[mlir][tosa] Interpret boolean values correctly in cast folder #147078
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@llvm/pr-subscribers-mlir-tosa @llvm/pr-subscribers-mlir Author: Luke Hutton (lhutton1) ChangesPreviously the cast folder would sign extend boolean values, leading "true" to be casted to a value of -1 instead of 1. This change ensures i1 values are zero extended, since i1 is used as a boolean value in TOSA. According to the TOSA spec, the result of a boolean cast with value "true" to another integer type should give a result of 1. Fixes #57951 Full diff: https://github.com/llvm/llvm-project/pull/147078.diff 2 Files Affected:
diff --git a/mlir/lib/Dialect/Tosa/IR/TosaCanonicalizations.cpp b/mlir/lib/Dialect/Tosa/IR/TosaCanonicalizations.cpp
index 1d21096e8920b..e2a2f2935b6b4 100644
--- a/mlir/lib/Dialect/Tosa/IR/TosaCanonicalizations.cpp
+++ b/mlir/lib/Dialect/Tosa/IR/TosaCanonicalizations.cpp
@@ -1301,7 +1301,8 @@ OpFoldResult CastOp::fold(FoldAdaptor adaptor) {
}
if (llvm::isa<IntegerType>(inETy) && llvm::isa<IntegerType>(outETy)) {
- auto unsignIn = llvm::cast<IntegerType>(inETy).isUnsignedInteger();
+ const auto inIntType = llvm::cast<IntegerType>(inETy);
+ auto unsignIn = inIntType.isUnsignedInteger();
bool trunc =
inETy.getIntOrFloatBitWidth() > outETy.getIntOrFloatBitWidth();
auto intVal = operand.getSplatValue<APInt>();
@@ -1309,7 +1310,8 @@ OpFoldResult CastOp::fold(FoldAdaptor adaptor) {
if (trunc) {
intVal = intVal.trunc(bitwidth);
- } else if (unsignIn) {
+ // i1 types are boolean in TOSA
+ } else if (unsignIn || inIntType.isInteger(1)) {
intVal = intVal.zext(bitwidth);
} else {
intVal = intVal.sext(bitwidth);
diff --git a/mlir/test/Dialect/Tosa/canonicalize.mlir b/mlir/test/Dialect/Tosa/canonicalize.mlir
index 27280807b0282..11c8d54fda055 100644
--- a/mlir/test/Dialect/Tosa/canonicalize.mlir
+++ b/mlir/test/Dialect/Tosa/canonicalize.mlir
@@ -1338,3 +1338,14 @@ func.func @no_fold_mul_result_exceeds_i32() -> tensor<i32> {
%3 = tosa.mul %0, %1, %2 : (tensor<i32>, tensor<i32>, tensor<1xi8>) -> tensor<i32>
return %3 : tensor<i32>
}
+
+// -----
+
+// CHECK-LABEL: @test_fold_i1_to_i32_cast
+// CHECK: %[[OUT:.*]] = "tosa.const"() <{values = dense<1> : tensor<i32>}> : () -> tensor<i32>
+// CHECK: return %[[OUT]] : tensor<i32>
+func.func @test_fold_i1_to_i32_cast() -> tensor<i32> {
+ %0 = "tosa.const"() <{values = dense<1> : tensor<i1>}> : () -> tensor<i1>
+ %1 = "tosa.cast"(%0) : (tensor<i1>) -> tensor<i32>
+ return %1 : tensor<i32>
+}
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✅ With the latest revision this PR passed the C/C++ code formatter. |
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Previously the cast folder would sign extend boolean values, leading "true" to be casted to a value of -1 instead of 1. This change ensures i1 values are zero extended, since i1 is used as a boolean value in TOSA. According to the TOSA spec, the result of a boolean cast with value "true" to another integer type should result in "1". Fixes llvm#57951 Change-Id: I21486cae0b8ad1cf7901e7b3eb92c1ad56c3797c
lhutton1
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GeorgeARM
approved these changes
Jul 15, 2025
This was referenced Jul 16, 2025
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/24/builds/10580 Here is the relevant piece of the build log for the reference |
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thanks for fixing this! |
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Previously the cast folder would sign extend boolean values, leading "true" to be casted to a value of -1 instead of 1. This change ensures i1 values are zero extended, since i1 is used as a boolean value in TOSA. According to the TOSA spec, the result of a boolean cast with value "true" to another integer type should give a result of 1.
Fixes #57951