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[spirv-reader] Allow multi-block continue construct being the entire loop 

The special case is not "single-block-loop" but rather the
case where a continue target is also its own loop header.
This can occur for single-block loops and multi-block loops.

Bug: tint:3
Change-Id: I4af1410793caf8b26a1f781e221fc0b395f07aa3
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/24320
Reviewed-by: dan sinclair <dsinclair@google.com>
This commit is contained in:
David Neto 2020-07-06 16:13:54 +00:00
parent 9b9a0b07da
commit 4c48622aa1
3 changed files with 277 additions and 93 deletions
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85
src/reader/spirv/function.cc
View File

@ -118,7 +118,7 @@
// //
// If CT(H) exists, then: // If CT(H) exists, then:
// //
// Pos(H) <= Pos(CT(H)), with equality exactly for single-block loops // Pos(H) <= Pos(CT(H))
// Pos(CT(H)) < Pos(M) // Pos(CT(H)) < Pos(M)
// //
// This gives us the fundamental ordering of blocks in relation to a // This gives us the fundamental ordering of blocks in relation to a
@ -140,15 +140,16 @@
// where H and d-e-f: blocks in the selection construct // where H and d-e-f: blocks in the selection construct
// where M(H) and n-o-p...: blocks after the selection construct // where M(H) and n-o-p...: blocks after the selection construct
// //
// Schematically, for a single-block loop construct headed by H, there are // Schematically, for a loop construct headed by H that is its own
// blocks in order from left to right: // continue construct, the blocks in order from left to right:
// //
// ...a-b-c H M(H) n-o-p... // ...a-b-c H=CT(H) d-e-f M(H) n-o-p...
// //
// where ...a-b-c: blocks before the loop // where ...a-b-c: blocks before the loop
// where H is the continue construct; CT(H)=H, and the loop construct // where H is the continue construct; CT(H)=H, and the loop construct
// is *empty* where M(H) and n-o-p...: blocks after the loop and // is *empty*
// continue constructs // where d-e-f... are other blocks in the continue construct
// where M(H) and n-o-p...: blocks after the continue construct
// //
// Schematically, for a multi-block loop construct headed by H, there are // Schematically, for a multi-block loop construct headed by H, there are
// blocks in order from left to right: // blocks in order from left to right:
@ -767,16 +768,14 @@ bool FunctionEmitter::RegisterMerges() {
if (block_id == succ) if (block_id == succ)
is_single_block_loop = true; is_single_block_loop = true;
}); });
block_info->is_single_block_loop = is_single_block_loop;
const auto ct = block_info->continue_for_header; const auto ct = block_info->continue_for_header;
if (is_single_block_loop && ct != block_id) { block_info->is_continue_entire_loop = ct == block_id;
if (is_single_block_loop && !block_info->is_continue_entire_loop) {
return Fail() << "Block " << block_id return Fail() << "Block " << block_id
<< " branches to itself but is not its own continue target"; << " branches to itself but is not its own continue target";
} else if (!is_single_block_loop && ct == block_id) {
return Fail() << "Loop header block " << block_id
<< " declares itself as its own continue target, but "
"does not branch to itself";
} }
// It's valid for a the header of a multi-block loop header to declare
// itself as its own continue target.
} }
return success(); return success();
} }
@ -799,7 +798,7 @@ bool FunctionEmitter::VerifyHeaderContinueMergeOrder() {
// Pos(H) < Pos(M(H)) // Pos(H) < Pos(M(H))
// //
// If CT(H) exists, then: // If CT(H) exists, then:
// Pos(H) <= Pos(CT(H)), with equality exactly for single-block loops // Pos(H) <= Pos(CT(H))
// Pos(CT(H)) < Pos(M) // Pos(CT(H)) < Pos(M)
// //
for (auto block_id : block_order_) { for (auto block_id : block_order_) {
@ -830,12 +829,8 @@ bool FunctionEmitter::VerifyHeaderContinueMergeOrder() {
// Furthermore, this is a loop header. // Furthermore, this is a loop header.
const auto* ct_info = GetBlockInfo(ct); const auto* ct_info = GetBlockInfo(ct);
const auto ct_pos = ct_info->pos; const auto ct_pos = ct_info->pos;
// Pos(H) <= Pos(CT(H)), with equality only for single-block loops. // Pos(H) <= Pos(CT(H))
if (header_info->is_single_block_loop && ct_pos != header_pos) { if (ct_pos < header_pos) {
Fail() << "Internal error: Single block loop. CT pos is not the "
"header pos. Should have already checked this";
}
if (!header_info->is_single_block_loop && (ct_pos <= header_pos)) {
Fail() << "Loop header " << header Fail() << "Loop header " << header
<< " does not dominate its continue target " << ct; << " does not dominate its continue target " << ct;
} }
@ -867,20 +862,24 @@ bool FunctionEmitter::LabelControlFlowConstructs() {
// be the associated header. Pop it off. // be the associated header. Pop it off.
