JDK14/Java14源码在线阅读
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#include "precompiled.hpp"
#include "memory/allocation.inline.hpp"
#include "opto/addnode.hpp"
#include "opto/connode.hpp"
#include "opto/convertnode.hpp"
#include "opto/divnode.hpp"
#include "opto/machnode.hpp"
#include "opto/movenode.hpp"
#include "opto/matcher.hpp"
#include "opto/mulnode.hpp"
#include "opto/phaseX.hpp"
#include "opto/subnode.hpp"
// Portions of code courtesy of Clifford Click
// Optimization - Graph Style
#include <math.h>
//----------------------magic_int_divide_constants-----------------------------
// Compute magic multiplier and shift constant for converting a 32 bit divide
// by constant into a multiply/shift/add series. Return false if calculations
// fail.
//
// Borrowed almost verbatim from Hacker's Delight by Henry S. Warren, Jr. with
// minor type name and parameter changes.
static bool magic_int_divide_constants(jint d, jint &M, jint &s) {
int32_t p;
uint32_t ad, anc, delta, q1, r1, q2, r2, t;
const uint32_t two31 = 0x80000000L; // 2**31.
ad = ABS(d);
if (d == 0 || d == 1) return false;
t = two31 + ((uint32_t)d >> 31);
anc = t - 1 - t%ad; // Absolute value of nc.
p = 31; // Init. p.
q1 = two31/anc; // Init. q1 = 2**p/|nc|.
r1 = two31 - q1*anc; // Init. r1 = rem(2**p, |nc|).
q2 = two31/ad; // Init. q2 = 2**p/|d|.
r2 = two31 - q2*ad; // Init. r2 = rem(2**p, |d|).
do {
p = p + 1;
q1 = 2*q1; // Update q1 = 2**p/|nc|.
r1 = 2*r1; // Update r1 = rem(2**p, |nc|).
if (r1 >= anc) { // (Must be an unsigned
q1 = q1 + 1; // comparison here).
r1 = r1 - anc;
}
q2 = 2*q2; // Update q2 = 2**p/|d|.
r2 = 2*r2; // Update r2 = rem(2**p, |d|).
if (r2 >= ad) { // (Must be an unsigned
q2 = q2 + 1; // comparison here).
r2 = r2 - ad;
}
delta = ad - r2;
} while (q1 < delta || (q1 == delta && r1 == 0));
M = q2 + 1;
if (d < 0) M = -M; // Magic number and
s = p - 32; // shift amount to return.
return true;
}
//--------------------------transform_int_divide-------------------------------
// Convert a division by constant divisor into an alternate Ideal graph.
// Return NULL if no transformation occurs.
static Node *transform_int_divide( PhaseGVN *phase, Node *dividend, jint divisor ) {
// Check for invalid divisors
assert( divisor != 0 && divisor != min_jint,
"bad divisor for transforming to long multiply" );
bool d_pos = divisor >= 0;
jint d = d_pos ? divisor : -divisor;
const int N = 32;
// Result
Node *q = NULL;
if (d == 1) {
// division by +/- 1
if (!d_pos) {
// Just negate the value
q = new SubINode(phase->intcon(0), dividend);
}
} else if ( is_power_of_2(d) ) {
// division by +/- a power of 2
// See if we can simply do a shift without rounding
bool needs_rounding = true;
const Type *dt = phase->type(dividend);
const TypeInt *dti = dt->isa_int();
if (dti && dti->_lo >= 0) {
// we don't need to round a positive dividend
needs_rounding = false;
} else if( dividend->Opcode() == Op_AndI ) {
// An AND mask of sufficient size clears the low bits and
// I can avoid rounding.
const TypeInt *andconi_t = phase->type( dividend->in(2) )->isa_int();
if( andconi_t && andconi_t->is_con() ) {
jint andconi = andconi_t->get_con();
if( andconi < 0 && is_power_of_2(-andconi) && (-andconi) >= d ) {
if( (-andconi) == d ) // Remove AND if it clears bits which will be shifted
dividend = dividend->in(1);
needs_rounding = false;
}
}
}
// Add rounding to the shift to handle the sign bit
int l = log2_jint(d-1)+1;
if (needs_rounding) {
// Divide-by-power-of-2 can be made into a shift, but you have to do
// more math for the rounding. You need to add 0 for positive
// numbers, and "i-1" for negative numbers. Example: i=4, so the
// shift is by 2. You need to add 3 to negative dividends and 0 to
// positive ones. So (-7+3)>>2 becomes -1, (-4+3)>>2 becomes -1,
// (-2+3)>>2 becomes 0, etc.
