm::dyn_cast<llvm::InsertElementInst>(val);
if (ie != NULL) {
if (llvm::isa<llvm::InsertElementInst>(val) ||
llvm::isa<llvm::ShuffleVectorInst>(val)) {
llvm::Value *elts[ISPC_MAX_NVEC];
LLVMFlattenInsertChain(ie, g->target->getVectorWidth(), elts);
LLVMFlattenInsertChain(val, g->target->getVectorWidth(), elts);
// We just need to check the scalar first value, since we know that
// all elements are equal
return lIsExactMultiple(elts[0], baseValue, vectorLength,
@@ -1440,10 +1470,10 @@ lExtractFirstVectorElement(llvm::Value *v,
// If we have a chain of insertelement instructions, then we can just
// flatten them out and grab the value for the first one.
llvm::InsertElementInst *ie = llvm::dyn_cast<llvm::InsertElementInst>(v);
if (ie != NULL) {
if (llvm::isa<llvm::InsertElementInst>(v) ||
llvm::isa<llvm::ShuffleVectorInst>(v)) {
llvm::Value *elements[ISPC_MAX_NVEC];
LLVMFlattenInsertChain(ie, vt->getNumElements(), elements);
LLVMFlattenInsertChain(v, vt->getNumElements(), elements);
return elements[0];
}