// b. When you reach a header, push it on the stack. // b. When you reach a header, push it on the stack.
// c. When you reach a continue target, push it on the stack. // c. When you reach a continue target, push it on the stack.
// (A block can be both a header and a continue target, in the case // (A block can be both a header and a continue target.)
// of a single-block loop, in which case it should also be its
// own backedge block.)
// c. When you reach a block with an edge branching backward (in the // c. When you reach a block with an edge branching backward (in the
// structured order) to block T: // structured order) to block T:
// T should be a loop header, and the top of the stack should be a // T should be a loop header, and the top of the stack should be a
// continue target associated with T. // continue target associated with T.
// This is the end of the continue construct. Pop the continue // This is the end of the continue construct. Pop the continue
// target off the stack. // target off the stack.
// (Note: We pop the merge off first because a merge block that marks //
// Note: A loop header can declare itself as its own continue target.
//
// Note: For a single-block loop, that block is a header, its own
// continue target, and its own backedge block.
//
// Note: We pop the merge off first because a merge block that marks
// the end of one construct can be a single-block loop. So that block // the end of one construct can be a single-block loop. So that block
// is a merge, a header, a continue target, and a backedge block. // is a merge, a header, a continue target, and a backedge block.
// But we want to finish processing of the merge before dealing with // But we want to finish processing of the merge before dealing with
// the loop.) // the loop.
// //
// In the same scan, mark each basic block with the nearest enclosing // In the same scan, mark each basic block with the nearest enclosing
// header: the most recent header for which we haven't reached its merge // header: the most recent header for which we haven't reached its merge
@ -963,8 +962,10 @@ bool FunctionEmitter::LabelControlFlowConstructs() {
// in the block order, starting at the continue target, until just // in the block order, starting at the continue target, until just
// before the merge block. // before the merge block.
top = push_construct(depth, Construct::kContinue, ct, merge); top = push_construct(depth, Construct::kContinue, ct, merge);
// A single block loop has an empty loop construct. // A loop header that is its own continue target will have an
if (!header_info->is_single_block_loop) { // empty loop construct. Only create a loop construct when
// the continue target is *not* the same as the loop header.
if (header != ct) {
// From the interval rule, the loop construct consists of blocks // From the interval rule, the loop construct consists of blocks
// in the block order, starting at the header, until just // in the block order, starting at the header, until just
// before the continue target. // before the continue target.
@ -1706,9 +1707,9 @@ bool FunctionEmitter::EmitBasicBlock(const BlockInfo& block_info) {
// - It can't be kFunction, because there is only one of those, and it was // - It can't be kFunction, because there is only one of those, and it was
// already on the stack at the outermost level. // already on the stack at the outermost level.
// - We have at most one of kIfSelection, kSwitchSelection, or kLoop because // - We have at most one of kIfSelection, kSwitchSelection, or kLoop because
// each of those is headed by a block with a merge instruction, and the // each of those is headed by a block with a merge instruction (OpLoopMerge
// kIfSelection and kSwitchSelection header blocks end in different branch // for kLoop, and OpSelectionMerge for the others), and the kIfSelection and
// instructions. // kSwitchSelection header blocks end in different branch instructions.
// - A kContinue can contain a kContinue // - A kContinue can contain a kContinue
// This is possible in Vulkan SPIR-V, but Tint disallows this by the rule // This is possible in Vulkan SPIR-V, but Tint disallows this by the rule
// that a block can be continue target for at most one header block. See // that a block can be continue target for at most one header block. See
@ -1723,13 +1724,23 @@ bool FunctionEmitter::EmitBasicBlock(const BlockInfo& block_info) {
// starting at the first block of a continue construct. // starting at the first block of a continue construct.
// //
// The kContinue can't be the child of the other because either: // The kContinue can't be the child of the other because either:
// - Either it would be a single block loop but in that case there is no // - The other can't be kLoop because:
// kLoop construct for it, by construction. // - If the kLoop is for a different loop then the kContinue, then
// - The kContinue is in a loop that is not single-block; and the // the kContinue must be its own loop header, and so the same
// selection contains the kContinue block but not the loop block. That // block is two different loops. That's a contradiction.
// breaks dominance rules. That is, the continue target is dominated by // - If the kLoop is for a the same loop, then this is a contradiction
// that loop header, and so gets found on the outside before the // because a kContinue and its kLoop have disjoint block sets.
// selection is found. The selection is inside the outer loop. // - The other construct can't be a selection because:
// - The kContinue construct is the entire loop, i.e. the continue
// target is its own loop header block. But then the continue target
// has an OpLoopMerge instruction, which contradicts this block being
// a selection header.