// Compute 0 or -1, based on sign bit
Node *sign = phase->transform(new RShiftINode(dividend, phase->intcon(N - 1)));
// Mask sign bit to the low sign bits
Node *round = phase->transform(new URShiftINode(sign, phase->intcon(N - l)));
// Round up before shifting
dividend = phase->transform(new AddINode(dividend, round));
}
// Shift for division
q = new RShiftINode(dividend, phase->intcon(l));
if (!d_pos) {
q = new SubINode(phase->intcon(0), phase->transform(q));
}
} else {
// Attempt the jint constant divide -> multiply transform found in
// "Division by Invariant Integers using Multiplication"
// by Granlund and Montgomery
// See also "Hacker's Delight", chapter 10 by Warren.
jint magic_const;
jint shift_const;
if (magic_int_divide_constants(d, magic_const, shift_const)) {
Node *magic = phase->longcon(magic_const);
Node *dividend_long = phase->transform(new ConvI2LNode(dividend));
// Compute the high half of the dividend x magic multiplication
Node *mul_hi = phase->transform(new MulLNode(dividend_long, magic));
if (magic_const < 0) {
mul_hi = phase->transform(new RShiftLNode(mul_hi, phase->intcon(N)));
mul_hi = phase->transform(new ConvL2INode(mul_hi));
// The magic multiplier is too large for a 32 bit constant. We've adjusted
// it down by 2^32, but have to add 1 dividend back in after the multiplication.
// This handles the "overflow" case described by Granlund and Montgomery.
mul_hi = phase->transform(new AddINode(dividend, mul_hi));
// Shift over the (adjusted) mulhi
if (shift_const != 0) {
mul_hi = phase->transform(new RShiftINode(mul_hi, phase->intcon(shift_const)));
}
} else {
// No add is required, we can merge the shifts together.
mul_hi = phase->transform(new RShiftLNode(mul_hi, phase->intcon(N + shift_const)));
mul_hi = phase->transform(new ConvL2INode(mul_hi));
}
// Get a 0 or -1 from the sign of the dividend.
Node *addend0 = mul_hi;
Node *addend1 = phase->transform(new RShiftINode(dividend, phase->intcon(N-1)));
// If the divisor is negative, swap the order of the input addends;
// this has the effect of negating the quotient.
if (!d_pos) {
Node *temp = addend0; addend0 = addend1; addend1 = temp;
}
// Adjust the final quotient by subtracting -1 (adding 1)
// from the mul_hi.
q = new SubINode(addend0, addend1);
}
}
return q;
}
//---------------------magic_long_divide_constants-----------------------------
// Compute magic multiplier and shift constant for converting a 64 bit divide
// by constant into a multiply/shift/add series. Return false if calculations
// fail.
//
// Borrowed almost verbatim from Hacker's Delight by Henry S. Warren, Jr. with
// minor type name and parameter changes. Adjusted to 64 bit word width.
static bool magic_long_divide_constants(jlong d, jlong &M, jint &s) {
int64_t p;
uint64_t ad, anc, delta, q1, r1, q2, r2, t;
const uint64_t two63 = UCONST64(0x8000000000000000); // 2**63.
ad = ABS(d);
if (d == 0 || d == 1) return false;
t = two63 + ((uint64_t)d >> 63);
anc = t - 1 - t%ad; // Absolute value of nc.
p = 63; // Init. p.
q1 = two63/anc; // Init. q1 = 2**p/|nc|.
r1 = two63 - q1*anc; // Init. r1 = rem(2**p, |nc|).
q2 = two63/ad; // Init. q2 = 2**p/|d|.
r2 = two63 - q2*ad; // Init. r2 = rem(2**p, |d|).
do {
p = p + 1;
q1 = 2*q1; // Update q1 = 2**p/|nc|.
r1 = 2*r1; // Update r1 = rem(2**p, |nc|).
if (r1 >= anc) { // (Must be an unsigned
q1 = q1 + 1; // comparison here).
r1 = r1 - anc;
}
q2 = 2*q2; // Update q2 = 2**p/|d|.
r2 = 2*r2; // Update r2 = rem(2**p, |d|).
if (r2 >= ad) { // (Must be an unsigned
q2 = q2 + 1; // comparison here).
r2 = r2 - ad;
}
delta = ad - r2;
} while (q1 < delta || (q1 == delta && r1 == 0));
M = q2 + 1;
if (d < 0) M = -M; // Magic number and
s = p - 64; // shift amount to return.
return true;
}
//---------------------long_by_long_mulhi--------------------------------------
// Generate ideal node graph for upper half of a 64 bit x 64 bit multiplication
static Node* long_by_long_mulhi(PhaseGVN* phase, Node* dividend, jlong magic_const) {
// If the architecture supports a 64x64 mulhi, there is
// no need to synthesize it in ideal nodes.
if (Matcher::has_match_rule(Op_MulHiL)) {
Node* v = phase->longcon(magic_const);
return new MulHiLNode(dividend, v);
}
// Taken from Hacker's Delight, Fig. 8-2. Multiply high signed.
