Happens in Super Mario Sunshine. You could probably do something similar
for b == -1 (like we do for subfic), but I couldn't find any titles that
do this.
- Case 1: d == a
Before:
41 8B C7 mov eax,r15d
41 BF 00 00 00 00 mov r15d,0
44 2B F8 sub r15d,eax
After:
41 F7 DF neg r15d
- Case 2: d != a
Before:
BF 00 00 00 00 mov edi,0
41 2B FD sub edi,r13d
After:
41 8B FD mov edi,r13d
F7 DF neg edi
Consider the case where d and a refer to the same PowerPC register,
which is known to hold an immediate value by the RegCache. We place a
ReadWrite constraint on this register and bind it to an x86 register.
The RegCache then allocates a new register, initializes it with the
immediate, and returns a RCX64Reg for both d and a.
At this point information about the immediate value becomes unreachable.
In the case of subfx, this generates suboptimal code:
Before 1:
BF 1E 00 00 00 mov edi,1Eh <- done by RegCache
8B C7 mov eax,edi
8B FE mov edi,esi
2B F8 sub edi,eax
Before 2:
BE 00 AC 3F 80 mov esi,803FAC00h <- done by RegCache
8B C6 mov eax,esi
8B 75 EC mov esi,dword ptr [rbp-14h]
2B F0 sub esi,eax
The solution is to explicitly handle the constant a case before having
the RegCache allocate registers for us.
After 1:
8D 7E E2 lea edi,[rsi-1Eh]
After 2:
8B 75 EC mov esi,dword ptr [rbp-14h]
81 EE 00 AC 3F 80 sub esi,803FAC00h
Also provides operator!= for logical symmetry.
We can also take the arguments by value, as the arguments are trivially
copyable enum values which fit nicely into registers already.
operator[] performs a default construction if an object at the given key
doesn't exist before overwriting it with the one we provide in operator=
insert_or_assign performs optimal insertion by avoiding the default
construction if an entry doesn't exist.
Not a game changer, but it is essentially a "free" change.
Allows lookups to be done with std::string_view or any other string
type. This allows for non-allocating strings to be used with the name
lookup without needing to construct a std::string.
Cleans up some locks that explicitly specify the recursive mutex type in
it. Meant to be included with the previous commit that cleaned out
regular mutexes, but I forgot.
The config version should always be incremented whenever config is
changed, regardless of callbacks being suppressed or not.
Otherwise, getters can return stale data until another config change
(with callbacks enabled) happens.
C++17 allows omitting the mutex type, which makes for both less reading
and more flexibility (e.g. The mutex type can change and all occurrences
don't need to be updated).