// - The kContinue is in a multi-block loop that is has a non-empty
// kLoop; and the selection contains the kContinue block but not the
// loop block. That breaks dominance rules. That is, the continue
// target is dominated by that loop header, and so gets found by the
// block traversal on the outside before the selection is found. The
// selection is inside the outer loop.
// //
// So we fall into one of the following cases: // So we fall into one of the following cases:
// - We are entering 0 or 1 constructs, or // - We are entering 0 or 1 constructs, or
@ -1792,7 +1803,7 @@ bool FunctionEmitter::EmitBasicBlock(const BlockInfo& block_info) {
break; break;
case Construct::kContinue: case Construct::kContinue:
if (block_info.is_single_block_loop) { if (block_info.is_continue_entire_loop) {
if (!EmitLoopStart(construct)) { if (!EmitLoopStart(construct)) {
return false; return false;
} }

15
src/reader/spirv/function.h
View File

@ -108,9 +108,10 @@ struct BlockInfo {
/// If this block is a continue target, then this is the ID of the loop /// If this block is a continue target, then this is the ID of the loop
/// header. /// header.
uint32_t header_for_continue = 0; uint32_t header_for_continue = 0;
/// Is this block a single-block loop: A loop header that declares itself /// Is this block a continue target which is its own loop header block?
/// as its own continue target, and has branch to itself. /// In this case the continue construct is the entire loop. The associated
bool is_single_block_loop = false; /// "loop construct" is empty, and not represented.
bool is_continue_entire_loop = false;
/// The immediately enclosing structured construct. If this block is not /// The immediately enclosing structured construct. If this block is not
/// in the block order at all, then this is still nullptr. /// in the block order at all, then this is still nullptr.
@ -185,7 +186,7 @@ inline std::ostream& operator<<(std::ostream& o, const BlockInfo& bi) {
<< " merge_for_header: " << bi.merge_for_header << " merge_for_header: " << bi.merge_for_header
<< " continue_for_header: " << bi.continue_for_header << " continue_for_header: " << bi.continue_for_header
<< " header_for_merge: " << bi.header_for_merge << " header_for_merge: " << bi.header_for_merge
<< " single_block_loop: " << int(bi.is_single_block_loop) << "}"; << " is_continue_entire_loop: " << int(bi.is_continue_entire_loop) << "}";
return o; return o;
} }
@ -310,9 +311,9 @@ class FunctionEmitter {
/// @returns true if terminators are sane /// @returns true if terminators are sane
bool TerminatorsAreSane(); bool TerminatorsAreSane();
/// Populates merge-header cross-links and the |is_single_block_loop| member /// Populates merge-header cross-links and the |is_continue_entire_loop|
/// of BlockInfo. Also verifies that merge instructions go to blocks in /// member of BlockInfo. Also verifies that merge instructions go to blocks
/// the same function. Assumes basic blocks have been registered, and /// in the same function. Assumes basic blocks have been registered, and
/// terminators are sane. /// terminators are sane.
/// @returns false if registration fails /// @returns false if registration fails
bool RegisterMerges(); bool RegisterMerges();

270
src/reader/spirv/function_cfg_test.cc
View File

@ -374,7 +374,7 @@ TEST_F(SpvParserTest, RegisterMerges_NoMerges) {
EXPECT_EQ(bi->continue_for_header, 0u); EXPECT_EQ(bi->continue_for_header, 0u);
EXPECT_EQ(bi->header_for_merge, 0u); EXPECT_EQ(bi->header_for_merge, 0u);
EXPECT_EQ(bi->header_for_continue, 0u); EXPECT_EQ(bi->header_for_continue, 0u);
EXPECT_FALSE(bi->is_single_block_loop); EXPECT_FALSE(bi->is_continue_entire_loop);
} }
TEST_F(SpvParserTest, RegisterMerges_GoodSelectionMerge_BranchConditional) { TEST_F(SpvParserTest, RegisterMerges_GoodSelectionMerge_BranchConditional) {
@ -405,7 +405,7 @@ TEST_F(SpvParserTest, RegisterMerges_GoodSelectionMerge_BranchConditional) {