// (http://www.hackersdelight.org/HDcode/mulhs.c)
//
// int mulhs(int u, int v) {
// unsigned u0, v0, w0;
// int u1, v1, w1, w2, t;
//
// u0 = u & 0xFFFF; u1 = u >> 16;
// v0 = v & 0xFFFF; v1 = v >> 16;
// w0 = u0*v0;
// t = u1*v0 + (w0 >> 16);
// w1 = t & 0xFFFF;
// w2 = t >> 16;
// w1 = u0*v1 + w1;
// return u1*v1 + w2 + (w1 >> 16);
// }
//
// Note: The version above is for 32x32 multiplications, while the
// following inline comments are adapted to 64x64.
const int N = 64;
// Dummy node to keep intermediate nodes alive during construction
Node* hook = new Node(4);
// u0 = u & 0xFFFFFFFF; u1 = u >> 32;
Node* u0 = phase->transform(new AndLNode(dividend, phase->longcon(0xFFFFFFFF)));
Node* u1 = phase->transform(new RShiftLNode(dividend, phase->intcon(N / 2)));
hook->init_req(0, u0);
hook->init_req(1, u1);
// v0 = v & 0xFFFFFFFF; v1 = v >> 32;
Node* v0 = phase->longcon(magic_const & 0xFFFFFFFF);
Node* v1 = phase->longcon(magic_const >> (N / 2));
// w0 = u0*v0;
Node* w0 = phase->transform(new MulLNode(u0, v0));
// t = u1*v0 + (w0 >> 32);
Node* u1v0 = phase->transform(new MulLNode(u1, v0));
Node* temp = phase->transform(new URShiftLNode(w0, phase->intcon(N / 2)));
Node* t = phase->transform(new AddLNode(u1v0, temp));
hook->init_req(2, t);
// w1 = t & 0xFFFFFFFF;
Node* w1 = phase->transform(new AndLNode(t, phase->longcon(0xFFFFFFFF)));
hook->init_req(3, w1);
// w2 = t >> 32;
Node* w2 = phase->transform(new RShiftLNode(t, phase->intcon(N / 2)));
// w1 = u0*v1 + w1;
Node* u0v1 = phase->transform(new MulLNode(u0, v1));
w1 = phase->transform(new AddLNode(u0v1, w1));
// return u1*v1 + w2 + (w1 >> 32);
Node* u1v1 = phase->transform(new MulLNode(u1, v1));
Node* temp1 = phase->transform(new AddLNode(u1v1, w2));
Node* temp2 = phase->transform(new RShiftLNode(w1, phase->intcon(N / 2)));
// Remove the bogus extra edges used to keep things alive
PhaseIterGVN* igvn = phase->is_IterGVN();
if (igvn != NULL) {
igvn->remove_dead_node(hook);
} else {
for (int i = 0; i < 4; i++) {
hook->set_req(i, NULL);
}
}
return new AddLNode(temp1, temp2);
}
//--------------------------transform_long_divide------------------------------
// Convert a division by constant divisor into an alternate Ideal graph.
// Return NULL if no transformation occurs.
static Node *transform_long_divide( PhaseGVN *phase, Node *dividend, jlong divisor ) {
// Check for invalid divisors
assert( divisor != 0L && divisor != min_jlong,
"bad divisor for transforming to long multiply" );
bool d_pos = divisor >= 0;
jlong d = d_pos ? divisor : -divisor;
const int N = 64;
// Result
Node *q = NULL;
if (d == 1) {
// division by +/- 1
if (!d_pos) {
// Just negate the value
q = new SubLNode(phase->longcon(0), dividend);
}
} else if ( is_power_of_2_long(d) ) {
// division by +/- a power of 2
// See if we can simply do a shift without rounding
bool needs_rounding = true;
const Type *dt = phase->type(dividend);
const TypeLong *dtl = dt->isa_long();
if (dtl && dtl->_lo > 0) {
// we don't need to round a positive dividend
needs_rounding = false;
} else if( dividend->Opcode() == Op_AndL ) {
// An AND mask of sufficient size clears the low bits and
// I can avoid rounding.
