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@llvm/pr-subscribers-mlir

@llvm/pr-subscribers-mlir-arith

Author: None (7FM)

diff --git a/mlir/lib/Dialect/Arith/IR/ArithOps.cpp b/mlir/lib/Dialect/Arith/IR/ArithOps.cpp
index 254f54d9e459e1..f2f23954d5c191 100644
--- a/mlir/lib/Dialect/Arith/IR/ArithOps.cpp
+++ b/mlir/lib/Dialect/Arith/IR/ArithOps.cpp
@@ -2314,7 +2314,8 @@ OpFoldResult arith::SelectOp::fold(FoldAdaptor adaptor) {
     return trueVal;
 
   // select %x, true, false => %x
-  if (getType().isInteger(1) && matchPattern(adaptor.getTrueValue(), m_One()) &&
+  if (getType().isSignlessInteger(1) &&
+      matchPattern(adaptor.getTrueValue(), m_One()) &&
       matchPattern(adaptor.getFalseValue(), m_Zero()))
     return condition;
 

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The pattern select %x, true, false => %x is only valid in case that the return type is identical to the type of %x (i.e., i1). Hence, the check isInteger(1) was replaced with isSignlessInteger(1).

Can we still replace by a bitcast when the types are different?

We should add a LIT test for the case that used to fail.

I agree, but at first glance, I couldn't find an upstream MLIR dialect that supports unsigned/signed constants to trigger this bug. But I might have missed a suitable dialect.

The pattern select %x, true, false => %x is only valid in case that the return type is identical to the type of %x (i.e., i1). Hence, the check isInteger(1) was replaced with isSignlessInteger(1).

Can we still replace by a bitcast when the types are different?

error: 'arith.bitcast' op result #0 must be signless-integer-or-float-like or memref of signless-integer or float, but got 'ui1'
I don't think so, at least not without further modifications.

We should add a LIT test for the case that used to fail.

I agree, but at first glance, I couldn't find an upstream MLIR dialect that supports unsigned/signed constants to trigger this bug. But I might have missed a suitable dialect.

How about adding a new test op to the test dialect? We already use test.with_bounds in arith tests.

We should add a LIT test for the case that used to fail.

I agree, but at first glance, I couldn't find an upstream MLIR dialect that supports unsigned/signed constants to trigger this bug. But I might have missed a suitable dialect.

How about adding a new test op to the test dialect? We already use test.with_bounds in arith tests.

Thanks for the hint! I didn't know that such a dialect existed.

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