Index: docs/LangRef.rst =================================================================== --- docs/LangRef.rst +++ docs/LangRef.rst @@ -8371,18 +8371,17 @@ The '``fptrunc``' instruction casts a ``value`` from a larger :ref:`floating-point ` type to a smaller :ref:`floating-point -` type. If the value cannot fit (i.e. overflows) within the -destination type, ``ty2``, then the results are undefined. If the cast produces -an inexact result, how rounding is performed (e.g. truncation, also known as -round to zero) is undefined. +` type. +This instruction is assumed to execute in the default :ref:`floating-point +environment `. Example: """""""" .. code-block:: llvm - %X = fptrunc double 123.0 to float ; yields float:123.0 - %Y = fptrunc double 1.0E+300 to float ; yields undefined + %X = fptrunc double 16777217.0 to float ; yields float:16777216.0 + %Y = fptrunc double 1.0E+300 to half ; yields half:+infinity '``fpext .. to``' Instruction ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^