const TypeLong *andconl_t = phase->type( dividend->in(2) )->isa_long();
if( andconl_t && andconl_t->is_con() ) {
jlong andconl = andconl_t->get_con();
if( andconl < 0 && is_power_of_2_long(-andconl) && (-andconl) >= d ) {
if( (-andconl) == d ) // Remove AND if it clears bits which will be shifted
dividend = dividend->in(1);
needs_rounding = false;
}
}
}
// Add rounding to the shift to handle the sign bit
int l = log2_long(d-1)+1;
if (needs_rounding) {
// Divide-by-power-of-2 can be made into a shift, but you have to do
// more math for the rounding. You need to add 0 for positive
// numbers, and "i-1" for negative numbers. Example: i=4, so the
// shift is by 2. You need to add 3 to negative dividends and 0 to
// positive ones. So (-7+3)>>2 becomes -1, (-4+3)>>2 becomes -1,
// (-2+3)>>2 becomes 0, etc.
// Compute 0 or -1, based on sign bit
Node *sign = phase->transform(new RShiftLNode(dividend, phase->intcon(N - 1)));
// Mask sign bit to the low sign bits
Node *round = phase->transform(new URShiftLNode(sign, phase->intcon(N - l)));
// Round up before shifting
dividend = phase->transform(new AddLNode(dividend, round));
}
// Shift for division
q = new RShiftLNode(dividend, phase->intcon(l));
if (!d_pos) {
q = new SubLNode(phase->longcon(0), phase->transform(q));
}
} else if ( !Matcher::use_asm_for_ldiv_by_con(d) ) { // Use hardware DIV instruction when
// it is faster than code generated below.
// Attempt the jlong constant divide -> multiply transform found in
// "Division by Invariant Integers using Multiplication"
// by Granlund and Montgomery
// See also "Hacker's Delight", chapter 10 by Warren.
jlong magic_const;
jint shift_const;
if (magic_long_divide_constants(d, magic_const, shift_const)) {
// Compute the high half of the dividend x magic multiplication
Node *mul_hi = phase->transform(long_by_long_mulhi(phase, dividend, magic_const));
// The high half of the 128-bit multiply is computed.
if (magic_const < 0) {
// The magic multiplier is too large for a 64 bit constant. We've adjusted
// it down by 2^64, but have to add 1 dividend back in after the multiplication.
// This handles the "overflow" case described by Granlund and Montgomery.
mul_hi = phase->transform(new AddLNode(dividend, mul_hi));
}
// Shift over the (adjusted) mulhi
if (shift_const != 0) {
mul_hi = phase->transform(new RShiftLNode(mul_hi, phase->intcon(shift_const)));
}
// Get a 0 or -1 from the sign of the dividend.
Node *addend0 = mul_hi;
Node *addend1 = phase->transform(new RShiftLNode(dividend, phase->intcon(N-1)));
// If the divisor is negative, swap the order of the input addends;
// this has the effect of negating the quotient.
if (!d_pos) {
Node *temp = addend0; addend0 = addend1; addend1 = temp;
}
// Adjust the final quotient by subtracting -1 (adding 1)
// from the mul_hi.
q = new SubLNode(addend0, addend1);
}
}
return q;
}
//=============================================================================
//------------------------------Identity---------------------------------------
// If the divisor is 1, we are an identity on the dividend.
Node* DivINode::Identity(PhaseGVN* phase) {
return (phase->type( in(2) )->higher_equal(TypeInt::ONE)) ? in(1) : this;
}
//------------------------------Idealize---------------------------------------
// Divides can be changed to multiplies and/or shifts
Node *DivINode::Ideal(PhaseGVN *phase, bool can_reshape) {
if (in(0) && remove_dead_region(phase, can_reshape)) return this;
// Don't bother trying to transform a dead node
if( in(0) && in(0)->is_top() ) return NULL;
const Type *t = phase->type( in(2) );
if( t == TypeInt::ONE ) // Identity?
return NULL; // Skip it
const TypeInt *ti = t->isa_int();
if( !ti ) return NULL;
// Check for useless control input
// Check for excluding div-zero case
if (in(0) && (ti->_hi < 0 || ti->_lo > 0)) {
set_req(0, NULL); // Yank control input
return this;
}
if( !ti->is_con() ) return NULL;
jint i = ti->get_con(); // Get divisor
if (i == 0) return NULL; // Dividing by zero constant does not idealize
// Dividing by MININT does not optimize as a power-of-2 shift.