EXPECT_EQ(bi10->continue_for_header, 0u); EXPECT_EQ(bi10->continue_for_header, 0u);
EXPECT_EQ(bi10->header_for_merge, 0u); EXPECT_EQ(bi10->header_for_merge, 0u);
EXPECT_EQ(bi10->header_for_continue, 0u); EXPECT_EQ(bi10->header_for_continue, 0u);
EXPECT_FALSE(bi10->is_single_block_loop); EXPECT_FALSE(bi10->is_continue_entire_loop);
// Middle block is neither header nor merge // Middle block is neither header nor merge
const auto* bi20 = fe.GetBlockInfo(20); const auto* bi20 = fe.GetBlockInfo(20);
@ -414,7 +414,7 @@ TEST_F(SpvParserTest, RegisterMerges_GoodSelectionMerge_BranchConditional) {
EXPECT_EQ(bi20->continue_for_header, 0u); EXPECT_EQ(bi20->continue_for_header, 0u);
EXPECT_EQ(bi20->header_for_merge, 0u); EXPECT_EQ(bi20->header_for_merge, 0u);
EXPECT_EQ(bi20->header_for_continue, 0u); EXPECT_EQ(bi20->header_for_continue, 0u);
EXPECT_FALSE(bi20->is_single_block_loop); EXPECT_FALSE(bi20->is_continue_entire_loop);
// Merge block points to the header // Merge block points to the header
const auto* bi99 = fe.GetBlockInfo(99); const auto* bi99 = fe.GetBlockInfo(99);
@ -423,7 +423,7 @@ TEST_F(SpvParserTest, RegisterMerges_GoodSelectionMerge_BranchConditional) {
EXPECT_EQ(bi99->continue_for_header, 0u); EXPECT_EQ(bi99->continue_for_header, 0u);
EXPECT_EQ(bi99->header_for_merge, 10u); EXPECT_EQ(bi99->header_for_merge, 10u);
EXPECT_EQ(bi99->header_for_continue, 0u); EXPECT_EQ(bi99->header_for_continue, 0u);
EXPECT_FALSE(bi99->is_single_block_loop); EXPECT_FALSE(bi99->is_continue_entire_loop);
} }
TEST_F(SpvParserTest, RegisterMerges_GoodSelectionMerge_Switch) { TEST_F(SpvParserTest, RegisterMerges_GoodSelectionMerge_Switch) {
@ -454,7 +454,7 @@ TEST_F(SpvParserTest, RegisterMerges_GoodSelectionMerge_Switch) {
EXPECT_EQ(bi10->continue_for_header, 0u); EXPECT_EQ(bi10->continue_for_header, 0u);
EXPECT_EQ(bi10->header_for_merge, 0u); EXPECT_EQ(bi10->header_for_merge, 0u);
EXPECT_EQ(bi10->header_for_continue, 0u); EXPECT_EQ(bi10->header_for_continue, 0u);
EXPECT_FALSE(bi10->is_single_block_loop); EXPECT_FALSE(bi10->is_continue_entire_loop);
// Middle block is neither header nor merge // Middle block is neither header nor merge
const auto* bi20 = fe.GetBlockInfo(20); const auto* bi20 = fe.GetBlockInfo(20);
@ -463,7 +463,7 @@ TEST_F(SpvParserTest, RegisterMerges_GoodSelectionMerge_Switch) {
EXPECT_EQ(bi20->continue_for_header, 0u); EXPECT_EQ(bi20->continue_for_header, 0u);
EXPECT_EQ(bi20->header_for_merge, 0u); EXPECT_EQ(bi20->header_for_merge, 0u);
EXPECT_EQ(bi20->header_for_continue, 0u); EXPECT_EQ(bi20->header_for_continue, 0u);
EXPECT_FALSE(bi20->is_single_block_loop); EXPECT_FALSE(bi20->is_continue_entire_loop);
// Merge block points to the header // Merge block points to the header
const auto* bi99 = fe.GetBlockInfo(99); const auto* bi99 = fe.GetBlockInfo(99);
@ -472,7 +472,7 @@ TEST_F(SpvParserTest, RegisterMerges_GoodSelectionMerge_Switch) {
EXPECT_EQ(bi99->continue_for_header, 0u); EXPECT_EQ(bi99->continue_for_header, 0u);
EXPECT_EQ(bi99->header_for_merge, 10u); EXPECT_EQ(bi99->header_for_merge, 10u);
EXPECT_EQ(bi99->header_for_continue, 0u); EXPECT_EQ(bi99->header_for_continue, 0u);
EXPECT_FALSE(bi99->is_single_block_loop); EXPECT_FALSE(bi99->is_continue_entire_loop);
} }
TEST_F(SpvParserTest, RegisterMerges_GoodLoopMerge_SingleBlockLoop) { TEST_F(SpvParserTest, RegisterMerges_GoodLoopMerge_SingleBlockLoop) {
@ -503,7 +503,7 @@ TEST_F(SpvParserTest, RegisterMerges_GoodLoopMerge_SingleBlockLoop) {
EXPECT_EQ(bi10->continue_for_header, 0u); EXPECT_EQ(bi10->continue_for_header, 0u);
EXPECT_EQ(bi10->header_for_merge, 0u); EXPECT_EQ(bi10->header_for_merge, 0u);
EXPECT_EQ(bi10->header_for_continue, 0u); EXPECT_EQ(bi10->header_for_continue, 0u);
EXPECT_FALSE(bi10->is_single_block_loop); EXPECT_FALSE(bi10->is_continue_entire_loop);
// Single block loop is its own continue, and marked as single block loop. // Single block loop is its own continue, and marked as single block loop.
