7.1. Boolean

A boolean is either true or false. A boolean can be represented by an i1 in MLIR.

7.1.1. Declaration

A boolean value is declared with the keyword boolean. If the variable is not initialized explicitly, it is set to false (zero).

7.1.2. Literals

The following are the only two valid boolean literals:

true
false

7.1.3. Operations

The following operations are defined on boolean values. In all of the usage examples bool-expr means some boolean yielding expression.

Operation	Symbol	Usage	Associativity
parenthesis	`()`	`(bool-expr)`	N/A
negation	`not`	`not bool-expr`	right
logical or	`or`	`bool-expr or bool-expr`	left
logical xor	`xor`	`bool-expr xor bool-expr`	left
logical and	`and`	`bool-expr and bool-expr`	left
equals	`==`	`bool-expr == bool-expr`	left
not equals	`!=`	`bool-expr != bool-expr`	left

Unlike many languages the and and or operators do not short circuit evaluation. Therefore, both the left hand side and right hand side of an expression must always be evaluated.

This table specifies boolean operator precedence. Operators without lines between them have the same level of precedence.

Precedence	Operation
HIGHER	`not`
	`==` `!=`
	`and`
LOWER	`or` `xor`

7.1.4. Type Casting and Type Promotion

To see the types that boolean may be cast and/or promoted to, see the sections on Type Casting and Type Promotion respectively.