if( i == min_jint ) return NULL;
return transform_int_divide( phase, in(1), i );
}
//------------------------------Value------------------------------------------
// A DivINode divides its inputs. The third input is a Control input, used to
// prevent hoisting the divide above an unsafe test.
const Type* DivINode::Value(PhaseGVN* phase) const {
// Either input is TOP ==> the result is TOP
const Type *t1 = phase->type( in(1) );
const Type *t2 = phase->type( in(2) );
if( t1 == Type::TOP ) return Type::TOP;
if( t2 == Type::TOP ) return Type::TOP;
// x/x == 1 since we always generate the dynamic divisor check for 0.
if( phase->eqv( in(1), in(2) ) )
return TypeInt::ONE;
// Either input is BOTTOM ==> the result is the local BOTTOM
const Type *bot = bottom_type();
if( (t1 == bot) || (t2 == bot) ||
(t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
return bot;
// Divide the two numbers. We approximate.
// If divisor is a constant and not zero
const TypeInt *i1 = t1->is_int();
const TypeInt *i2 = t2->is_int();
int widen = MAX2(i1->_widen, i2->_widen);
if( i2->is_con() && i2->get_con() != 0 ) {
int32_t d = i2->get_con(); // Divisor
jint lo, hi;
if( d >= 0 ) {
lo = i1->_lo/d;
hi = i1->_hi/d;
} else {
if( d == -1 && i1->_lo == min_jint ) {
// 'min_jint/-1' throws arithmetic exception during compilation
lo = min_jint;
// do not support holes, 'hi' must go to either min_jint or max_jint:
// [min_jint, -10]/[-1,-1] ==> [min_jint] UNION [10,max_jint]
hi = i1->_hi == min_jint ? min_jint : max_jint;
} else {
lo = i1->_hi/d;
hi = i1->_lo/d;
}
}
return TypeInt::make(lo, hi, widen);
}
// If the dividend is a constant
if( i1->is_con() ) {
int32_t d = i1->get_con();
if( d < 0 ) {
if( d == min_jint ) {
// (-min_jint) == min_jint == (min_jint / -1)
return TypeInt::make(min_jint, max_jint/2 + 1, widen);
} else {
return TypeInt::make(d, -d, widen);
}
}
return TypeInt::make(-d, d, widen);
}
// Otherwise we give up all hope
return TypeInt::INT;
}
//=============================================================================
//------------------------------Identity---------------------------------------
// If the divisor is 1, we are an identity on the dividend.
Node* DivLNode::Identity(PhaseGVN* phase) {
return (phase->type( in(2) )->higher_equal(TypeLong::ONE)) ? in(1) : this;
}
//------------------------------Idealize---------------------------------------
// Dividing by a power of 2 is a shift.
Node *DivLNode::Ideal( PhaseGVN *phase, bool can_reshape) {
if (in(0) && remove_dead_region(phase, can_reshape)) return this;
// Don't bother trying to transform a dead node
if( in(0) && in(0)->is_top() ) return NULL;
const Type *t = phase->type( in(2) );
if( t == TypeLong::ONE ) // Identity?
return NULL; // Skip it
const TypeLong *tl = t->isa_long();
if( !tl ) return NULL;
// Check for useless control input
// Check for excluding div-zero case
if (in(0) && (tl->_hi < 0 || tl->_lo > 0)) {
set_req(0, NULL); // Yank control input
return this;
}
if( !tl->is_con() ) return NULL;
jlong l = tl->get_con(); // Get divisor
if (l == 0) return NULL; // Dividing by zero constant does not idealize
// Dividing by MINLONG does not optimize as a power-of-2 shift.
if( l == min_jlong ) return NULL;
return transform_long_divide( phase, in(1), l );
}
//------------------------------Value------------------------------------------
// A DivLNode divides its inputs. The third input is a Control input, used to
// prevent hoisting the divide above an unsafe test.
const Type* DivLNode::Value(PhaseGVN* phase) const {
// Either input is TOP ==> the result is TOP
const Type *t1 = phase->type( in(1) );
const Type *t2 = phase->type( in(2) );
if( t1 == Type::TOP ) return Type::TOP;
if( t2 == Type::TOP ) return Type::TOP;
// x/x == 1 since we always generate the dynamic divisor check for 0.
if( phase->eqv( in(1), in(2) ) )
return TypeLong::ONE;
// Either input is BOTTOM ==> the result is the local BOTTOM
const Type *bot = bottom_type();
if( (t1 == bot) || (t2 == bot) ||
(t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
return bot;
// Divide the two numbers. We approximate.
