Expressions

Expressions

Hidet script supports the following expressions:

Literals

The literal expressions are the expressions that represent constant values. An integer literal (e.g., 1) has data type i32 by default. A floating point literal (e.g., 1.0) has data type float32 by default. A boolean literal (i.e., True and False) has data type bool by default. To define a literal with a specific data type, we can use the form <data type>(<value>) like f16(1.0) in the hidet script.

Variables

A variable is an expression that represents a memory location. A variable has a name and a data type. A variable can be defined in 1) the function parameters, 2) the variable declaration statement, 3) the for loop statement, 4) the for-mapping statement.

Unary expressions

A unary expression is an expression that applies a unary operator to a single operand. The unary operators supported in hidet script are:

  • +e: unary plus

  • -e: unary minus

  • ~e: get the address of e

  • bitwise_not(e): bitwise not, where bitwise_not refers to hidet.lang.bitwise_not

  • not cond: logical not

Binary expressions

A binary expression is an expression that applies a binary operator to two operands. The binary operators supported in hidet script are:

  • e1 + e2: addition

  • e1 - e2: subtraction

  • e1 * e2: multiplication

  • e1 / e2: division (we follow the semantics of c/c++ instead of python)

  • e1 % e2: remainder

  • e1 ** e2: power

  • e1 << e2: left shift

  • e1 >> e2: right shift

  • e1 & e2: bitwise and

  • e1 | e2: bitwise or

  • e1 ^ e2: bitwise xor

  • e1 and e2: logical and

  • e1 or e2: logical or

  • e1 == e2: equal

  • e1 != e2: not equal

  • e1 < e2: less than

  • e1 <= e2: less than or equal

  • e1 > e2: greater than

  • e1 >= e2: greater than or equal

Note on division: in python, the division operator / will produce a floating point result even if the operands are integers. However, in hidet script, we follow the semantics of c/c++: if the operands are integers, the division operator / will produce an integer result with floor(a / b) value; if the operands are floating point numbers, the division operator / will produce a floating point result.

Ternary expressions

A ternary expression is an expression that applies a ternary operator to three operands. The ternary operator supported in hidet script is:

  • true_expr if cond else false_expr: conditional expression

This operator has the same semantics as the conditional expression in c/c++: cond ? true_expr : false_expr.

Subscript and slice expressions

For a tensor t or tensor pointer

  • e1[p1, p2, ..., pn]: subscript expression

  • e1[p1, p2:q2, p3:, :p4, :, p5]: slice expression

  • func(e1, e2, ..., en): function call expression

  • address(e): get the address of e, where address refers to hidet.lang.address