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Merged
tancheng merged 4 commits into from
Jun 15, 2025
Merged

Handle block without argument but directly leveraging previous ops as liveins #34

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Handle block without argument but directly leveraging previous ops as…
tancheng Jun 15, 2025
f58a132
[test] Include test
tancheng Jun 15, 2025
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[cleanup] Format and comment
tancheng Jun 15, 2025
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tancheng Jun 15, 2025
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77 changes: 43 additions & 34 deletions lib/NeuraDialect/Transforms/TransformCtrlToDataFlowPass.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -49,7 +49,6 @@ void createPhiNodesForBlock(Block *block, OpBuilder &builder,
break;
}
}
assert(found_in_block_argument && "Live-in value defined outside the block must be passed as a block argument");
live_ins.push_back(operand);
}

Expand All @@ -75,49 +74,59 @@ void createPhiNodesForBlock(Block *block, OpBuilder &builder,
block->front().getLoc();

SmallVector<Value> phi_operands;

// Finds index of live_in in block arguments.
auto arg = dyn_cast<BlockArgument>(live_in);
assert(arg && "Expected live_in to be a block argument");
unsigned arg_index = arg.getArgNumber();

for (Block *pred : block->getPredecessors()) {
Value incoming;
Operation *term = pred->getTerminator();

// If it's a branch or cond_br, get the value passed into this block argument
if (auto br = dyn_cast<neura::Br>(term)) {
auto args = br.getArgs();
assert(arg_index < args.size());
incoming = args[arg_index];
} else if (auto condBr = dyn_cast<neura::CondBr>(term)) {
if (condBr.getTrueDest() == block) {
auto trueArgs = condBr.getTrueArgs();
assert(arg_index < trueArgs.size());
incoming = trueArgs[arg_index];
} else if (condBr.getFalseDest() == block) {
auto falseArgs = condBr.getFalseArgs();
assert(arg_index < falseArgs.size());
incoming = falseArgs[arg_index];
BlockArgument arg = dyn_cast<BlockArgument>(live_in);
// Handles the case where live_in is not a block argument.
if (!arg) {
phi_operands.push_back(live_in);
} else {
// Finds index of live_in in block arguments.
unsigned arg_index = arg.getArgNumber();
for (Block *pred : block->getPredecessors()) {
Value incoming;
Operation *term = pred->getTerminator();

// If it's a branch or cond_br, get the value passed into this block argument
if (auto br = dyn_cast<neura::Br>(term)) {
auto args = br.getArgs();
assert(arg_index < args.size());
incoming = args[arg_index];
} else if (auto condBr = dyn_cast<neura::CondBr>(term)) {
if (condBr.getTrueDest() == block) {
auto trueArgs = condBr.getTrueArgs();
assert(arg_index < trueArgs.size());
incoming = trueArgs[arg_index];
} else if (condBr.getFalseDest() == block) {
auto falseArgs = condBr.getFalseArgs();
assert(arg_index < falseArgs.size());
incoming = falseArgs[arg_index];
} else {
llvm::errs() << "cond_br does not target block:\n" << *block << "\n";
continue;
}
} else {
llvm::errs() << "cond_br does not target block:\n" << *block << "\n";
llvm::errs() << "Unknown branch terminator in block: " << *pred << "\n";
continue;
}
} else {
llvm::errs() << "Unknown branch terminator in block: " << *pred << "\n";
continue;
phi_operands.push_back(incoming);
}
phi_operands.push_back(incoming);
}

// Use default value if no incoming values found
assert(!phi_operands.empty());

// Create the phi node with dynamic number of operands
// Creates the phi node with dynamic number of operands.
auto phi_op = builder.create<neura::PhiOp>(loc, predicated_type, phi_operands);

// Replace block argument use with the phi result
arg.replaceAllUsesWith(phi_op.getResult());
// Saves users to be replaced *after* phi is constructed.
SmallVector<OpOperand *> uses_to_be_replaced;
for (OpOperand &use : live_in.getUses()) {
if (use.getOwner() != phi_op) {
uses_to_be_replaced.push_back(&use);
}
}
// Replaces live-in uses with the phi result.
for (OpOperand *use : uses_to_be_replaced) {
use->set(phi_op.getResult());
}
value_map[live_in] = phi_op.getResult();
}
}
Expand Down
68 changes: 68 additions & 0 deletions test/neura/ctrl/branch_no_arg.mlir
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Original file line number Diff line number Diff line change
@@ -0,0 +1,68 @@
// RUN: mlir-neura-opt %s \
// RUN: --assign-accelerator \
// RUN: --lower-llvm-to-neura \
// RUN: --leverage-predicated-value \
// RUN: | FileCheck %s

// RUN: mlir-neura-opt %s \
// RUN: --assign-accelerator \
// RUN: --lower-llvm-to-neura \
// RUN: --leverage-predicated-value \
// RUN: --transform-ctrl-to-data-flow \
// RUN: | FileCheck %s -check-prefix=CTRL2DATA

func.func @test(%in: i64) -> f32 {
%c0 = llvm.mlir.constant(0 : i64) : i64
%c1 = llvm.mlir.constant(1.0 : f32) : f32
%c2 = llvm.mlir.constant(2.0 : f32) : f32
%c3 = llvm.mlir.constant(3.0 : f32) : f32
%c4 = llvm.mlir.constant(4.0 : f32) : f32
%cond = llvm.icmp "eq" %in, %c0 : i64
llvm.cond_br %cond, ^bb2(%c3, %c4 : f32, f32), ^bb1

