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[mlir][tosa] Check for isolated regions in tosa.while_loop #144865

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Merged
merged 1 commit into from
Jul 22, 2025
Merged

[mlir][tosa] Check for isolated regions in tosa.while_loop #144865

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57 changes: 32 additions & 25 deletions mlir/lib/Dialect/Tosa/Transforms/TosaValidation.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1200,6 +1200,28 @@ static bool isOpIsolatedWithinRegion(Operation *op, Region *region) {
});
}

static bool isRegionIsolatedFromAbove(Region &regionToCheck) {
bool noLiveInValue = true;
regionToCheck.walk([&noLiveInValue, &regionToCheck](Operation *op) {
if (!isOpIsolatedWithinRegion(op, &regionToCheck)) {
noLiveInValue = false;
return WalkResult::interrupt();
}
return WalkResult::advance();
});
return noLiveInValue;
}

LogicalResult checkIsolatedRegion(Operation *op, Region &regionToCheck,
StringRef regionName) {
if (isRegionIsolatedFromAbove(regionToCheck))
return success();
op->emitOpError()
<< "is not conformant to the TOSA specification. It requires the '"
<< regionName << "' region is isolated from above.\n";
return failure();
}

bool checkErrorIfCondIf(Operation *op) {
auto ifOp = dyn_cast<tosa::IfOp>(op);
if (!ifOp)
Expand Down Expand Up @@ -1236,32 +1258,17 @@ bool checkErrorIfCondIf(Operation *op) {
// used in then/else regions (see 'simplified' example above), so it
// must be rewritten to use the generic syntax in order to be conformant
// to the specification.
return failed(checkIsolatedRegion(op, ifOp.getThenGraph(), "then")) ||
failed(checkIsolatedRegion(op, ifOp.getElseGraph(), "else"));
}

// Returns true if the region uses no external input operands.
auto isIsolatedRegion = [](Region &regionToCheck) -> bool {
bool noLiveInValue = true;
regionToCheck.walk([&noLiveInValue, &regionToCheck](Operation *opInRegion) {
if (!isOpIsolatedWithinRegion(opInRegion, &regionToCheck)) {
noLiveInValue = false;
return WalkResult::interrupt();
}
return WalkResult::advance();
});
return noLiveInValue;
};

auto checkIsolatedRegion = [&](Region &regionToCheck,
StringRef regionName) -> LogicalResult {
if (isIsolatedRegion(regionToCheck))
return success();
op->emitOpError()
<< "is not conformant to the TOSA specification. It requires the '"
<< regionName << "' region is isolated from above.\n";
return failure();
};
bool checkErrorIfWhileLoop(Operation *op) {
auto whileOp = dyn_cast<tosa::WhileOp>(op);
if (!whileOp)
return true;

return failed(checkIsolatedRegion(ifOp.getThenGraph(), "then")) ||
failed(checkIsolatedRegion(ifOp.getElseGraph(), "else"));
return failed(checkIsolatedRegion(op, whileOp.getCondGraph(), "cond")) ||
failed(checkIsolatedRegion(op, whileOp.getBodyGraph(), "body"));
}

bool checkErrorIfScatter(Operation *op) {
Expand Down Expand Up @@ -1293,7 +1300,7 @@ LogicalResult TosaValidation::applyErrorIfCheck(Operation *op) {
if (!checkErrorIfResize(op) || !checkErrorIfMul(op) ||
!checkErrorIfTable(op) || !checkErrorIfRescale(op) ||
!checkErrorIfPad(op) || !checkErrorIfCondIf(op) ||
!checkErrorIfScatter(op))
!checkErrorIfWhileLoop(op) || !checkErrorIfScatter(op))
return failure();
return success();
}
Expand Down
57 changes: 57 additions & 0 deletions mlir/test/Dialect/Tosa/error_if_check.mlir
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Original file line number Diff line number Diff line change
Expand Up @@ -280,3 +280,60 @@ func.func @test_cond_if_isolated_from_above(%arg0: tensor<f32>, %arg1: tensor<f3
}) : (tensor<i1>, tensor<f32>, tensor<f32>) -> tensor<f32>
return %0 : tensor<f32>
}

