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

VarAction2: Remove redundant temp store loads after stores

Browse Source
This commit is contained in:
Jonathan G Rennison
2022-05-25 19:17:15 +01:00
parent db5be4f92e
commit a21ae12c90
1 changed files with 31 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

35
src/newgrf.cpp
View File

@@ -5532,6 +5532,9 @@ enum VarAction2AdjustInferenceFlags {
VA2AIF_ONE_OR_ZERO = 0x02,
VA2AIF_PREV_TERNARY = 0x04,
VA2AIF_PREV_MASK_ADJUST = 0x08,
VA2AIF_PREV_STORE_TMP = 0x10,
VA2AIF_PREV_MASK = VA2AIF_PREV_TERNARY | VA2AIF_PREV_MASK_ADJUST | VA2AIF_PREV_STORE_TMP,
};
DECLARE_ENUM_AS_BIT_SET(VarAction2AdjustInferenceFlags)
@@ -5589,6 +5592,14 @@ static void NewSpriteGroup(ByteReader *buf)
case 2: group->size = DSG_SIZE_DWORD; varsize = 4; break;
}
auto get_sign_bit = [&]() -> uint32 {
return (1 << ((varsize * 8) - 1));
};
auto get_full_mask = [&]() -> uint32 {
return UINT_MAX >> ((4 - varsize) * 8);
};
VarAction2AdjustInferenceFlags inference = VA2AIF_NONE;
/* Loop through the var adjusts. Unfortunately we don't know how many we have
@@ -5647,7 +5658,7 @@ static void NewSpriteGroup(ByteReader *buf)
auto add_inferences_from_mask = [&](uint32 mask) {
if (mask == 1) {
inference |= VA2AIF_SIGNED_NON_NEGATIVE | VA2AIF_ONE_OR_ZERO;
} else if ((mask & (1 << ((varsize * 8) - 1))) == 0) {
} else if ((mask & get_sign_bit()) == 0) {
inference |= VA2AIF_SIGNED_NON_NEGATIVE;
}
};
@@ -5695,13 +5706,13 @@ static void NewSpriteGroup(ByteReader *buf)
}
if (adjust.and_mask <= 1) {
inference = VA2AIF_SIGNED_NON_NEGATIVE | VA2AIF_ONE_OR_ZERO;
} else if ((adjust.and_mask & (1 << ((varsize * 8) - 1))) == 0) {
} else if ((adjust.and_mask & get_sign_bit()) == 0) {
inference = VA2AIF_SIGNED_NON_NEGATIVE;
}
break;
case DSGA_OP_OR:
case DSGA_OP_XOR:
if (adjust.and_mask <= 1) inference = prev_inference & (~VA2AIF_PREV_TERNARY);
if (adjust.and_mask <= 1) inference = prev_inference & (~VA2AIF_PREV_MASK);
break;
case DSGA_OP_MUL: {
if ((prev_inference & VA2AIF_ONE_OR_ZERO) && adjust.variable == 0x1A && adjust.shift_num == 0) {
@@ -5753,14 +5764,30 @@ static void NewSpriteGroup(ByteReader *buf)
case DSGA_OP_SCMP:
inference = VA2AIF_SIGNED_NON_NEGATIVE;
/* Convert to UCMP if possible to make other analysis operations easier */
if ((prev_inference & VA2AIF_SIGNED_NON_NEGATIVE) && adjust.variable == 0x1A && adjust.shift_num == 0 && (adjust.and_mask & (1 << ((varsize * 8) - 1))) == 0) {
if ((prev_inference & VA2AIF_SIGNED_NON_NEGATIVE) && adjust.variable == 0x1A && adjust.shift_num == 0 && (adjust.and_mask & get_sign_bit()) == 0) {
adjust.operation = DSGA_OP_UCMP;
}
break;
case DSGA_OP_UCMP:
inference = VA2AIF_SIGNED_NON_NEGATIVE;
break;
case DSGA_OP_STOP:
inference = prev_inference & (~VA2AIF_PREV_MASK);
break;
case DSGA_OP_STO:
inference = prev_inference & (~VA2AIF_PREV_MASK);
if (adjust.variable == 0x1A && adjust.shift_num == 0) inference |= VA2AIF_PREV_STORE_TMP;
break;
case DSGA_OP_RST:
if ((prev_inference & VA2AIF_PREV_STORE_TMP) && adjust.variable == 0x7D && adjust.shift_num == 0 && adjust.and_mask == get_full_mask()) {
const DeterministicSpriteGroupAdjust &prev = group->adjusts[group->adjusts.size() - 2];
if (prev.type == DSGA_TYPE_NONE && prev.operation == DSGA_OP_STO && prev.variable == 0x1A && prev.shift_num == 0 && prev.and_mask == adjust.parameter) {
/* Redundant load from temp store after store to temp store */
group->adjusts.pop_back();
inference = prev_inference;
break;
}
}
add_inferences_from_mask(adjust.and_mask);
inference |= VA2AIF_PREV_MASK_ADJUST;
if ((prev_inference & VA2AIF_PREV_MASK_ADJUST) && adjust.variable == 0x7B) {