Reuse flag results in OPCODE_BRANCH_TRUE codegen if the preceding instruction was a comparison that already set the cpu flags

This commit is contained in:
chss95cs@gmail.com 2019-08-03 13:44:16 -07:00 committed by illusion
parent e21cc2ddae
commit b4b0cf3421
1 changed files with 79 additions and 13 deletions

View File

@ -20,7 +20,59 @@ namespace backend {
namespace x64 {
volatile int anchor_control = 0;
template <typename T>
static void EmitFusedBranch(X64Emitter& e, const T& i) {
bool valid = i.instr->prev && i.instr->prev->dest == i.src1.value;
auto opcode = valid ? i.instr->prev->opcode->num : -1;
if (valid) {
auto name = i.src2.value->name;
switch (opcode) {
case OPCODE_IS_TRUE:
e.jnz(name, e.T_NEAR);
break;
case OPCODE_IS_FALSE:
e.jz(name, e.T_NEAR);
break;
case OPCODE_COMPARE_EQ:
e.je(name, e.T_NEAR);
break;
case OPCODE_COMPARE_NE:
e.jne(name, e.T_NEAR);
break;
case OPCODE_COMPARE_SLT:
e.jl(name, e.T_NEAR);
break;
case OPCODE_COMPARE_SLE:
e.jle(name, e.T_NEAR);
break;
case OPCODE_COMPARE_SGT:
e.jg(name, e.T_NEAR);
break;
case OPCODE_COMPARE_SGE:
e.jge(name, e.T_NEAR);
break;
case OPCODE_COMPARE_ULT:
e.jb(name, e.T_NEAR);
break;
case OPCODE_COMPARE_ULE:
e.jbe(name, e.T_NEAR);
break;
case OPCODE_COMPARE_UGT:
e.ja(name, e.T_NEAR);
break;
case OPCODE_COMPARE_UGE:
e.jae(name, e.T_NEAR);
break;
default:
e.test(i.src1, i.src1);
e.jnz(name, e.T_NEAR);
break;
}
} else {
e.test(i.src1, i.src1);
e.jnz(i.src2.value->name, e.T_NEAR);
}
}
// ============================================================================
// OPCODE_DEBUG_BREAK
// ============================================================================
@ -450,43 +502,57 @@ EMITTER_OPCODE_TABLE(OPCODE_BRANCH, BRANCH);
struct BRANCH_TRUE_I8
: Sequence<BRANCH_TRUE_I8, I<OPCODE_BRANCH_TRUE, VoidOp, I8Op, LabelOp>> {
static void Emit(X64Emitter& e, const EmitArgType& i) {
e.test(i.src1, i.src1);
e.jnz(i.src2.value->name, e.T_NEAR);
EmitFusedBranch(e, i);
}
};
struct BRANCH_TRUE_I16
: Sequence<BRANCH_TRUE_I16, I<OPCODE_BRANCH_TRUE, VoidOp, I16Op, LabelOp>> {
static void Emit(X64Emitter& e, const EmitArgType& i) {
e.test(i.src1, i.src1);
e.jnz(i.src2.value->name, e.T_NEAR);
EmitFusedBranch(e, i);
}
};
struct BRANCH_TRUE_I32
: Sequence<BRANCH_TRUE_I32, I<OPCODE_BRANCH_TRUE, VoidOp, I32Op, LabelOp>> {
static void Emit(X64Emitter& e, const EmitArgType& i) {
e.test(i.src1, i.src1);
e.jnz(i.src2.value->name, e.T_NEAR);
EmitFusedBranch(e, i);
}
};
struct BRANCH_TRUE_I64
: Sequence<BRANCH_TRUE_I64, I<OPCODE_BRANCH_TRUE, VoidOp, I64Op, LabelOp>> {
static void Emit(X64Emitter& e, const EmitArgType& i) {
e.test(i.src1, i.src1);
e.jnz(i.src2.value->name, e.T_NEAR);
EmitFusedBranch(e, i);
}
};
struct BRANCH_TRUE_F32
: Sequence<BRANCH_TRUE_F32, I<OPCODE_BRANCH_TRUE, VoidOp, F32Op, LabelOp>> {
static void Emit(X64Emitter& e, const EmitArgType& i) {
e.vptest(i.src1, i.src1);
e.jnz(i.src2.value->name, e.T_NEAR);
if (i.instr->prev && i.instr->prev->opcode == &OPCODE_IS_TRUE_info &&
i.instr->prev->dest == i.src1.value) {
e.jnz(i.src2.value->name, e.T_NEAR);
} else if (i.instr->prev &&
i.instr->prev->opcode == &OPCODE_IS_FALSE_info &&
i.instr->prev->dest == i.src1.value) {
e.jz(i.src2.value->name, e.T_NEAR);
} else {
e.vptest(i.src1, i.src1);
e.jnz(i.src2.value->name, e.T_NEAR);
}
}
};
struct BRANCH_TRUE_F64
: Sequence<BRANCH_TRUE_F64, I<OPCODE_BRANCH_TRUE, VoidOp, F64Op, LabelOp>> {
static void Emit(X64Emitter& e, const EmitArgType& i) {
e.vptest(i.src1, i.src1);
e.jnz(i.src2.value->name, e.T_NEAR);
if (i.instr->prev && i.instr->prev->opcode == &OPCODE_IS_TRUE_info &&
i.instr->prev->dest == i.src1.value) {
e.jnz(i.src2.value->name, e.T_NEAR);
} else if (i.instr->prev &&
i.instr->prev->opcode == &OPCODE_IS_FALSE_info &&
i.instr->prev->dest == i.src1.value) {
e.jz(i.src2.value->name, e.T_NEAR);
} else {
e.vptest(i.src1, i.src1);
e.jnz(i.src2.value->name, e.T_NEAR);
}
}
};
EMITTER_OPCODE_TABLE(OPCODE_BRANCH_TRUE, BRANCH_TRUE_I8, BRANCH_TRUE_I16,