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[spirv-reader] Uses in phis count as uses 

This is required so we actually emit values that are only used
in phis.

Bug: tint:3, tint:215
Change-Id: I9d957a697839b8d09246905c3f28064f0bc01731
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/27701
Commit-Queue: David Neto <dneto@google.com>
Reviewed-by: dan sinclair <dsinclair@chromium.org>
This commit is contained in:
David Neto 2020-08-31 14:05:51 +00:00 committed by Commit Bot service account
parent c5d65cc917
commit 5a75a174d6
2 changed files with 145 additions and 58 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
src/reader/spirv/function.cc
View File

@ -3244,27 +3244,25 @@ void FunctionEmitter::FindValuesNeedingNamedOrHoistedDefinition() {
const auto* block_info = GetBlockInfo(block_id);
const auto block_pos = block_info->pos;
for (const auto& inst : *(block_info->basic_block)) {
// Update the usage span for IDs used by this instruction.
// But skip uses in OpPhi because they are handled differently.
if (inst.opcode() != SpvOpPhi) {
inst.ForEachInId([this, block_pos, block_info](const uint32_t* id_ptr) {
auto* def_info = GetDefInfo(*id_ptr);
if (def_info) {
def_info->num_uses++;
def_info->last_use_pos =
std::max(def_info->last_use_pos, block_pos);
// Update bookkeeping for locally-defined IDs used by this instruction.
inst.ForEachInId([this, block_pos, block_info](const uint32_t* id_ptr) {
auto* def_info = GetDefInfo(*id_ptr);
if (def_info) {
// Update usage count.
def_info->num_uses++;
// Update usage span.
def_info->last_use_pos = std::max(def_info->last_use_pos, block_pos);
// Determine whether this ID is defined in a different construct
// from this use.
const auto defining_block = block_order_[def_info->block_pos];
const auto* def_in_construct =
GetBlockInfo(defining_block)->construct;
if (def_in_construct != block_info->construct) {
def_info->used_in_another_construct = true;
}
// Determine whether this ID is defined in a different construct
// from this use.
const auto defining_block = block_order_[def_info->block_pos];
const auto* def_in_construct =
GetBlockInfo(defining_block)->construct;
if (def_in_construct != block_info->construct) {
def_info->used_in_another_construct = true;
}
});
}
}
});
if (inst.opcode() == SpvOpPhi) {
// Declare a name for the variable used to carry values to a phi.

167
src/reader/spirv/function_var_test.cc
View File

@ -1363,23 +1363,13 @@ TEST_F(SpvParserTest, EmitStatement_Phi_SingleBlockLoopIndex) {
}
}
}
VariableDeclStatement{
Variable{
x_4
none
__u32
{
Binary{
Identifier{x_2}
add
ScalarConstructor{1}
}
}
}
}
Assignment{
Identifier{x_2_phi}
Identifier{x_4}
Binary{
Identifier{x_2}
add
ScalarConstructor{1}
}
}
Assignment{
Identifier{x_3_phi}
@ -1495,6 +1485,13 @@ TEST_F(SpvParserTest, EmitStatement_Phi_MultiBlockLoopIndex) {
}
}
Loop{
VariableDeclStatement{
Variable{
x_4
function
__u32
}
}
VariableDeclStatement{
Variable{
x_2
@ -1524,18 +1521,12 @@ TEST_F(SpvParserTest, EmitStatement_Phi_MultiBlockLoopIndex) {
}
}
continuing {
VariableDeclStatement{
Variable{
x_4
none
__u32
{
Binary{
Identifier{x_2}
add
ScalarConstructor{1}
}
}
Assignment{
Identifier{x_4}
Binary{
Identifier{x_2}
add
ScalarConstructor{1}
}
}
Assignment{
@ -1632,6 +1623,13 @@ Loop{
ScalarConstructor{1}
}
Loop{
VariableDeclStatement{
Variable{
x_7
function
__u32
}
}
VariableDeclStatement{
Variable{
x_2
@ -1689,18 +1687,12 @@ Loop{
}
}
continuing {
VariableDeclStatement{
Variable{
x_7
none
__u32
{
Binary{
Identifier{x_4}
add
Identifier{x_6}
}
}
Assignment{
Identifier{x_7}
Binary{
Identifier{x_4}
add
Identifier{x_6}
}
}
Assignment{
@ -1957,6 +1949,103 @@ Return{}
)")) << ToString(fe.ast_body());
}
TEST_F(SpvParserTest, EmitStatement_UseInPhiCountsAsUse) {
// From crbug.com/215
// If the only use of a combinatorially computed ID is as the value
// in an OpPhi, then we still have to emit it. The algorithm fix
// is to always count uses in Phis.
// This is the reduced case from the bug report.
//
// The only use of %12 is in the phi.
// The only use of %11 is in %12.
// Both definintions need to be emitted to the output.
auto assembly = Preamble() + R"(
%100 = OpFunction %void None %voidfn
%10 = OpLabel
%11 = OpLogicalAnd %bool %true %true
%12 = OpLogicalNot %bool %11 ;
OpSelectionMerge %99 None
OpBranchConditional %true %20 %99
%20 = OpLabel
OpBranch %99
%99 = OpLabel
%101 = OpPhi %bool %11 %10 %12 %20
OpReturn
OpFunctionEnd
)";
auto* p = parser(test::Assemble(assembly));
ASSERT_TRUE(p->BuildAndParseInternalModuleExceptFunctions()) << assembly;
FunctionEmitter fe(p, *spirv_function(100));
EXPECT_TRUE(fe.EmitBody()) << p->error();
EXPECT_THAT(ToString(fe.ast_body()), Eq(R"(VariableDeclStatement{
Variable{
x_101_phi
function
__bool
}
}
VariableDeclStatement{
Variable{
x_11
none
__bool
{
Binary{
ScalarConstructor{true}
logical_and
ScalarConstructor{true}
}
}
}
}
VariableDeclStatement{
Variable{
x_12
none
__bool
{
UnaryOp{
not
Identifier{x_11}
}
}
}
}
Assignment{
Identifier{x_101_phi}
Identifier{x_11}
}
If{
(
ScalarConstructor{true}
)
{
Assignment{
Identifier{x_101_phi}
Identifier{x_12}
}
}
}
VariableDeclStatement{
Variable{
x_101
none
__bool
{
Identifier{x_101_phi}
}
}
}
Return{}
)")) << ToString(fe.ast_body());
}
} // namespace
} // namespace spirv
} // namespace reader