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[JAEGER] Constant fold LT,LE,GT,GE.

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This commit is contained in:
David Anderson
2010-05-31 02:17:05 -07:00
parent fbbe34f676
commit 98ea5d08f5
3 changed files with 106 additions and 0 deletions
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98
js/src/methodjit/Compiler.cpp
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@@ -38,6 +38,7 @@
*
* ***** END LICENSE BLOCK ***** */
#include "MethodJIT.h"
#include "jsnum.h"
#include "Compiler.h"
#include "StubCalls.h"
#include "assembler/jit/ExecutableAllocator.h"
@@ -290,6 +291,59 @@ mjit::Compiler::generateMethod()
}
END_CASE(JSOP_GOTO)
BEGIN_CASE(JSOP_LT)
BEGIN_CASE(JSOP_LE)
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)
fused = JSOP_NOP;
jsbytecode *target = &PC[JSOP_GE_LENGTH] + GET_JUMP_OFFSET(&PC[JSOP_GE_LENGTH]);
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())
{
/* Primitives can be trivially constant folded. */
const Value &lv = lhs->getValue();
const Value &rv = rhs->getValue();
bool result = compareTwoValues(cx, op, lv, rv);
frame.pop();
frame.pop();
if (fused == JSOP_NOP) {
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 {
/* Anything else should go through the fast path generator. */
jsop_relational(op, target, fused);
}
/* Advance PC manually. */
PC += JSOP_GE_LENGTH;
if (fused != JSOP_NOP)
PC += JSOP_IFNE_LENGTH;
break;
}
END_CASE(JSOP_GE)
BEGIN_CASE(JSOP_BITAND)
jsop_bitop(op);
END_CASE(JSOP_BITAND)
@@ -565,3 +619,47 @@ mjit::Compiler::restoreFrameRegs()
masm.loadPtr(FrameAddress(offsetof(VMFrame, fp)), Assembler::FpReg);
}
bool
mjit::Compiler::compareTwoValues(JSContext *cx, JSOp op, const Value &lhs, const Value &rhs)
{
JS_ASSERT(lhs.isPrimitive());
JS_ASSERT(rhs.isPrimitive());
if (lhs.isString() && rhs.isString()) {
int cmp = js_CompareStrings(lhs.asString(), rhs.asString());
switch (op) {
case JSOP_LT:
return cmp < 0;
case JSOP_LE:
return cmp <= 0;
case JSOP_GT:
return cmp > 0;
case JSOP_GE:
return cmp >= 0;
default:
JS_NOT_REACHED("NYI");
}
} else {
double ld, rd;
/* These should be infallible w/ primitives. */
ValueToNumber(cx, lhs, &ld);
ValueToNumber(cx, rhs, &rd);
switch(op) {
case JSOP_LT:
return ld < rd;
case JSOP_LE:
return ld <= rd;
case JSOP_GT:
return ld > rd;
case JSOP_GE:
return ld >= rd;
default:
JS_NOT_REACHED("NYI");
}
}
JS_NOT_REACHED("NYI");
return false;
}