Add documentation to the icmp instruction text for both signed and
unsigned overflow, making it very clear why unsigned overflow is
complicated and where to find it.
This move allows the `IntCC`/`FloatCC` enums to be used in both meta (for predicate matching) and in codegen. To avoid breaking any code dependent on the previous location of condcodes.rs (`cranelift-codegen/src/condcodes.rs`), the module is re-exported under `cranelift_codegen::ir`.
Instead of using MOVUPS to expensively load bits from memory, this change uses a predicate to optimize vconst without a memory access:
- when the 128-bit immediate is all zeroes in all bits, use PXOR to zero out an XMM register
- when the 128-bit immediate is all ones in all bits, use PCMPEQB to set an XMM register to all ones
This leaves the constant data in the constant pool, which may increase code size (TODO)
- `fill` attempted to use a GPR recipe, `fillSib32`, instead of its FPR equivalent, `ffillSib32` (code compiled without error but incorrect instructions were allowed, e.g. `v1 = regmove v0, %rdi -> %xmm0`
- `regmove` could be encoded with a GPR recipe, `rmov`, which hid the above incorrectness; now only FPR-to-FPR regmoves are allowed using the `frmov` recipe
This patch:
* removes the "default" opt level, on the basis that it has no definition and
is referred to nowhere in the compiler.
* renames the "fastest" level to "none". The resulting set of transformations
is unchanged.
* renames the "best" level to "speed_and_size". The resulting set of
transformations is unchanged.
* adds a new level, "speed". This is the same as "speed_and_size" except that
it omits transformations aimed only at reducing code size. Currently it
omits only the insn shrinking pass.
This function is responsible for 2.2% of all heap allocation (calls) in CL.
This change avoids all of them in the (presumably) common case where none of
the parameters require splitting. It also slightly reduces the compiler's
instruction count.
Converting something like iadd.i64 on a 32-bits architecture into a
iadd_imm.i64 will result in the instruction being legalized back to an
iadd.i64 later on, creating unnecessary churn.
This commit implements avoid doing so, and changes the target ISA to a
64-bits platform for tests than ran into this, as well as making sure
this won't happen on 32-bits platforms.
