dave/openttd
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

VarAction2: Detect equality comparisons

Browse Source 
Remove redundant equality with 0 comparison before ternary
This commit is contained in:
Jonathan G Rennison
2022-05-25 02:23:25 +01:00
parent 7283825638
commit 012d73ef34
3 changed files with 31 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
src/newgrf.cpp
View File

@@ -5666,6 +5666,15 @@ static void NewSpriteGroup(ByteReader *buf)
if (adjust.and_mask <= 1) inference = VA2AIF_SIGNED_NON_NEGATIVE | VA2AIF_ONE_OR_ZERO;
break;
case DSGA_OP_AND:
if ((prev_inference & VA2AIF_SIGNED_NON_NEGATIVE) && adjust.variable == 0x1A && adjust.shift_num == 0 && adjust.and_mask == 1) {
DeterministicSpriteGroupAdjust &prev = group->adjusts[group->adjusts.size() - 2];
if (prev.operation == DSGA_OP_SCMP || prev.operation == DSGA_OP_UCMP) {
prev.operation = DSGA_OP_EQ;
group->adjusts.pop_back();
inference = VA2AIF_SIGNED_NON_NEGATIVE | VA2AIF_ONE_OR_ZERO;
break;
}
}
if (adjust.and_mask <= 1) {
inference = VA2AIF_SIGNED_NON_NEGATIVE | VA2AIF_ONE_OR_ZERO;
} else if ((adjust.and_mask & (1 << ((varsize * 8) - 1))) == 0) {
@@ -5700,6 +5709,17 @@ static void NewSpriteGroup(ByteReader *buf)
}
break;
}
if (group->adjusts.size() > 1) {
/* Remove redundant comparison with 0 if applicable */
const DeterministicSpriteGroupAdjust &prev = group->adjusts[group->adjusts.size() - 2];
if (prev.type == DSGA_TYPE_NONE && prev.operation == DSGA_OP_EQ && prev.variable == 0x1A && prev.shift_num == 0 && prev.and_mask == 0) {
DeterministicSpriteGroupAdjust current = group->adjusts.back();
group->adjusts.pop_back();
group->adjusts.pop_back();
std::swap(current.and_mask, current.add_val);
group->adjusts.push_back(current);
}
}
inference = VA2AIF_PREV_TERNARY;
}
break;

11
src/newgrf_spritegroup.cpp
View File

@@ -183,6 +183,7 @@ static U EvalAdjustT(const DeterministicSpriteGroupAdjust &adjust, ScopeResolver
case DSGA_OP_SHR: return (uint32)(U)last_value >> ((U)value & 0x1F);
case DSGA_OP_SAR: return (int32)(S)last_value >> ((U)value & 0x1F);
case DSGA_OP_TERNARY: return (last_value != 0) ? value : adjust.add_val;
case DSGA_OP_EQ: return (last_value == value) ? 1 : 0;
default: return value;
}
}
@@ -562,6 +563,14 @@ static const char *_sg_size_names[] {
"DWORD",
};
static const char *GetAdjustOperationName(DeterministicSpriteGroupAdjustOperation operation)
{
if (operation < DSGA_OP_END) return _dsg_op_names[operation];
if (operation == DSGA_OP_TERNARY) return "TERNARY";
if (operation == DSGA_OP_EQ) return "EQ";
return "???";
}
void SpriteGroupDumper::DumpSpriteGroup(const SpriteGroup *sg, int padding, uint flags)
{
if (sg == nullptr) {
@@ -634,7 +643,7 @@ void SpriteGroupDumper::DumpSpriteGroup(const SpriteGroup *sg, int padding, uint
case DSGA_TYPE_MOD: p += seprintf(p, lastof(this->buffer), ", add: %X, mod: %X", adjust.add_val, adjust.divmod_val); break;
case DSGA_TYPE_NONE: break;
}
p += seprintf(p, lastof(this->buffer), ", op: %X (%s)", adjust.operation, adjust.operation < DSGA_OP_END ? _dsg_op_names[adjust.operation] : "???");
p += seprintf(p, lastof(this->buffer), ", op: %X (%s)", adjust.operation, GetAdjustOperationName(adjust.operation));
this->print();
}
if (dsg->calculated_result) {

1
src/newgrf_spritegroup.h
View File

@@ -163,6 +163,7 @@ enum DeterministicSpriteGroupAdjustOperation {
DSGA_OP_END,
DSGA_OP_TERNARY = 0x80, ///< a == 0 ? b : c,
DSGA_OP_EQ, ///< a == b ? 1 : 0,
DSGA_OP_SPECIAL_END,
};