The following is the syntax for constant expressions:
``trunc (CST to TYPE)``
- Truncate a constant to another type. The bit size of CST must be
- larger than the bit size of TYPE. Both types must be integers.
+ Perform the :ref:`trunc operation <i_trunc>` on constants.
``zext (CST to TYPE)``
- Zero extend a constant to another type. The bit size of CST must be
- smaller than the bit size of TYPE. Both types must be integers.
+ Perform the :ref:`zext operation <i_zext>` on constants.
``sext (CST to TYPE)``
- Sign extend a constant to another type. The bit size of CST must be
- smaller than the bit size of TYPE. Both types must be integers.
+ Perform the :ref:`sext operation <i_sext>` on constants.
``fptrunc (CST to TYPE)``
Truncate a floating point constant to another floating point type.
The size of CST must be larger than the size of TYPE. Both types
be scalars, or vectors of the same number of elements. If the value
won't fit in the floating point type, the results are undefined.
``ptrtoint (CST to TYPE)``
- Convert a pointer typed constant to the corresponding integer
- constant. ``TYPE`` must be an integer type. ``CST`` must be of
- pointer type. The ``CST`` value is zero extended, truncated, or
- unchanged to make it fit in ``TYPE``.
+ Perform the :ref:`ptrtoint operation <i_ptrtoint>` on constants.
``inttoptr (CST to TYPE)``
- Convert an integer constant to a pointer constant. TYPE must be a
- pointer type. CST must be of integer type. The CST value is zero
- extended, truncated, or unchanged to make it fit in a pointer size.
+ Perform the :ref:`inttoptr operation <i_inttoptr>` on constants.
This one is *really* dangerous!
``bitcast (CST to TYPE)``
- Convert a constant, CST, to another TYPE. The constraints of the
- operands are the same as those for the :ref:`bitcast
- instruction <i_bitcast>`.
+ Convert a constant, CST, to another TYPE.
+ The constraints of the operands are the same as those for the
+ :ref:`bitcast instruction <i_bitcast>`.
``addrspacecast (CST to TYPE)``
Convert a constant pointer or constant vector of pointer, CST, to another
TYPE in a different address space. The constraints of the operands are the
``select (COND, VAL1, VAL2)``
Perform the :ref:`select operation <i_select>` on constants.
``icmp COND (VAL1, VAL2)``
- Performs the :ref:`icmp operation <i_icmp>` on constants.
+ Perform the :ref:`icmp operation <i_icmp>` on constants.
``fcmp COND (VAL1, VAL2)``
- Performs the :ref:`fcmp operation <i_fcmp>` on constants.
+ Perform the :ref:`fcmp operation <i_fcmp>` on constants.
``extractelement (VAL, IDX)``
Perform the :ref:`extractelement operation <i_extractelement>` on
constants.
(casting) which all take a single operand and a type. They perform
various bit conversions on the operand.
+.. _i_trunc:
+
'``trunc .. to``' Instruction
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
%Z = trunc i32 122 to i1 ; yields i1:false
%W = trunc <2 x i16> <i16 8, i16 7> to <2 x i8> ; yields <i8 8, i8 7>
+.. _i_zext:
+
'``zext .. to``' Instruction
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
%Y = zext i1 true to i32 ; yields i32:1
%Z = zext <2 x i16> <i16 8, i16 7> to <2 x i32> ; yields <i32 8, i32 7>
+.. _i_sext:
+
'``sext .. to``' Instruction
^^^^^^^^^^^^^^^^^^^^^^^^^^^^