[ir] Add a NextIteration instruction.

This CL adds a `NextIteration` instruction in order to branch from a
continue block back to the start of a loop. The `next_iteration` is
clearer then the `break-if false` pattern that was there previously.

BreakIf is retained and used when an `ast::BreakIf` is encountered as
it's clearer then the replaced `if` structure.

Bug: tint:1718
Change-Id: Ie6ce0db51c244866e2e99118bc00e4cfd2b3dc74
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/134600
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: James Price <jrprice@google.com>
This commit is contained in:
dan sinclair 2023-05-26 13:14:44 +00:00 committed by Dawn LUCI CQ
parent bdbbffbdfb
commit 0202531159
9 changed files with 113 additions and 24 deletions

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@ -1254,6 +1254,8 @@ if (tint_build_ir) {
"ir/loop.h", "ir/loop.h",
"ir/module.cc", "ir/module.cc",
"ir/module.h", "ir/module.h",
"ir/next_iteration.cc",
"ir/next_iteration.h",
"ir/return.cc", "ir/return.cc",
"ir/return.h", "ir/return.h",
"ir/store.cc", "ir/store.cc",

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@ -764,6 +764,8 @@ if(${TINT_BUILD_IR})
ir/loop.h ir/loop.h
ir/module.cc ir/module.cc
ir/module.h ir/module.h
ir/next_iteration.cc
ir/next_iteration.h
ir/return.cc ir/return.cc
ir/return.h ir/return.h
ir/store.cc ir/store.cc

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@ -205,6 +205,10 @@ ir::Return* Builder::Return(Function* func, utils::VectorRef<Value*> args) {
return ir.values.Create<ir::Return>(func, args); return ir.values.Create<ir::Return>(func, args);
} }
ir::NextIteration* Builder::NextIteration(Loop* loop) {
return ir.values.Create<ir::NextIteration>(loop);
}
ir::BreakIf* Builder::BreakIf(Value* condition, Loop* loop) { ir::BreakIf* Builder::BreakIf(Value* condition, Loop* loop) {
return ir.values.Create<ir::BreakIf>(condition, loop); return ir.values.Create<ir::BreakIf>(condition, loop);
} }

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@ -37,6 +37,7 @@
#include "src/tint/ir/load.h" #include "src/tint/ir/load.h"
#include "src/tint/ir/loop.h" #include "src/tint/ir/loop.h"
#include "src/tint/ir/module.h" #include "src/tint/ir/module.h"
#include "src/tint/ir/next_iteration.h"
#include "src/tint/ir/return.h" #include "src/tint/ir/return.h"
#include "src/tint/ir/store.h" #include "src/tint/ir/store.h"
#include "src/tint/ir/switch.h" #include "src/tint/ir/switch.h"
@ -337,6 +338,11 @@ class Builder {
/// @returns the instruction /// @returns the instruction
ir::Return* Return(Function* func, utils::VectorRef<Value*> args = {}); ir::Return* Return(Function* func, utils::VectorRef<Value*> args = {});
/// Creates a loop next iteration instruction
/// @param loop the loop being iterated
/// @returns the instruction
ir::NextIteration* NextIteration(Loop* loop);
/// Creates a loop break-if instruction /// Creates a loop break-if instruction
/// @param condition the break condition /// @param condition the break condition
/// @param loop the loop being iterated /// @param loop the loop being iterated

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@ -33,6 +33,7 @@
#include "src/tint/ir/if.h" #include "src/tint/ir/if.h"
#include "src/tint/ir/load.h" #include "src/tint/ir/load.h"
#include "src/tint/ir/loop.h" #include "src/tint/ir/loop.h"
#include "src/tint/ir/next_iteration.h"
#include "src/tint/ir/return.h" #include "src/tint/ir/return.h"
#include "src/tint/ir/store.h" #include "src/tint/ir/store.h"
#include "src/tint/ir/switch.h" #include "src/tint/ir/switch.h"
@ -428,6 +429,9 @@ void Disassembler::EmitBranch(const Branch* b) {
[&](const ir::ExitIf* ei) { out_ << "exit_if %b" << IdOf(ei->If()->Merge()); }, [&](const ir::ExitIf* ei) { out_ << "exit_if %b" << IdOf(ei->If()->Merge()); },
[&](const ir::ExitSwitch* es) { out_ << "exit_switch %b" << IdOf(es->Switch()->Merge()); }, [&](const ir::ExitSwitch* es) { out_ << "exit_switch %b" << IdOf(es->Switch()->Merge()); },
[&](const ir::ExitLoop* el) { out_ << "exit_loop %b" << IdOf(el->Loop()->Merge()); }, [&](const ir::ExitLoop* el) { out_ << "exit_loop %b" << IdOf(el->Loop()->Merge()); },
[&](const ir::NextIteration* ni) {
out_ << "next_iteration %b" << IdOf(ni->Loop()->Start());
},
[&](const ir::BreakIf* bi) { [&](const ir::BreakIf* bi) {
out_ << "break_if "; out_ << "break_if ";
EmitValue(bi->Condition()); EmitValue(bi->Condition());

