mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-17 05:29:24 +00:00
Add a note that we should match rlwnm better
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30508 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
parent
3fe6c1d389
commit
cc96ac3a7d
@ -6,6 +6,40 @@ TODO:
|
||||
|
||||
===-------------------------------------------------------------------------===
|
||||
|
||||
We only produce the rlwnm instruction for rotate instructions. We should
|
||||
at least match stuff like:
|
||||
|
||||
unsigned rot_and(unsigned X, int Y) {
|
||||
unsigned T = (X << Y) | (X >> (32-Y));
|
||||
T &= 127;
|
||||
return T;
|
||||
}
|
||||
|
||||
_foo3:
|
||||
rlwnm r2, r3, r4, 0, 31
|
||||
rlwinm r3, r2, 0, 25, 31
|
||||
blr
|
||||
|
||||
... which is the basic pattern that should be written in the instr. It may
|
||||
also be useful for stuff like:
|
||||
|
||||
long long foo2(long long X, int C) {
|
||||
return X << (C&~32);
|
||||
}
|
||||
|
||||
which currently produces:
|
||||
|
||||
_foo2:
|
||||
rlwinm r2, r5, 0, 27, 25
|
||||
subfic r5, r2, 32
|
||||
slw r3, r3, r2
|
||||
srw r5, r4, r5
|
||||
or r3, r3, r5
|
||||
slw r4, r4, r2
|
||||
blr
|
||||
|
||||
===-------------------------------------------------------------------------===
|
||||
|
||||
Support 'update' load/store instructions. These are cracked on the G5, but are
|
||||
still a codesize win.
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user