Fixing const propagated DID_CARRY.

This commit is contained in:
Ben Vanik 2014-05-30 20:09:00 -07:00
parent d65b5801f8
commit 0b42c72ec5
5 changed files with 74 additions and 10 deletions

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@ -2329,24 +2329,28 @@ EMITTER_ASSOCIATIVE_COMPARE_FLT_XX(UGE, setae);
// https://code.google.com/p/corkami/wiki/x86oddities
EMITTER(DID_CARRY_I8, MATCH(I<OPCODE_DID_CARRY, I8<>, I8<>>)) {
static void Emit(X64Emitter& e, const EmitArgType& i) {
XEASSERT(!i.src1.is_constant);
e.LoadEflags();
e.setc(i.dest);
}
};
EMITTER(DID_CARRY_I16, MATCH(I<OPCODE_DID_CARRY, I8<>, I16<>>)) {
static void Emit(X64Emitter& e, const EmitArgType& i) {
XEASSERT(!i.src1.is_constant);
e.LoadEflags();
e.setc(i.dest);
}
};
EMITTER(DID_CARRY_I32, MATCH(I<OPCODE_DID_CARRY, I8<>, I32<>>)) {
static void Emit(X64Emitter& e, const EmitArgType& i) {
XEASSERT(!i.src1.is_constant);
e.LoadEflags();
e.setc(i.dest);
}
};
EMITTER(DID_CARRY_I64, MATCH(I<OPCODE_DID_CARRY, I8<>, I64<>>)) {
static void Emit(X64Emitter& e, const EmitArgType& i) {
XEASSERT(!i.src1.is_constant);
e.LoadEflags();
e.setc(i.dest);
}
@ -4414,8 +4418,8 @@ EMITTER(EXTRACT_I8, MATCH(I<OPCODE_EXTRACT, I8<>, V128<>, I8<>>)) {
} else {
XEASSERTALWAYS();
// TODO(benvanik): try out hlide's version:
// mov eax, 0x80808080
// mov al, i.src2
// mov eax, 0x80808003
// xor al, i.src2.cvt8()
// vmovd xmm0, eax
// vpshufb xmm0, i.src1, xmm0
// vmovd i.dest.reg().cvt32(), xmm0
@ -4430,6 +4434,7 @@ EMITTER(EXTRACT_I16, MATCH(I<OPCODE_EXTRACT, I16<>, V128<>, I8<>>)) {
// TODO(benvanik): try out hlide's version:
// xor eax, eax
// mov al, i.src2 // eax = [i, 0, 0, 0]
// xor eax, 0x80800203
// imul eax, eax, 0x00000202 // [i*2, i*2, 0, 0] supposedly that 0<= i < 8
// add eax,0x80800100 // [i*2+0b00, i*2+0b01, 0x80, 0x80]
// vmovd xmm0, eax
@ -4454,7 +4459,7 @@ EMITTER(EXTRACT_I32, MATCH(I<OPCODE_EXTRACT, I32<>, V128<>, I8<>>)) {
// xor eax, eax
// mov al, i.src2 // eax = [i, 0, 0, 0]
// imul eax, eax, 0x04040404 // [i*4, i*4, i*4, i*4] supposedly that 0<= i < 4
// add eax,0x03020100 // [i*4+0b00, i*4+0b01, i*4+0b10, i*4+0b11]
// xor/add eax, 0x00010203 // [i*4+0b00, i*4+0b01, i*4+0b10, i*4+0b11]
// vmovd xmm0, eax
// vpshufb xmm0, i.src1, xmm0
// vmovd i.dest.reg().cvt32(), xmm0