const auto* bi20 = fe.GetBlockInfo(20); const auto* bi20 = fe.GetBlockInfo(20);
@ -512,7 +512,7 @@ TEST_F(SpvParserTest, RegisterMerges_GoodLoopMerge_SingleBlockLoop) {
EXPECT_EQ(bi20->continue_for_header, 20u); EXPECT_EQ(bi20->continue_for_header, 20u);
EXPECT_EQ(bi20->header_for_merge, 0u); EXPECT_EQ(bi20->header_for_merge, 0u);
EXPECT_EQ(bi20->header_for_continue, 20u); EXPECT_EQ(bi20->header_for_continue, 20u);
EXPECT_TRUE(bi20->is_single_block_loop); EXPECT_TRUE(bi20->is_continue_entire_loop);
// Merge block points to the header // Merge block points to the header
const auto* bi99 = fe.GetBlockInfo(99); const auto* bi99 = fe.GetBlockInfo(99);
@ -521,10 +521,64 @@ TEST_F(SpvParserTest, RegisterMerges_GoodLoopMerge_SingleBlockLoop) {
EXPECT_EQ(bi99->continue_for_header, 0u); EXPECT_EQ(bi99->continue_for_header, 0u);
EXPECT_EQ(bi99->header_for_merge, 20u); EXPECT_EQ(bi99->header_for_merge, 20u);
EXPECT_EQ(bi99->header_for_continue, 0u); EXPECT_EQ(bi99->header_for_continue, 0u);
EXPECT_FALSE(bi99->is_single_block_loop); EXPECT_FALSE(bi99->is_continue_entire_loop);
} }
TEST_F(SpvParserTest, RegisterMerges_GoodLoopMerge_MultiBlockLoop_Branch) { TEST_F(SpvParserTest,
RegisterMerges_GoodLoopMerge_MultiBlockLoop_ContinueIsHeader) {
auto* p = parser(test::Assemble(CommonTypes() + R"(
%100 = OpFunction %void None %voidfn
%10 = OpLabel
OpBranch %20
%20 = OpLabel
OpLoopMerge %99 %20 None
OpBranch %40
%40 = OpLabel
OpBranch %20
%99 = OpLabel
OpReturn
OpFunctionEnd
)"));
ASSERT_TRUE(p->BuildAndParseInternalModuleExceptFunctions()) << p->error();
FunctionEmitter fe(p, *spirv_function(100));
fe.RegisterBasicBlocks();
EXPECT_TRUE(fe.RegisterMerges());
// Loop header points to continue (itself) and merge
const auto* bi20 = fe.GetBlockInfo(20);
ASSERT_NE(bi20, nullptr);
EXPECT_EQ(bi20->merge_for_header, 99u);
EXPECT_EQ(bi20->continue_for_header, 20u);
EXPECT_EQ(bi20->header_for_merge, 0u);
EXPECT_EQ(bi20->header_for_continue, 20u);
EXPECT_TRUE(bi20->is_continue_entire_loop);
// Backedge block, but is not a declared header, merge, or continue
const auto* bi40 = fe.GetBlockInfo(40);
ASSERT_NE(bi40, nullptr);
EXPECT_EQ(bi40->merge_for_header, 0u);
EXPECT_EQ(bi40->continue_for_header, 0u);
EXPECT_EQ(bi40->header_for_merge, 0u);
EXPECT_EQ(bi40->header_for_continue, 0u);
EXPECT_FALSE(bi40->is_continue_entire_loop);
// Merge block points to the header
const auto* bi99 = fe.GetBlockInfo(99);
ASSERT_NE(bi99, nullptr);
EXPECT_EQ(bi99->merge_for_header, 0u);
EXPECT_EQ(bi99->continue_for_header, 0u);
EXPECT_EQ(bi99->header_for_merge, 20u);
EXPECT_EQ(bi99->header_for_continue, 0u);
EXPECT_FALSE(bi99->is_continue_entire_loop);
}
TEST_F(SpvParserTest,
RegisterMerges_GoodLoopMerge_MultiBlockLoop_ContinueIsNotHeader_Branch) {
auto* p = parser(test::Assemble(CommonTypes() + R"( auto* p = parser(test::Assemble(CommonTypes() + R"(
%100 = OpFunction %void None %voidfn %100 = OpFunction %void None %voidfn
@ -558,7 +612,7 @@ TEST_F(SpvParserTest, RegisterMerges_GoodLoopMerge_MultiBlockLoop_Branch) {
EXPECT_EQ(bi20->continue_for_header, 40u); EXPECT_EQ(bi20->continue_for_header, 40u);
EXPECT_EQ(bi20->header_for_merge, 0u); EXPECT_EQ(bi20->header_for_merge, 0u);
