This commit performs a small cleanup in the AArch64 backend - after
the MAdd and MSub variants have been extracted, the ALUOp enum is
used purely for binary integer operations.
Also, Inst::Mov has been renamed to Inst::Mov64 for consistency.
Copyright (c) 2020, Arm Limited.
* Don't substract 1 from end_addr in line program writing
Fixes#2173
* add testcase for end_sequence having offset past retq (#1)
* Update tests/all/debug/translate.rs
Co-authored-by: Gabor Greif <ggreif@gmail.com>
Co-authored-by: Gabor Greif <ggreif@gmail.com>
use approach with copysign for handling negative zero
format
refactor for better branch prediction
move copysign back to internal branch
format
fix
use abs instead branches
better comments
switch arms for better branch prediction
Baldrdash's API requires that there is at most one result in a register,
across all the possible register classes: in particular, it's not
possible to return an i64 value in a register while returning an v128
value in another register.
This patch adds a notion of "remaining register values", so this is
properly taking into account when choosing whether a return value may be
put into a register or not.
* entity: Fix typo in generated documentation
The same function documentation was used for `from_u32()` and `as_u32()`
while their behaviour is different
instead of always being relative to CARGO_MANIFEST_DIR, each use site is
responsible for either putting that variable or another one (set by a
build.rs) at the start of witx paths.
The logic for generation of shifts-by-immediate was not quite right. The result was that even
shifts by an amount known at compile time were being done by moving the shift immediate into %cl
and then doing a variable shift by %cl. The effect is worse than it sounds, because all of
those shift constants are small and often used in multiple places, so they were GVN'd up and
often ended up at the entry block of the function. Hence these were connected to the use points
by long live ranges which got spilled. So all in all, most of the win here comes from avoiding
spilling.
The problem was caused by this line, in the `Opcode::Ishl | Opcode::Ushr ..` case:
```
let (count, rhs) = if let Some(cst) = ctx.get_constant(inputs[1].insn) {
```
`inputs[]` appears to refer to this CLIF instruction's inputs, and bizarrely `inputs[].insn` all
refer to the instruction (the shift) itself. Hence `ctx.get_constant(inputs[1].insn)` asks
"does this shift instruction produce a constant" to which the answer is always "no", so the
shift-by-unknown amount code is always generated. The fix here is to change that expression to
```
let (count, rhs) = if let Some(cst) = ctx.get_input(insn, 1).constant {
```
`get_input`'s result conveniently includes a `constant` field of type `Option<u64>`, so we just
use that instead.