// If divisor is a constant and not zero
const TypeLong *i1 = t1->is_long();
const TypeLong *i2 = t2->is_long();
int widen = MAX2(i1->_widen, i2->_widen);
if( i2->is_con() && i2->get_con() != 0 ) {
jlong d = i2->get_con(); // Divisor
jlong lo, hi;
if( d >= 0 ) {
lo = i1->_lo/d;
hi = i1->_hi/d;
} else {
if( d == CONST64(-1) && i1->_lo == min_jlong ) {
// 'min_jlong/-1' throws arithmetic exception during compilation
lo = min_jlong;
// do not support holes, 'hi' must go to either min_jlong or max_jlong:
// [min_jlong, -10]/[-1,-1] ==> [min_jlong] UNION [10,max_jlong]
hi = i1->_hi == min_jlong ? min_jlong : max_jlong;
} else {
lo = i1->_hi/d;
hi = i1->_lo/d;
}
}
return TypeLong::make(lo, hi, widen);
}
// If the dividend is a constant
if( i1->is_con() ) {
jlong d = i1->get_con();
if( d < 0 ) {
if( d == min_jlong ) {
// (-min_jlong) == min_jlong == (min_jlong / -1)
return TypeLong::make(min_jlong, max_jlong/2 + 1, widen);
} else {
return TypeLong::make(d, -d, widen);
}
}
return TypeLong::make(-d, d, widen);
}
// Otherwise we give up all hope
return TypeLong::LONG;
}
//=============================================================================
//------------------------------Value------------------------------------------
// An DivFNode divides its inputs. The third input is a Control input, used to
// prevent hoisting the divide above an unsafe test.
const Type* DivFNode::Value(PhaseGVN* phase) const {
// Either input is TOP ==> the result is TOP
const Type *t1 = phase->type( in(1) );
const Type *t2 = phase->type( in(2) );
if( t1 == Type::TOP ) return Type::TOP;
if( t2 == Type::TOP ) return Type::TOP;
// Either input is BOTTOM ==> the result is the local BOTTOM
const Type *bot = bottom_type();
if( (t1 == bot) || (t2 == bot) ||
(t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
return bot;
// x/x == 1, we ignore 0/0.
// Note: if t1 and t2 are zero then result is NaN (JVMS page 213)
// Does not work for variables because of NaN's
if( phase->eqv( in(1), in(2) ) && t1->base() == Type::FloatCon)
if (!g_isnan(t1->getf()) && g_isfinite(t1->getf()) && t1->getf() != 0.0) // could be negative ZERO or NaN
return TypeF::ONE;
if( t2 == TypeF::ONE )
return t1;
// If divisor is a constant and not zero, divide them numbers
if( t1->base() == Type::FloatCon &&
t2->base() == Type::FloatCon &&
t2->getf() != 0.0 ) // could be negative zero
return TypeF::make( t1->getf()/t2->getf() );
// If the dividend is a constant zero
// Note: if t1 and t2 are zero then result is NaN (JVMS page 213)
// Test TypeF::ZERO is not sufficient as it could be negative zero
if( t1 == TypeF::ZERO && !g_isnan(t2->getf()) && t2->getf() != 0.0 )
return TypeF::ZERO;
// Otherwise we give up all hope
return Type::FLOAT;
}
//------------------------------isA_Copy---------------------------------------
// Dividing by self is 1.
// If the divisor is 1, we are an identity on the dividend.
Node* DivFNode::Identity(PhaseGVN* phase) {
return (phase->type( in(2) ) == TypeF::ONE) ? in(1) : this;
}
//------------------------------Idealize---------------------------------------
Node *DivFNode::Ideal(PhaseGVN *phase, bool can_reshape) {
if (in(0) && remove_dead_region(phase, can_reshape)) return this;
// Don't bother trying to transform a dead node
if( in(0) && in(0)->is_top() ) return NULL;
const Type *t2 = phase->type( in(2) );
if( t2 == TypeF::ONE ) // Identity?