EXPECT_EQ(bi20->header_for_continue, 0u); EXPECT_EQ(bi20->header_for_continue, 0u);
EXPECT_FALSE(bi20->is_single_block_loop); EXPECT_FALSE(bi20->is_continue_entire_loop);
// Continue block points to header // Continue block points to header
const auto* bi40 = fe.GetBlockInfo(40); const auto* bi40 = fe.GetBlockInfo(40);
@ -567,7 +621,7 @@ TEST_F(SpvParserTest, RegisterMerges_GoodLoopMerge_MultiBlockLoop_Branch) {
EXPECT_EQ(bi40->continue_for_header, 0u); EXPECT_EQ(bi40->continue_for_header, 0u);
EXPECT_EQ(bi40->header_for_merge, 0u); EXPECT_EQ(bi40->header_for_merge, 0u);
EXPECT_EQ(bi40->header_for_continue, 20u); EXPECT_EQ(bi40->header_for_continue, 20u);
EXPECT_FALSE(bi40->is_single_block_loop); EXPECT_FALSE(bi40->is_continue_entire_loop);
// Merge block points to the header // Merge block points to the header
const auto* bi99 = fe.GetBlockInfo(99); const auto* bi99 = fe.GetBlockInfo(99);
@ -576,11 +630,12 @@ TEST_F(SpvParserTest, RegisterMerges_GoodLoopMerge_MultiBlockLoop_Branch) {
EXPECT_EQ(bi99->continue_for_header, 0u); EXPECT_EQ(bi99->continue_for_header, 0u);
EXPECT_EQ(bi99->header_for_merge, 20u); EXPECT_EQ(bi99->header_for_merge, 20u);
EXPECT_EQ(bi99->header_for_continue, 0u); EXPECT_EQ(bi99->header_for_continue, 0u);
EXPECT_FALSE(bi99->is_single_block_loop); EXPECT_FALSE(bi99->is_continue_entire_loop);
} }
TEST_F(SpvParserTest, TEST_F(
RegisterMerges_GoodLoopMerge_MultiBlockLoop_BranchConditional) { SpvParserTest,
RegisterMerges_GoodLoopMerge_MultiBlockLoop_ContinueIsNotHeader_BranchConditional) {
auto* p = parser(test::Assemble(CommonTypes() + R"( auto* p = parser(test::Assemble(CommonTypes() + R"(
%100 = OpFunction %void None %voidfn %100 = OpFunction %void None %voidfn
@ -614,7 +669,7 @@ TEST_F(SpvParserTest,
EXPECT_EQ(bi20->continue_for_header, 40u); EXPECT_EQ(bi20->continue_for_header, 40u);
EXPECT_EQ(bi20->header_for_merge, 0u); EXPECT_EQ(bi20->header_for_merge, 0u);
EXPECT_EQ(bi20->header_for_continue, 0u); EXPECT_EQ(bi20->header_for_continue, 0u);
EXPECT_FALSE(bi20->is_single_block_loop); EXPECT_FALSE(bi20->is_continue_entire_loop);
// Continue block points to header // Continue block points to header
const auto* bi40 = fe.GetBlockInfo(40); const auto* bi40 = fe.GetBlockInfo(40);
@ -623,7 +678,7 @@ TEST_F(SpvParserTest,
EXPECT_EQ(bi40->continue_for_header, 0u); EXPECT_EQ(bi40->continue_for_header, 0u);
EXPECT_EQ(bi40->header_for_merge, 0u); EXPECT_EQ(bi40->header_for_merge, 0u);
EXPECT_EQ(bi40->header_for_continue, 20u); EXPECT_EQ(bi40->header_for_continue, 20u);
EXPECT_FALSE(bi40->is_single_block_loop); EXPECT_FALSE(bi40->is_continue_entire_loop);
// Merge block points to the header // Merge block points to the header
const auto* bi99 = fe.GetBlockInfo(99); const auto* bi99 = fe.GetBlockInfo(99);
@ -632,7 +687,7 @@ TEST_F(SpvParserTest,
EXPECT_EQ(bi99->continue_for_header, 0u); EXPECT_EQ(bi99->continue_for_header, 0u);
EXPECT_EQ(bi99->header_for_merge, 20u); EXPECT_EQ(bi99->header_for_merge, 20u);
EXPECT_EQ(bi99->header_for_continue, 0u); EXPECT_EQ(bi99->header_for_continue, 0u);
EXPECT_FALSE(bi99->is_single_block_loop); EXPECT_FALSE(bi99->is_continue_entire_loop);
} }
