piwalker/dolphin
1
0
Fork 0
mirror of https://github.com/dolphin-emu/dolphin.git synced 2024-11-14 21:37:52 -07:00
Code Issues Actions Packages Projects Releases Wiki Activity

Merge pull request #11916 from JosJuice/ppcanalyst-reorder-loop

Browse Source 
PPCAnalyst: Reduce number of iterations in ReorderInstructionsCore
This commit is contained in:
Admiral H. Curtiss 2023-07-01 01:06:53 +02:00 committed by GitHub
commit ed4403537f
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 57 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

92
Source/Core/Core/PowerPC/PPCAnalyst.cpp
View File

@ -470,52 +470,74 @@ static bool isCror(const CodeOp& a)
void PPCAnalyzer::ReorderInstructionsCore(u32 instructions, CodeOp* code, bool reverse,
ReorderType type) const
{
// Bubbling an instruction sometimes reveals another opportunity to bubble an instruction, so do
// multiple passes.
// Instruction Reordering Pass
// Carry pass: bubble carry-using instructions as close to each other as possible, so we can avoid
// storing the carry flag.
// Compare pass: bubble compare instructions next to branches, so they can be merged.
const int start = reverse ? instructions - 1 : 0;
const int end = reverse ? 0 : instructions - 1;
const int increment = reverse ? -1 : 1;
int i = start;
int next = start;
bool go_backwards = false;
while (true)
{
// Instruction Reordering Pass
// Carry pass: bubble carry-using instructions as close to each other as possible, so we can
// avoid
// storing the carry flag.
// Compare pass: bubble compare instructions next to branches, so they can be merged.
bool swapped = false;
int increment = reverse ? -1 : 1;
int start = reverse ? instructions - 1 : 0;
int end = reverse ? 0 : instructions - 1;
for (int i = start; i != end; i += increment)
if (go_backwards)
{
CodeOp& a = code[i];
CodeOp& b = code[i + increment];
// Reorder integer compares, rlwinm., and carry-affecting ops
// (if we add more merged branch instructions, add them here!)
if ((type == ReorderType::CROR && isCror(a)) ||
(type == ReorderType::Carry && isCarryOp(a)) ||
(type == ReorderType::CMP && (isCmp(a) || a.outputCR[0])))
i -= increment;
go_backwards = false;
}
else
{
i = next;
next += increment;
}
if (i == end)
break;
CodeOp& a = code[i];
CodeOp& b = code[i + increment];
// Reorder integer compares, rlwinm., and carry-affecting ops
// (if we add more merged branch instructions, add them here!)
if ((type == ReorderType::CROR && isCror(a)) || (type == ReorderType::Carry && isCarryOp(a)) ||
(type == ReorderType::CMP && (isCmp(a) || a.outputCR[0])))
{
// once we're next to a carry instruction, don't move away!
if (type == ReorderType::Carry && i != start)
{
// once we're next to a carry instruction, don't move away!
if (type == ReorderType::Carry && i != start)
// if we read the CA flag, and the previous instruction sets it, don't move away.
if (!reverse && (a.opinfo->flags & FL_READ_CA) &&
(code[i - increment].opinfo->flags & FL_SET_CA))
{
// if we read the CA flag, and the previous instruction sets it, don't move away.
if (!reverse && (a.opinfo->flags & FL_READ_CA) &&
(code[i - increment].opinfo->flags & FL_SET_CA))
continue;
// if we set the CA flag, and the next instruction reads it, don't move away.
if (reverse && (a.opinfo->flags & FL_SET_CA) &&
(code[i - increment].opinfo->flags & FL_READ_CA))
continue;
continue;
}
if (CanSwapAdjacentOps(a, b))
// if we set the CA flag, and the next instruction reads it, don't move away.
if (reverse && (a.opinfo->flags & FL_SET_CA) &&
(code[i - increment].opinfo->flags & FL_READ_CA))
{
// Alright, let's bubble it!
std::swap(a, b);
swapped = true;
continue;
}
}
if (CanSwapAdjacentOps(a, b))
{
// Alright, let's bubble it!
std::swap(a, b);
if (i != start)
{
// Bubbling an instruction sometimes reveals another opportunity to bubble an instruction,
// so go one step backwards and check if we have such an opportunity.
go_backwards = true;
}
}
}
if (!swapped)
return;
}
}