^bb1:
%a = llvm.fadd %c1, %c2 : f32
llvm.br ^bb3(%a : f32)

^bb2(%cc: f32, %cd: f32):
%b = llvm.fmul %cc, %cd : f32
llvm.br ^bb3(%b : f32)

^bb3(%v: f32):
return %v : f32
}

// CHECK: func.func @test(%arg0: i64) -> f32 attributes {accelerator = "neura"} {
// CHECK-NEXT: %0 = "neura.constant"() <{predicate = true, value = 0 : i64}> : () -> !neura.data<i64, i1>
// CHECK-NEXT: %1 = "neura.constant"() <{predicate = true, value = 1.000000e+00 : f32}> : () -> !neura.data<f32, i1>
// CHECK-NEXT: %2 = "neura.constant"() <{predicate = true, value = 2.000000e+00 : f32}> : () -> !neura.data<f32, i1>
// CHECK-NEXT: %3 = "neura.constant"() <{predicate = true, value = 3.000000e+00 : f32}> : () -> !neura.data<f32, i1>
// CHECK-NEXT: %4 = "neura.constant"() <{predicate = true, value = 4.000000e+00 : f32}> : () -> !neura.data<f32, i1>
// CHECK-NEXT: %5 = "neura.icmp"(%arg0, %0) <{cmpType = "eq"}> : (i64, !neura.data<i64, i1>) -> !neura.data<i1, i1>
// CHECK-NEXT: neura.cond_br %5 : !neura.data<i1, i1> then %3, %4 : !neura.data<f32, i1>, !neura.data<f32, i1> to ^bb2 else : to ^bb1
// CHECK-NEXT: ^bb1: // pred: ^bb0
// CHECK-NEXT: %6 = "neura.fadd"(%1, %2) : (!neura.data<f32, i1>, !neura.data<f32, i1>) -> !neura.data<f32, i1>
// CHECK-NEXT: neura.br %6 : !neura.data<f32, i1> to ^bb3
// CHECK-NEXT: ^bb2(%7: !neura.data<f32, i1>, %8: !neura.data<f32, i1>): // pred: ^bb0
// CHECK-NEXT: %9 = "neura.fmul"(%7, %8) : (!neura.data<f32, i1>, !neura.data<f32, i1>) -> !neura.data<f32, i1>
// CHECK-NEXT: neura.br %9 : !neura.data<f32, i1> to ^bb3
// CHECK-NEXT: ^bb3(%10: !neura.data<f32, i1>): // 2 preds: ^bb1, ^bb2
// CHECK-NEXT: "neura.return"(%10) : (!neura.data<f32, i1>) -> ()
// CHECK-NEXT: }

// CTRL2DATA: func.func @test(%arg0: i64) -> f32 attributes {accelerator = "neura"} {
// CTRL2DATA-NEXT: %0 = "neura.constant"() <{predicate = true, value = 0 : i64}> : () -> !neura.data<i64, i1>
// CTRL2DATA-NEXT: %1 = "neura.constant"() <{predicate = true, value = 1.000000e+00 : f32}> : () -> !neura.data<f32, i1>
// CTRL2DATA-NEXT: %2 = "neura.constant"() <{predicate = true, value = 2.000000e+00 : f32}> : () -> !neura.data<f32, i1>
// CTRL2DATA-NEXT: %3 = "neura.constant"() <{predicate = true, value = 3.000000e+00 : f32}> : () -> !neura.data<f32, i1>
// CTRL2DATA-NEXT: %4 = "neura.constant"() <{predicate = true, value = 4.000000e+00 : f32}> : () -> !neura.data<f32, i1>
// CTRL2DATA-NEXT: %5 = "neura.icmp"(%arg0, %0) <{cmpType = "eq"}> : (i64, !neura.data<i64, i1>) -> !neura.data<i1, i1>
// CTRL2DATA-NEXT: %6 = "neura.phi"(%1) : (!neura.data<f32, i1>) -> !neura.data<f32, i1>
// CTRL2DATA-NEXT: %7 = "neura.phi"(%2) : (!neura.data<f32, i1>) -> !neura.data<f32, i1>
// CTRL2DATA-NEXT: %8 = "neura.fadd"(%6, %7) : (!neura.data<f32, i1>, !neura.data<f32, i1>) -> !neura.data<f32, i1>
// CTRL2DATA-NEXT: %9 = "neura.phi"(%3) : (!neura.data<f32, i1>) -> !neura.data<f32, i1>
// CTRL2DATA-NEXT: %10 = "neura.phi"(%4) : (!neura.data<f32, i1>) -> !neura.data<f32, i1>
// CTRL2DATA-NEXT: %11 = "neura.fmul"(%9, %10) : (!neura.data<f32, i1>, !neura.data<f32, i1>) -> !neura.data<f32, i1>
// CTRL2DATA-NEXT: %12 = "neura.phi"(%8, %11) : (!neura.data<f32, i1>, !neura.data<f32, i1>) -> !neura.data<f32, i1>
// CTRL2DATA-NEXT: "neura.return"(%12) : (!neura.data<f32, i1>) -> ()
// CTRL2DATA-NEXT: }