TEST_F(SpvParserTest, RegisterMerges_SelectionMerge_BadTerminator) { TEST_F(SpvParserTest, RegisterMerges_SelectionMerge_BadTerminator) {
@ -920,33 +975,6 @@ TEST_F(SpvParserTest, RegisterMerges_SingleBlockLoop_NotItsOwnContinue) {
Eq("Block 20 branches to itself but is not its own continue target")); Eq("Block 20 branches to itself but is not its own continue target"));
} }
TEST_F(SpvParserTest, RegisterMerges_NotSingleBlockLoop_IsItsOwnContinue) {
auto* p = parser(test::Assemble(CommonTypes() + R"(
%100 = OpFunction %void None %voidfn
%10 = OpLabel
OpBranch %20
%20 = OpLabel
OpLoopMerge %99 %20 None
OpBranchConditional %cond %30 %99
%30 = OpLabel
OpBranch %20
%99 = OpLabel
OpReturn
OpFunctionEnd
)"));
ASSERT_TRUE(p->BuildAndParseInternalModuleExceptFunctions()) << p->error();
FunctionEmitter fe(p, *spirv_function(100));
fe.RegisterBasicBlocks();
EXPECT_FALSE(fe.RegisterMerges());
EXPECT_THAT(p->error(), Eq("Loop header block 20 declares itself as its own "
"continue target, but does not branch to itself"));
}
TEST_F(SpvParserTest, ComputeBlockOrder_OneBlock) { TEST_F(SpvParserTest, ComputeBlockOrder_OneBlock) {
auto* p = parser(test::Assemble(CommonTypes() + R"( auto* p = parser(test::Assemble(CommonTypes() + R"(
%100 = OpFunction %void None %voidfn %100 = OpFunction %void None %voidfn
@ -3026,7 +3054,9 @@ TEST_F(SpvParserTest, LabelControlFlowConstructs_SingleBlockLoop) {
EXPECT_EQ(fe.GetBlockInfo(99)->construct, constructs[0].get()); EXPECT_EQ(fe.GetBlockInfo(99)->construct, constructs[0].get());
} }
TEST_F(SpvParserTest, LabelControlFlowConstructs_MultiBlockLoop) { TEST_F(SpvParserTest,
LabelControlFlowConstructs_MultiBlockLoop_HeaderIsNotContinue) {
// In this case, we have a continue construct and a non-empty loop construct.
auto assembly = CommonTypes() + R"( auto assembly = CommonTypes() + R"(
%100 = OpFunction %void None %voidfn %100 = OpFunction %void None %voidfn
@ -3073,6 +3103,54 @@ TEST_F(SpvParserTest, LabelControlFlowConstructs_MultiBlockLoop) {
EXPECT_EQ(fe.GetBlockInfo(99)->construct, constructs[0].get()); EXPECT_EQ(fe.GetBlockInfo(99)->construct, constructs[0].get());
} }
TEST_F(SpvParserTest,
LabelControlFlowConstructs_MultiBlockLoop_HeaderIsContinue) {
// In this case, we have only a continue construct and no loop construct.
auto assembly = CommonTypes() + R"(
%100 = OpFunction %void None %voidfn
%10 = OpLabel
OpBranch %20
%20 = OpLabel
OpLoopMerge %99 %20 None
OpBranchConditional %cond %30 %99
%30 = OpLabel
OpBranch %40
%40 = OpLabel
OpBranch %50
%50 = OpLabel
OpBranch %20
%99 = OpLabel
OpReturn
OpFunctionEnd
)";
auto* p = parser(test::Assemble(assembly));
ASSERT_TRUE(p->BuildAndParseInternalModuleExceptFunctions()) << p->error();
FunctionEmitter fe(p, *spirv_function(100));
fe.RegisterBasicBlocks();
fe.ComputeBlockOrderAndPositions();
fe.RegisterMerges();
EXPECT_TRUE(fe.LabelControlFlowConstructs());
const auto& constructs = fe.constructs();
EXPECT_THAT(ToString(constructs), Eq(R"(ConstructList{
Construct{ Function [0,6) begin_id:10 end_id:0 depth:0 parent:null }
Construct{ Continue [1,5) begin_id:20 end_id:99 depth:1 parent:Function@10 in-c:Continue@20 }
})")) << constructs;
// The block records the nearest enclosing construct.
