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SPV 1.4: Lookup tables: Use variable initializer and NonWritable...

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...when doing a variable lookup on an array of constants.
This commit is contained in:
John Kessenich 2019-02-07 08:04:12 -07:00
parent fbb6bdf046
commit 61a5ce190a
6 changed files with 102 additions and 11 deletions
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23
SPIRV/SpvBuilder.cpp
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@ -1306,11 +1306,13 @@ void Builder::makeDiscard()
}
// Comments in header
Id Builder::createVariable(StorageClass storageClass, Id type, const char* name)
Id Builder::createVariable(StorageClass storageClass, Id type, const char* name, Id initializer)
{
Id pointerType = makePointer(storageClass, type);
Instruction* inst = new Instruction(getUniqueId(), pointerType, OpVariable);
inst->addImmediateOperand(storageClass);
if (initializer != NoResult)
inst->addIdOperand(initializer);
switch (storageClass) {
case StorageClassFunction:
@ -2649,12 +2651,19 @@ Id Builder::accessChainLoad(Decoration precision, Decoration nonUniform, Id resu
if (constant) {
id = createCompositeExtract(accessChain.base, swizzleBase, indexes);
} else {
// make a new function variable for this r-value
Id lValue = createVariable(StorageClassFunction, getTypeId(accessChain.base), "indexable");
// store into it
createStore(accessChain.base, lValue);
Id lValue = NoResult;
if (spvVersion >= Spv_1_4) {
// make a new function variable for this r-value, using an initializer,
// and mark it as NonWritable so that downstream it can be detected as a lookup
// table
lValue = createVariable(StorageClassFunction, getTypeId(accessChain.base), "indexable",
accessChain.base);
addDecoration(lValue, DecorationNonWritable);
} else {
lValue = createVariable(StorageClassFunction, getTypeId(accessChain.base), "indexable");
// store into it
createStore(accessChain.base, lValue);
}
// move base to the new variable
accessChain.base = lValue;
accessChain.isRValue = false;