The DataFlowGraph::replace(inst) method returns an instruction builder
that will replace an instruction in-place.
This will be used when transforming instructions, replacing an old
instruction with a new (legal) way of computing its primary value. Since
primary result values are essentially instruction pointers, this is the
only way of replacing the definition of a value.
If secondary result values match the old instruction in both number and
types, they can be reused. If not, added a detach_secondary_results()
method for detaching old secondary values.
All the InstrBuilder methods now consume the builder, and the non-leaf
methods return the dfg mutable reference they were holding.
This makes it possible to construct instruction builders that are only
safe to use once because they are doing more advanced value rewriting.
Distinguish the lifetime of the Cursor and its referenced function
layout.
Use two separate function lifetimes: 'fc and 'fd. The borrow checker
seems to get confused if we don't.
All of the instruction format an opcode methods are emitted as an
InstBuilder trait instead of adding them to the Bulder struct directly.
The methods only make use of the InstBuilderBase methods to create new
instructions.
This makes it possible to reuse the InstBuilder trait for different ways
of inserting instructions.
Give these crates each a more standard directory layout with sources in
a 'src' sub-sirectory and Cargo.toml in the top lib/foo directory.
Add license and description fields to each.
The build script for the cretonne crate now lives in
'lib/cretonne/build.rs' separating it from the normal library sources
under 'lib/cretonne/src'.