EXPECT_EQ(fe.GetBlockInfo(10)->construct, constructs[0].get());
EXPECT_EQ(fe.GetBlockInfo(20)->construct, constructs[1].get());
EXPECT_EQ(fe.GetBlockInfo(30)->construct, constructs[1].get());
EXPECT_EQ(fe.GetBlockInfo(40)->construct, constructs[1].get());
EXPECT_EQ(fe.GetBlockInfo(50)->construct, constructs[1].get());
EXPECT_EQ(fe.GetBlockInfo(99)->construct, constructs[0].get());
}
TEST_F(SpvParserTest, TEST_F(SpvParserTest,
LabelControlFlowConstructs_MergeBlockIsAlsoSingleBlockLoop) { LabelControlFlowConstructs_MergeBlockIsAlsoSingleBlockLoop) {
auto assembly = CommonTypes() + R"( auto assembly = CommonTypes() + R"(
@ -4482,8 +4560,9 @@ TEST_F(SpvParserTest,
EXPECT_EQ(bi40->succ_edge[20], EdgeKind::kBack); EXPECT_EQ(bi40->succ_edge[20], EdgeKind::kBack);
} }
TEST_F(SpvParserTest, TEST_F(
ClassifyCFGEdges_BackEdge_MultiBlockLoop_MultiBlockContinueConstruct) { SpvParserTest,
ClassifyCFGEdges_BackEdge_MultiBlockLoop_MultiBlockContinueConstruct_ContinueIsNotHeader) {
auto assembly = CommonTypes() + R"( auto assembly = CommonTypes() + R"(
%100 = OpFunction %void None %voidfn %100 = OpFunction %void None %voidfn
@ -4517,6 +4596,42 @@ TEST_F(SpvParserTest,
EXPECT_EQ(bi50->succ_edge[20], EdgeKind::kBack); EXPECT_EQ(bi50->succ_edge[20], EdgeKind::kBack);
} }
TEST_F(
SpvParserTest,
ClassifyCFGEdges_BackEdge_MultiBlockLoop_MultiBlockContinueConstruct_ContinueIsHeader) {
auto assembly = CommonTypes() + R"(
%100 = OpFunction %void None %voidfn
%10 = OpLabel
OpBranch %20
%20 = OpLabel
OpLoopMerge %99 %20 None ; continue target
OpBranch %30
%30 = OpLabel
OpBranch %40
%40 = OpLabel
OpBranch %50
%50 = OpLabel
OpBranchConditional %cond %20 %99 ; good back edge
%99 = OpLabel ; outer merge
OpReturn
)";
auto* p = parser(test::Assemble(assembly));
ASSERT_TRUE(p->BuildAndParseInternalModuleExceptFunctions()) << p->error();
FunctionEmitter fe(p, *spirv_function(100));
EXPECT_TRUE(FlowClassifyCFGEdges(&fe)) << p->error();
auto* bi50 = fe.GetBlockInfo(50);
ASSERT_NE(bi50, nullptr);
EXPECT_EQ(bi50->succ_edge.count(20), 1u);
EXPECT_EQ(bi50->succ_edge[20], EdgeKind::kBack);
}
TEST_F(SpvParserTest, ClassifyCFGEdges_PrematureExitFromContinueConstruct) { TEST_F(SpvParserTest, ClassifyCFGEdges_PrematureExitFromContinueConstruct) {
auto assembly = CommonTypes() + R"( auto assembly = CommonTypes() + R"(
%100 = OpFunction %void None %voidfn %100 = OpFunction %void None %voidfn
@ -8534,6 +8649,63 @@ Return{}
)")) << ToString(fe.ast_body()); )")) << ToString(fe.ast_body());
} }
TEST_F(SpvParserTest, EmitBody_Loop_MultiBlockContinueIsEntireLoop) {
// Test case where both branches exit. e.g both go to merge.
auto* p = parser(test::Assemble(CommonTypes() + R"(
%100 = OpFunction %void None %voidfn
%10 = OpLabel
OpStore %var %uint_0
OpBranch %20
%20 = OpLabel ; its own continue target
OpStore %var %uint_1
OpLoopMerge %99 %20 None
OpBranch %80
%80 = OpLabel
OpStore %var %uint_2
OpBranchConditional %cond %99 %20
%99 = OpLabel
OpStore %var %uint_3
OpReturn
OpFunctionEnd
)"));
ASSERT_TRUE(p->BuildAndParseInternalModuleExceptFunctions()) << p->error();
FunctionEmitter fe(p, *spirv_function(100));
EXPECT_TRUE(fe.EmitBody()) << p->error();
EXPECT_THAT(ToString(fe.ast_body()), Eq(R"(Assignment{
Identifier{var}
ScalarConstructor{0}
}
Loop{
Assignment{
Identifier{var}
ScalarConstructor{1}
}
Assignment{
Identifier{var}
ScalarConstructor{2}
}
If{
(
ScalarConstructor{false}
)
{
Break{}
}
}
}
Assignment{
Identifier{var}
ScalarConstructor{3}
}
Return{}
)")) << ToString(fe.ast_body());
}
TEST_F(SpvParserTest, EmitBody_Loop_Never) { TEST_F(SpvParserTest, EmitBody_Loop_Never) {
// Test case where both branches exit. e.g both go to merge. // Test case where both branches exit. e.g both go to merge.
auto* p = parser(test::Assemble(CommonTypes() + R"( auto* p = parser(test::Assemble(CommonTypes() + R"(