Having 18-bit opcodes means a block has at most 131,072 instructions
which is simply too big. All of these instructions cannot fit into the
L1 cache, which results in cache thrashing.
Signed-off-by: Ronald Caesar <github43132@proton.me>
We have enough bits in the opcode bitfield in instruction_t
to encode register classes (ADD_INT, ADD_FLOAT, ADD_VECTOR). However,
encoding the bit width (ADD_INT8, ADD_INT32) will massively increase the
amount of opcodes needed. So we replace `type` in ssa_version_t with
`bit_width`.
Signed-off-by: Ronald Caesar <github43132@proton.me>
Rule 4.2 states: "If a basic block is deemed cold, it should move to a
separate buffer." This violates Rule 3.1 Implicit Indexing. If v100 is
located at instructions[100] and we move it to a cold buffer, it id no
longer at index 100. If we keep the index 100 but store the data
elsewhere, you break the linear memory array performance benefits.
Hot-cols splitting will be done during code generation.
Signed-off-by: Ronald Caesar <github43132@proton.me>
- Replace value-returning IFs with Void IFs and explicit OPCODE_MERGE.
- Move SSA definitions to block exits to eliminate backpatching.
- Formalize Control Scope Stack for tracking yields and arity.
- Update loop peeling logic to respect new merge semantics.
Signed-off-by: Ronald Caesar <github43132@proton.me>
This attribute originally got removed because you could determine the
type of the variable based on the instruction opcode.
For example:
x1 = OPCODE_ADD_INT32 y1, 10.
x1 type is an int32.
We cannot apply this to control instructions because that would bloat
the amount of opcodes needed. An opcode has 10 bits, so we can define
1024 opcodes. Adding different variations for an `IF` instruction alone
would fill uo way to much space:
x1 = IF_INT8 (condition)
x1 = IF_INT16 (condition)
x1 = IF_INT32 (condition)
x1 = IF_UINT8 (condition)
x1 = IF_FLOAT (condition)
x1 = IF_VECTOR (condition)
etc...
So to solve creating unecessary opcodes, ssa_version_t will hold the
variable type instead:
x1 = IF (condition) DEF_TYPE: INT32
ssa_version_t.type = DEF_TYPE
Signed-off-by: Ronald Caesar <github43132@proton.me>
