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[JAEGER] Enhanced constant-folding of rel ops.

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This commit is contained in:
David Anderson
2010-05-31 03:19:46 -07:00
parent 98ea5d08f5
commit 10ca7030e2
6 changed files with 114 additions and 30 deletions
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75
js/src/methodjit/Compiler.cpp
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@@ -296,38 +296,79 @@ mjit::Compiler::generateMethod()
BEGIN_CASE(JSOP_GT)
BEGIN_CASE(JSOP_GE)
{
/* These advance the PC automatically. */
JSOp fused = JSOp(PC[JSOP_GE_LENGTH]);
if (fused != JSOP_IFEQ && fused != JSOP_IFNE)
/* Detect fusions. */
jsbytecode *next = &PC[JSOP_GE_LENGTH];
JSOp fused = JSOp(*next);
if ((fused != JSOP_IFEQ && fused != JSOP_IFNE) || analysis[next].nincoming)
fused = JSOP_NOP;
jsbytecode *target = &PC[JSOP_GE_LENGTH] + GET_JUMP_OFFSET(&PC[JSOP_GE_LENGTH]);
/* Get jump target, if any. */
jsbytecode *target = NULL;
if (fused != JSOP_NOP)
target = next + GET_JUMP_OFFSET(next);
FrameEntry *rhs = frame.peek(-1);
FrameEntry *lhs = frame.peek(-2);
/* Check for easy cases that the parser does not constant fold. */
if (lhs->isConstant() && rhs->isConstant() &&
lhs->getValue().isPrimitive() && rhs->getValue().isPrimitive())
{
if (lhs->isConstant() && rhs->isConstant()) {
/* Primitives can be trivially constant folded. */
const Value &lv = lhs->getValue();
const Value &rv = rhs->getValue();
bool result = compareTwoValues(cx, op, lv, rv);
if (lv.isPrimitive() && rv.isPrimitive()) {
bool result = compareTwoValues(cx, op, lv, rv);
frame.pop();
frame.pop();
frame.pop();
frame.pop();
if (fused == JSOP_NOP) {
frame.push(Value(BooleanTag(result)));
if (!target) {
frame.push(Value(BooleanTag(result)));
} else {
if (fused == JSOP_IFEQ)
result = !result;
/* Branch is never taken, don't bother doing anything. */
if (result) {
frame.forgetEverything();
Jump j = masm.jump();
jumpInScript(j, target);
}
}
} else {
if (fused == JSOP_IFEQ)
result = !result;
prepareStubCall();
BoolStub stub = NULL;
switch (op) {
case JSOP_LT:
stub = stubs::LessThan;
break;
case JSOP_LE:
stub = stubs::LessEqual;
break;
case JSOP_GT:
stub = stubs::GreaterThan;
break;
case JSOP_GE:
stub = stubs::GreaterEqual;
break;
default:
JS_NOT_REACHED("WAT");
break;
}
stubCall(stub, Uses(2), Defs(0));
frame.pop();
frame.pop();
/* Branch is never taken, don't bother doing anything. */
if (result) {
if (!target) {
frame.takeReg(Registers::ReturnReg);
frame.pushTypedPayload(JSVAL_MASK32_BOOLEAN, Registers::ReturnReg);
} else {
frame.forgetEverything();
Jump j = masm.jump();
Assembler::Condition cond = (fused == JSOP_IFEQ)
? Assembler::Zero
: Assembler::NonZero;
Jump j = masm.branchTest32(cond, Registers::ReturnReg,
Registers::ReturnReg);
jumpInScript(j, target);
}
}