Naming is interesting here. Since 'truncate' refers to removing the least
significant digits, use 'ireduce' instead. The 'extend' use is fairly
established. Don't abbreviate, avoid unfortunate modern vernacular.
This instruction uses two type variables: input and output. Make sure that our
parser can handle it. The output type variable annotation is mandatory.
Add a ValueTypeSet::example() method which is used to provide better diagnostics
for a missing type variable.
Add new intcc and floatcc operand types for the immediate condition codes on
these instructions.
Add new IntCompare and FloatCompare instruction formats.
Add a generic match_enum() parser function that can match any identifier-like
enumerated operand kind that implements FromStr.
Define the icmp and fcmp instructions in case.py. Include documentation for the
condition codes with these two instructions.
Clarify the textual encoding of floating point numbers.
Don't allow decimal floating point since conversion to/from binary can produce
rounding problems on some (buggy) systems.
Add new immediate types for floating point and vector immediates.
Use new immediates to define the constant value instructions in meta.
Split the fconst instruction into two: f32const and f64const. This prevents
confusion about the interpretation of 64 immediate bits when generating an f32
constant.
Add an immvector ImmediateType. This immediate type is variable length, and
provides all the bits of a SIMD vector directly.