return NULL; // Skip it
const TypeF *tf = t2->isa_float_constant();
if( !tf ) return NULL;
if( tf->base() != Type::FloatCon ) return NULL;
// Check for out of range values
if( tf->is_nan() || !tf->is_finite() ) return NULL;
// Get the value
float f = tf->getf();
int exp;
// Only for special case of dividing by a power of 2
if( frexp((double)f, &exp) != 0.5 ) return NULL;
// Limit the range of acceptable exponents
if( exp < -126 || exp > 126 ) return NULL;
// Compute the reciprocal
float reciprocal = ((float)1.0) / f;
assert( frexp((double)reciprocal, &exp) == 0.5, "reciprocal should be power of 2" );
// return multiplication by the reciprocal
return (new MulFNode(in(1), phase->makecon(TypeF::make(reciprocal))));
}
//=============================================================================
//------------------------------Value------------------------------------------
// An DivDNode divides its inputs. The third input is a Control input, used to
// prevent hoisting the divide above an unsafe test.
const Type* DivDNode::Value(PhaseGVN* phase) const {
// Either input is TOP ==> the result is TOP
const Type *t1 = phase->type( in(1) );
const Type *t2 = phase->type( in(2) );
if( t1 == Type::TOP ) return Type::TOP;
if( t2 == Type::TOP ) return Type::TOP;
// Either input is BOTTOM ==> the result is the local BOTTOM
const Type *bot = bottom_type();
if( (t1 == bot) || (t2 == bot) ||
(t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
return bot;
// x/x == 1, we ignore 0/0.
// Note: if t1 and t2 are zero then result is NaN (JVMS page 213)
// Does not work for variables because of NaN's
if( phase->eqv( in(1), in(2) ) && t1->base() == Type::DoubleCon)
if (!g_isnan(t1->getd()) && g_isfinite(t1->getd()) && t1->getd() != 0.0) // could be negative ZERO or NaN
return TypeD::ONE;
if( t2 == TypeD::ONE )
return t1;
#if defined(IA32)
if (!phase->C->method()->is_strict())
// Can't trust native compilers to properly fold strict double
// division with round-to-zero on this platform.
#endif
{
// If divisor is a constant and not zero, divide them numbers
if( t1->base() == Type::DoubleCon &&
t2->base() == Type::DoubleCon &&
t2->getd() != 0.0 ) // could be negative zero
return TypeD::make( t1->getd()/t2->getd() );
}
// If the dividend is a constant zero
// Note: if t1 and t2 are zero then result is NaN (JVMS page 213)
// Test TypeF::ZERO is not sufficient as it could be negative zero
if( t1 == TypeD::ZERO && !g_isnan(t2->getd()) && t2->getd() != 0.0 )
return TypeD::ZERO;
// Otherwise we give up all hope
return Type::DOUBLE;
}
//------------------------------isA_Copy---------------------------------------
// Dividing by self is 1.
// If the divisor is 1, we are an identity on the dividend.
Node* DivDNode::Identity(PhaseGVN* phase) {
return (phase->type( in(2) ) == TypeD::ONE) ? in(1) : this;
}
//------------------------------Idealize---------------------------------------
Node *DivDNode::Ideal(PhaseGVN *phase, bool can_reshape) {
if (in(0) && remove_dead_region(phase, can_reshape)) return this;
// Don't bother trying to transform a dead node
if( in(0) && in(0)->is_top() ) return NULL;
const Type *t2 = phase->type( in(2) );
if( t2 == TypeD::ONE ) // Identity?
return NULL; // Skip it
const TypeD *td = t2->isa_double_constant();
if( !td ) return NULL;
if( td->base() != Type::DoubleCon ) return NULL;
// Check for out of range values
if( td->is_nan() || !td->is_finite() ) return NULL;
// Get the value
double d = td->getd();
int exp;
// Only for special case of dividing by a power of 2
if( frexp(d, &exp) != 0.5 ) return NULL;
// Limit the range of acceptable exponents
if( exp < -1021 || exp > 1022 ) return NULL;
// Compute the reciprocal
double reciprocal = 1.0 / d;
assert( frexp(reciprocal, &exp) == 0.5, "reciprocal should be power of 2" );
// return multiplication by the reciprocal
return (new MulDNode(in(1), phase->makecon(TypeD::make(reciprocal))));
}
//=============================================================================
//------------------------------Idealize---------------------------------------
Node *ModINode::Ideal(PhaseGVN *phase, bool can_reshape) {
// Check for dead control input
if( in(0) && remove_dead_region(phase, can_reshape) ) return this;
// Don't bother trying to transform a dead node
if( in(0) && in(0)->is_top() ) return NULL;
// Get the modulus
const Type *t = phase->type( in(2) );
if( t == Type::TOP ) return NULL;
const TypeInt *ti = t->is_int();
// Check for useless control input
// Check for excluding mod-zero case
if (in(0) && (ti->_hi < 0 || ti->_lo > 0)) {
set_req(0, NULL); // Yank control input
return this;
}
// See if we are MOD'ing by 2^k or 2^k-1.