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@ -43,6 +43,14 @@ int ConstantPropagationPass::Run(HIRBuilder* builder) {
// v1 = add 1000, 1000
// store_context +200, 2000
// A DCE run after this should clean up any of the values no longer needed.
//
// Special care needs to be taken with paired instructions. For example,
// DID_CARRY needs to be set as a constant:
// v1 = sub.2 20, 1
// v2 = did_carry v1
// should become:
// v1 = 19
// v2 = 0
Block* block = builder->first_block();
while (block) {
@ -252,19 +260,41 @@ int ConstantPropagationPass::Run(HIRBuilder* builder) {
}
break;
case OPCODE_DID_CARRY:
XEASSERT(!i->src1.value->IsConstant());
break;
case OPCODE_DID_OVERFLOW:
XEASSERT(!i->src1.value->IsConstant());
break;
case OPCODE_DID_SATURATE:
XEASSERT(!i->src1.value->IsConstant());
break;
case OPCODE_ADD:
if (i->src1.value->IsConstant() && i->src2.value->IsConstant()) {
v->set_from(i->src1.value);
v->Add(i->src2.value);
bool did_carry = v->Add(i->src2.value);
bool propagate_carry = !!(i->flags & ARITHMETIC_SET_CARRY);
i->Remove();
// If carry is set find the DID_CARRY and fix it.
if (propagate_carry) {
PropagateCarry(v, did_carry);
}
}
break;
// TODO(benvanik): ADD_CARRY
// TODO(benvanik): ADD_CARRY (w/ ARITHMETIC_SET_CARRY)
case OPCODE_SUB:
if (i->src1.value->IsConstant() && i->src2.value->IsConstant()) {
v->set_from(i->src1.value);
v->Sub(i->src2.value);
bool did_carry = v->Sub(i->src2.value);
bool propagate_carry = !!(i->flags & ARITHMETIC_SET_CARRY);
i->Remove();
// If carry is set find the DID_CARRY and fix it.
if (propagate_carry) {
PropagateCarry(v, did_carry);
}
}
break;
case OPCODE_MUL:
@ -393,3 +423,16 @@ int ConstantPropagationPass::Run(HIRBuilder* builder) {
return 0;
}
void ConstantPropagationPass::PropagateCarry(hir::Value* v, bool did_carry) {
auto next = v->use_head;
while (next) {
auto use = next;
next = use->next;
if (use->instr->opcode == &OPCODE_DID_CARRY_info) {
// Replace carry value.
use->instr->dest->set_constant(did_carry ? 1 : 0);
use->instr->Remove();
}
}
}

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@ -26,6 +26,7 @@ public:
virtual int Run(hir::HIRBuilder* builder);
private:
void PropagateCarry(hir::Value* v, bool did_carry);
};

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@ -187,19 +187,26 @@ void Value::Round(RoundMode round_mode) {
XEASSERTALWAYS();
}
void Value::Add(Value* other) {
bool Value::Add(Value* other) {
#define CHECK_DID_CARRY(v1, v2) (((uint64_t)v2) > ~((uint64_t)v1))
#define ADD_DID_CARRY(a, b) CHECK_DID_CARRY(a, b)
XEASSERT(type == other->type);
bool did_carry = false;
switch (type) {
case INT8_TYPE:
did_carry = ADD_DID_CARRY(constant.i8, other->constant.i8);
constant.i8 += other->constant.i8;
break;
case INT16_TYPE:
did_carry = ADD_DID_CARRY(constant.i16, other->constant.i16);
constant.i16 += other->constant.i16;
break;
case INT32_TYPE:
did_carry = ADD_DID_CARRY(constant.i32, other->constant.i32);
constant.i32 += other->constant.i32;
break;
case INT64_TYPE:
did_carry = ADD_DID_CARRY(constant.i64, other->constant.i64);
constant.i64 += other->constant.i64;
break;
case FLOAT32_TYPE:
@ -212,21 +219,28 @@ void Value::Add(Value* other) {
XEASSERTALWAYS();
break;
}
return did_carry;
}
void Value::Sub(Value* other) {
bool Value::Sub(Value* other) {
#define SUB_DID_CARRY(a, b) (b > a)
XEASSERT(type == other->type);
bool did_carry = false;
switch (type) {
case INT8_TYPE:
did_carry = SUB_DID_CARRY(constant.i8, other->constant.i8);
constant.i8 -= other->constant.i8;
break;
case INT16_TYPE:
did_carry = SUB_DID_CARRY(constant.i16, other->constant.i16);
constant.i16 -= other->constant.i16;
break;
case INT32_TYPE:
did_carry = SUB_DID_CARRY(constant.i32, other->constant.i32);
constant.i32 -= other->constant.i32;
break;
case INT64_TYPE:
did_carry = SUB_DID_CARRY(constant.i64, other->constant.i64);
constant.i64 -= other->constant.i64;
break;
case FLOAT32_TYPE:
@ -239,6 +253,7 @@ void Value::Sub(Value* other) {
XEASSERTALWAYS();
break;
}
return did_carry;
}
void Value::Mul(Value* other) {

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@ -375,8 +375,8 @@ public:
void Truncate(TypeName target_type);
void Convert(TypeName target_type, RoundMode round_mode);
void Round(RoundMode round_mode);
void Add(Value* other);
void Sub(Value* other);
bool Add(Value* other);
bool Sub(Value* other);
void Mul(Value* other);
void Div(Value* other);
static void MulAdd(Value* dest, Value* value1, Value* value2, Value* value3);