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@ -575,7 +575,7 @@ class Impl {
} }
// Branch back to the start node if the continue target didn't branch out already // Branch back to the start node if the continue target didn't branch out already
if (NeedBranch()) { if (NeedBranch()) {
SetBranch(builder_.BreakIf(builder_.Constant(false), loop_inst)); SetBranch(builder_.NextIteration(loop_inst));
} }
} }
} }
@ -595,7 +595,7 @@ class Impl {
// Continue is always empty, just go back to the start // Continue is always empty, just go back to the start
current_flow_block_ = loop_inst->Continuing(); current_flow_block_ = loop_inst->Continuing();
SetBranch(builder_.BreakIf(builder_.Constant(false), loop_inst)); SetBranch(builder_.NextIteration(loop_inst));
{ {
ControlStackScope scope(this, loop_inst); ControlStackScope scope(this, loop_inst);
@ -676,7 +676,7 @@ class Impl {
if (stmt->continuing) { if (stmt->continuing) {
current_flow_block_ = loop_inst->Continuing(); current_flow_block_ = loop_inst->Continuing();
EmitStatement(stmt->continuing); EmitStatement(stmt->continuing);
SetBranch(builder_.BreakIf(builder_.Constant(false), loop_inst)); SetBranch(builder_.NextIteration(loop_inst));
} }
} }

