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Define dereferencing varying pointer to uniform struct with 'bound uniform' member.

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This commit is contained in:
Vsevolod Livinskiy
2016-02-05 14:49:42 +03:00
parent 243d6c2625
commit 0ef3d3b429
3 changed files with 76 additions and 4 deletions
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40
ctx.cpp
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@@ -2805,7 +2805,8 @@ FunctionEmitContext::loadUniformFromSOA(llvm::Value *ptr, llvm::Value *mask,
llvm::Value *
FunctionEmitContext::LoadInst(llvm::Value *ptr, llvm::Value *mask,
const Type *ptrRefType, const char *name) {
const Type *ptrRefType, const char *name,
bool one_elem) {
if (ptr == NULL) {
AssertPos(currentPos, m->errorCount > 0);
return NULL;
@@ -2861,7 +2862,33 @@ FunctionEmitContext::LoadInst(llvm::Value *ptr, llvm::Value *mask,
else {
// Otherwise we should have a varying ptr and it's time for a
// gather.
return gather(ptr, ptrType, GetFullMask(), name);
llvm::Value *gather_result = gather(ptr, ptrType, GetFullMask(), name);
if (!one_elem)
return gather_result;
// It is a kludge. When we dereference varying pointer to uniform struct
// with "bound uniform" member, we should return first unmasked member.
Warning(currentPos, "Dereferencing varying pointer to uniform struct with 'bound uniform' member,\n"
" only one value will survive. Possible loss of data.");
// Call the target-dependent movmsk function to turn the vector mask
// into an i64 value
std::vector<Symbol *> mm;
m->symbolTable->LookupFunction("__movmsk", &mm);
if (g->target->getMaskBitCount() == 1)
AssertPos(currentPos, mm.size() == 1);
else
// There should be one with signed int signature, one unsigned int.
AssertPos(currentPos, mm.size() == 2);
// We can actually call either one, since both are i32s as far as
// LLVM's type system is concerned...
llvm::Function *fmm = mm[0]->function;
llvm::Value *int_mask = CallInst(fmm, NULL, mask, LLVMGetName(mask, "_movmsk"));
std::vector<Symbol *> lz;
m->symbolTable->LookupFunction("__count_trailing_zeros_i64", &lz);
llvm::Function *flz = lz[0]->function;
llvm::Value *elem_idx = CallInst(flz, NULL, int_mask, LLVMGetName(mask, "_clz"));
llvm::Value *elem = llvm::ExtractElementInst::Create(gather_result, elem_idx, LLVMGetName(gather_result, "_umasked_elem"), bblock);
return elem;
}
}
@@ -2882,6 +2909,9 @@ FunctionEmitContext::gather(llvm::Value *ptr, const PointerType *ptrType,
// result.
llvm::Value *retValue = llvm::UndefValue::get(llvmReturnType);
const CollectionType *returnCollectionType =
CastType<CollectionType>(returnType->GetBaseType());
for (int i = 0; i < collectionType->GetElementCount(); ++i) {
const PointerType *eltPtrType;
llvm::Value *eltPtr =
@@ -2889,8 +2919,12 @@ FunctionEmitContext::gather(llvm::Value *ptr, const PointerType *ptrType,
eltPtr = addVaryingOffsetsIfNeeded(eltPtr, eltPtrType);
// It is a kludge. When we dereference varying pointer to uniform struct
// with "bound uniform" member, we should return first unmasked member.
int need_one_elem = CastType<StructType>(ptrType->GetBaseType()) &&
returnCollectionType->GetElementType(i)->IsUniformType();
// This in turn will be another gather
llvm::Value *eltValues = LoadInst(eltPtr, mask, eltPtrType, name);
llvm::Value *eltValues = LoadInst(eltPtr, mask, eltPtrType, name, need_one_elem);
retValue = InsertInst(retValue, eltValues, i, "set_value");
}