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spv::Builder::Loop constructor inits all members.

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After construction, the Loop is effectively const.

This perturbs the IDs in SPIR-V tests because the body block
is created before generating any of the loop code, rather than
only when the body is first referenced.
This commit is contained in:
David Neto 2015-07-17 17:11:22 -04:00
parent 222457054e
commit 3e6a33cedf
16 changed files with 458 additions and 453 deletions
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36
SPIRV/SpvBuilder.cpp
View file

@ -1738,19 +1738,8 @@ void Builder::endSwitch(std::vector<Block*>& /*segmentBlock*/)
// Comments in header
void Builder::makeNewLoop(bool loopTestFirst)
{
loops.push(Loop());
Loop& loop = loops.top();
loop.function = &getBuildPoint()->getParent();
loop.header = new Block(getUniqueId(), *loop.function);
loop.merge = new Block(getUniqueId(), *loop.function);
// Delaying creation of the loop body perturbs test results less,
// which makes for easier patch review.
// TODO(dneto): Create the loop body block here, instead of
// upon first use.
loop.body = 0;
loop.testFirst = loopTestFirst;
loop.isFirstIteration = 0;
loops.push(Loop(*this, loopTestFirst));
const Loop& loop = loops.top();
// The loop test is always emitted before the loop body.
// But if the loop test executes at the bottom of the loop, then
@ -1771,8 +1760,6 @@ void Builder::makeNewLoop(bool loopTestFirst)
// Generate code to defer the loop test until the second and
// subsequent iterations.
// A phi node determines whether we're on the first iteration.
loop.isFirstIteration = new Instruction(getUniqueId(), makeBoolType(), OpPhi);
// It's always the first iteration when coming from the preheader.
// All other branches to this loop header will need to indicate "false",
// but we don't yet know where they will come from.
@ -1792,7 +1779,6 @@ void Builder::makeNewLoop(bool loopTestFirst)
loop.function->addBlock(firstIterationCheck);
setBuildPoint(firstIterationCheck);
loop.body = new Block(getUniqueId(), *loop.function);
// Control flow after this "if" normally reconverges at the loop body.
// However, the loop test has a "break branch" out of this selection
// construct because it can transfer control to the loop merge block.
@ -1808,14 +1794,13 @@ void Builder::makeNewLoop(bool loopTestFirst)
void Builder::createLoopTestBranch(Id condition)
{
Loop& loop = loops.top();
const Loop& loop = loops.top();
// Generate the merge instruction. If the loop test executes before
// the body, then this is a loop merge. Otherwise the loop merge
// has already been generated and this is a conditional merge.
if (loop.testFirst) {
createMerge(OpLoopMerge, loop.merge, LoopControlMaskNone);
loop.body = new Block(getUniqueId(), *loop.function);
// Branching to the "body" block will keep control inside
// the loop.
createConditionalBranch(condition, loop.body, loop.merge);
@ -1842,7 +1827,7 @@ void Builder::createLoopTestBranch(Id condition)
void Builder::createBranchToBody()
{
Loop& loop = loops.top();
const Loop& loop = loops.top();
assert(loop.body);
// This is a reconvergence of control flow, so no merge instruction
@ -1870,7 +1855,7 @@ void Builder::createLoopExit()
// Close the innermost loop
void Builder::closeLoop()
{
Loop& loop = loops.top();
const Loop& loop = loops.top();
// Branch back to the top
createBranchToLoopHeaderFromInside(loop);
@ -2198,4 +2183,15 @@ void ValidationError(const char* error)
printf("Validation Error: %s\n", error);
}
Builder::Loop::Loop(Builder& builder, bool testFirstArg)
: function(&builder.getBuildPoint()->getParent()),
header(new Block(builder.getUniqueId(), *function)),
merge(new Block(builder.getUniqueId(), *function)),
body(new Block(builder.getUniqueId(), *function)),
testFirst(testFirstArg),
isFirstIteration(testFirst
? nullptr
: new Instruction(builder.getUniqueId(), builder.makeBoolType(), OpPhi))
{}
}; // end spv namespace