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@ -381,7 +381,7 @@ TEST_F(IR_BuilderImplTest, Loop_WithContinue) {
EXPECT_EQ(1u, loop_flow->Start()->InboundBranches().Length()); EXPECT_EQ(1u, loop_flow->Start()->InboundBranches().Length());
EXPECT_EQ(1u, loop_flow->Continuing()->InboundBranches().Length()); EXPECT_EQ(1u, loop_flow->Continuing()->InboundBranches().Length());
EXPECT_EQ(2u, loop_flow->Merge()->InboundBranches().Length()); EXPECT_EQ(1u, loop_flow->Merge()->InboundBranches().Length());
EXPECT_EQ(1u, if_flow->True()->InboundBranches().Length()); EXPECT_EQ(1u, if_flow->True()->InboundBranches().Length());
EXPECT_EQ(1u, if_flow->False()->InboundBranches().Length()); EXPECT_EQ(1u, if_flow->False()->InboundBranches().Length());
EXPECT_EQ(1u, if_flow->Merge()->InboundBranches().Length()); EXPECT_EQ(1u, if_flow->Merge()->InboundBranches().Length());
@ -411,7 +411,7 @@ TEST_F(IR_BuilderImplTest, Loop_WithContinue) {
# Continuing block # Continuing block
%b3 = block { %b3 = block {
break_if false %b2 next_iteration %b2
} }
# Merge block # Merge block
@ -513,7 +513,7 @@ TEST_F(IR_BuilderImplTest, Loop_WithReturn) {
EXPECT_EQ(1u, loop_flow->Start()->InboundBranches().Length()); EXPECT_EQ(1u, loop_flow->Start()->InboundBranches().Length());
EXPECT_EQ(1u, loop_flow->Continuing()->InboundBranches().Length()); EXPECT_EQ(1u, loop_flow->Continuing()->InboundBranches().Length());
EXPECT_EQ(1u, loop_flow->Merge()->InboundBranches().Length()); EXPECT_EQ(0u, loop_flow->Merge()->InboundBranches().Length());
EXPECT_EQ(1u, if_flow->True()->InboundBranches().Length()); EXPECT_EQ(1u, if_flow->True()->InboundBranches().Length());
EXPECT_EQ(1u, if_flow->False()->InboundBranches().Length()); EXPECT_EQ(1u, if_flow->False()->InboundBranches().Length());
EXPECT_EQ(1u, if_flow->Merge()->InboundBranches().Length()); EXPECT_EQ(1u, if_flow->Merge()->InboundBranches().Length());
@ -521,21 +521,21 @@ TEST_F(IR_BuilderImplTest, Loop_WithReturn) {
EXPECT_EQ(Disassemble(m), EXPECT_EQ(Disassemble(m),
R"(%test_function = func():void [@compute @workgroup_size(1, 1, 1)] -> %b1 { R"(%test_function = func():void [@compute @workgroup_size(1, 1, 1)] -> %b1 {
%b1 = block { %b1 = block {
loop [s: %b2, c: %b3, m: %b4] loop [s: %b2, c: %b3]
%b2 = block { %b2 = block {
if true [t: %b5, f: %b6, m: %b7] if true [t: %b4, f: %b5, m: %b6]
# True block # True block
%b5 = block { %b4 = block {
ret ret
} }
# False block # False block
%b6 = block { %b5 = block {
exit_if %b7 exit_if %b6
} }
# Merge block # Merge block
%b7 = block { %b6 = block {
continue %b3 continue %b3
} }
@ -543,14 +543,9 @@ TEST_F(IR_BuilderImplTest, Loop_WithReturn) {
# Continuing block # Continuing block
%b3 = block { %b3 = block {
break_if false %b2 next_iteration %b2
} }
# Merge block
%b4 = block {
ret
}
} }
} }
)"); )");
@ -750,7 +745,7 @@ TEST_F(IR_BuilderImplTest, Loop_Nested) {
# Merge block # Merge block
%b18 = block { %b18 = block {
break_if false %b5 next_iteration %b5
} }
} }
@ -781,7 +776,7 @@ TEST_F(IR_BuilderImplTest, Loop_Nested) {
# Continuing block # Continuing block
%b3 = block { %b3 = block {
break_if false %b2 next_iteration %b2
} }
# Merge block # Merge block
@ -812,7 +807,7 @@ TEST_F(IR_BuilderImplTest, While) {
EXPECT_EQ(1u, flow->Start()->InboundBranches().Length()); EXPECT_EQ(1u, flow->Start()->InboundBranches().Length());
EXPECT_EQ(1u, flow->Continuing()->InboundBranches().Length()); EXPECT_EQ(1u, flow->Continuing()->InboundBranches().Length());
EXPECT_EQ(2u, flow->Merge()->InboundBranches().Length()); EXPECT_EQ(1u, flow->Merge()->InboundBranches().Length());
EXPECT_EQ(1u, if_flow->True()->InboundBranches().Length()); EXPECT_EQ(1u, if_flow->True()->InboundBranches().Length());
EXPECT_EQ(1u, if_flow->False()->InboundBranches().Length()); EXPECT_EQ(1u, if_flow->False()->InboundBranches().Length());
EXPECT_EQ(1u, if_flow->Merge()->InboundBranches().Length()); EXPECT_EQ(1u, if_flow->Merge()->InboundBranches().Length());
@ -842,7 +837,7 @@ TEST_F(IR_BuilderImplTest, While) {
# Continuing block # Continuing block
%b3 = block { %b3 = block {
break_if false %b2 next_iteration %b2
} }
# Merge block # Merge block
@ -873,7 +868,7 @@ TEST_F(IR_BuilderImplTest, While_Return) {
EXPECT_EQ(1u, flow->Start()->InboundBranches().Length()); EXPECT_EQ(1u, flow->Start()->InboundBranches().Length());
EXPECT_EQ(0u, flow->Continuing()->InboundBranches().Length()); EXPECT_EQ(0u, flow->Continuing()->InboundBranches().Length());
EXPECT_EQ(2u, flow->Merge()->InboundBranches().Length()); EXPECT_EQ(1u, flow->Merge()->InboundBranches().Length());
EXPECT_EQ(1u, if_flow->True()->InboundBranches().Length()); EXPECT_EQ(1u, if_flow->True()->InboundBranches().Length());
EXPECT_EQ(1u, if_flow->False()->InboundBranches().Length()); EXPECT_EQ(1u, if_flow->False()->InboundBranches().Length());
EXPECT_EQ(1u, if_flow->Merge()->InboundBranches().Length()); EXPECT_EQ(1u, if_flow->Merge()->InboundBranches().Length());
@ -903,7 +898,7 @@ TEST_F(IR_BuilderImplTest, While_Return) {
# Continuing block # Continuing block
%b3 = block { %b3 = block {
break_if false %b2 next_iteration %b2
} }
# Merge block # Merge block

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@ -0,0 +1,31 @@
// Copyright 2023 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "src/tint/ir/next_iteration.h"
#include "src/tint/ir/loop.h"
TINT_INSTANTIATE_TYPEINFO(tint::ir::NextIteration);
namespace tint::ir {
NextIteration::NextIteration(ir::Loop* loop) : Base(utils::Empty), loop_(loop) {
TINT_ASSERT(IR, loop_);
loop_->AddUsage(this);
loop_->Start()->AddInboundBranch(this);
}
NextIteration::~NextIteration() = default;
} // namespace tint::ir

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@ -0,0 +1,45 @@
// Copyright 2023 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef SRC_TINT_IR_NEXT_ITERATION_H_
#define SRC_TINT_IR_NEXT_ITERATION_H_
#include "src/tint/ir/branch.h"
#include "src/tint/utils/castable.h"
// Forward declarations
namespace tint::ir {
class Loop;
} // namespace tint::ir
namespace tint::ir {
/// A next iteration instruction.
class NextIteration : public utils::Castable<NextIteration, Branch> {
public:
/// Constructor
/// @param loop the loop being iterated
explicit NextIteration(ir::Loop* loop);
~NextIteration() override;
/// @returns the loop being iterated
const ir::Loop* Loop() const { return loop_; }
private:
ir::Loop* loop_ = nullptr;
};
} // namespace tint::ir
#endif // SRC_TINT_IR_NEXT_ITERATION_H_