// -----

func.func @test_while_loop_cond_not_isolated_from_above(%arg0: tensor<i32>, %arg1: tensor<i32>, %arg2: tensor<f32>) {
%0 = "tosa.const"() {values = dense<0> : tensor<i32>} : () -> tensor<i32>
// expected-error@+1 {{'tosa.while_loop' op is not conformant to the TOSA specification. It requires the 'cond' region is isolated from above.}}
%1 = "tosa.while_loop"(%0) ({
^bb0(%arg3: tensor<i32>):
%2 = "tosa.greater_equal"(%arg3, %arg1) : (tensor<i32>, tensor<i32>) -> tensor<i1>
%3 = "tosa.logical_not"(%2) : (tensor<i1>) -> tensor<i1>
tosa.yield %3 : tensor<i1>
}, {
^bb0(%arg3: tensor<i32>):
%2 = "tosa.const"() {values = dense<1> : tensor<i32>} : () -> tensor<i32>
%3 = "tosa.add"(%arg3, %2) : (tensor<i32>, tensor<i32>) -> tensor<i32>
tosa.yield %3 : tensor<i32>
}) : (tensor<i32>) -> (tensor<i32>)
return
}

// -----

func.func @test_while_loop_body_not_isolated_from_above(%arg0: tensor<i32>, %arg1: tensor<i32>, %arg2: tensor<f32>) {
%0 = "tosa.const"() {values = dense<0> : tensor<i32>} : () -> tensor<i32>
// expected-error@+1 {{'tosa.while_loop' op is not conformant to the TOSA specification. It requires the 'body' region is isolated from above.}}
%1 = "tosa.while_loop"(%0) ({
^bb0(%arg3: tensor<i32>):
%2 = "tosa.const"() {values = dense<1> : tensor<i32>} : () -> tensor<i32>
%3 = "tosa.greater_equal"(%arg3, %2) : (tensor<i32>, tensor<i32>) -> tensor<i1>
%4 = "tosa.logical_not"(%3) : (tensor<i1>) -> tensor<i1>
tosa.yield %4 : tensor<i1>
}, {
^bb0(%arg3: tensor<i32>):
%3 = "tosa.add"(%arg3, %arg1) : (tensor<i32>, tensor<i32>) -> tensor<i32>
tosa.yield %3 : tensor<i32>
}) : (tensor<i32>) -> (tensor<i32>)
return
}

// -----

// Check isolated while_loops are valid
func.func @test_while_loop_isolated_from_above(%arg0: tensor<f32>, %arg1: tensor<i32>) {
%0 = "tosa.const"() {values = dense<0> : tensor<i32>} : () -> tensor<i32>
%1:3 = "tosa.while_loop"(%0, %arg0, %arg1) ({
^bb0(%arg3: tensor<i32>, %arg4: tensor<f32>, %arg5: tensor<i32>):
%2 = "tosa.greater_equal"(%arg3, %arg5) : (tensor<i32>, tensor<i32>) -> tensor<i1>
%3 = "tosa.logical_not"(%2) : (tensor<i1>) -> tensor<i1>
"tosa.yield"(%3) : (tensor<i1>) -> ()
}, {
^bb0(%arg3: tensor<i32>, %arg4: tensor<f32>, %arg5: tensor<i32>):
%2 = "tosa.const"() {values = dense<1> : tensor<i32>} : () -> tensor<i32>
%3 = "tosa.add"(%arg3, %2) : (tensor<i32>, tensor<i32>) -> tensor<i32>
"tosa.yield"(%3, %arg4, %arg5) : (tensor<i32>, tensor<f32>, tensor<i32>) -> ()
}) : (tensor<i32>, tensor<f32>, tensor<i32>) -> (tensor<i32>, tensor<f32>, tensor<i32>)
return
}
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