if( !ti->is_con() ) return NULL;
jint con = ti->get_con();
Node *hook = new Node(1);
// First, special check for modulo 2^k-1
if( con >= 0 && con < max_jint && is_power_of_2(con+1) ) {
uint k = exact_log2(con+1); // Extract k
// Basic algorithm by David Detlefs. See fastmod_int.java for gory details.
static int unroll_factor[] = { 999, 999, 29, 14, 9, 7, 5, 4, 4, 3, 3, 2, 2, 2, 2, 2, 1 /*past here we assume 1 forever*/};
int trip_count = 1;
if( k < ARRAY_SIZE(unroll_factor)) trip_count = unroll_factor[k];
// If the unroll factor is not too large, and if conditional moves are
// ok, then use this case
if( trip_count <= 5 && ConditionalMoveLimit != 0 ) {
Node *x = in(1); // Value being mod'd
Node *divisor = in(2); // Also is mask
hook->init_req(0, x); // Add a use to x to prevent him from dying
// Generate code to reduce X rapidly to nearly 2^k-1.
for( int i = 0; i < trip_count; i++ ) {
Node *xl = phase->transform( new AndINode(x,divisor) );
Node *xh = phase->transform( new RShiftINode(x,phase->intcon(k)) ); // Must be signed
x = phase->transform( new AddINode(xh,xl) );
hook->set_req(0, x);
}
// Generate sign-fixup code. Was original value positive?
// int hack_res = (i >= 0) ? divisor : 1;
Node *cmp1 = phase->transform( new CmpINode( in(1), phase->intcon(0) ) );
Node *bol1 = phase->transform( new BoolNode( cmp1, BoolTest::ge ) );
Node *cmov1= phase->transform( new CMoveINode(bol1, phase->intcon(1), divisor, TypeInt::POS) );
// if( x >= hack_res ) x -= divisor;
Node *sub = phase->transform( new SubINode( x, divisor ) );
Node *cmp2 = phase->transform( new CmpINode( x, cmov1 ) );
Node *bol2 = phase->transform( new BoolNode( cmp2, BoolTest::ge ) );
// Convention is to not transform the return value of an Ideal
// since Ideal is expected to return a modified 'this' or a new node.
Node *cmov2= new CMoveINode(bol2, x, sub, TypeInt::INT);
// cmov2 is now the mod
// Now remove the bogus extra edges used to keep things alive
if (can_reshape) {
phase->is_IterGVN()->remove_dead_node(hook);
} else {
hook->set_req(0, NULL); // Just yank bogus edge during Parse phase
}
return cmov2;
}
}
// Fell thru, the unroll case is not appropriate. Transform the modulo
// into a long multiply/int multiply/subtract case
// Cannot handle mod 0, and min_jint isn't handled by the transform
if( con == 0 || con == min_jint ) return NULL;
// Get the absolute value of the constant; at this point, we can use this
jint pos_con = (con >= 0) ? con : -con;
// integer Mod 1 is always 0
if( pos_con == 1 ) return new ConINode(TypeInt::ZERO);
int log2_con = -1;
// If this is a power of two, they maybe we can mask it
if( is_power_of_2(pos_con) ) {
log2_con = log2_intptr((intptr_t)pos_con);
const Type *dt = phase->type(in(1));
const TypeInt *dti = dt->isa_int();
// See if this can be masked, if the dividend is non-negative
if( dti && dti->_lo >= 0 )
return ( new AndINode( in(1), phase->intcon( pos_con-1 ) ) );
}
// Save in(1) so that it cannot be changed or deleted
hook->init_req(0, in(1));
// Divide using the transform from DivI to MulL
Node *result = transform_int_divide( phase, in(1), pos_con );
if (result != NULL) {
Node *divide = phase->transform(result);
// Re-multiply, using a shift if this is a power of two
Node *mult = NULL;
if( log2_con >= 0 )
mult = phase->transform( new LShiftINode( divide, phase->intcon( log2_con ) ) );
else
mult = phase->transform( new MulINode( divide, phase->intcon( pos_con ) ) );
// Finally, subtract the multiplied divided value from the original
result = new SubINode( in(1), mult );
}
// Now remove the bogus extra edges used to keep things alive
if (can_reshape) {
phase->is_IterGVN()->remove_dead_node(hook);
} else {
hook->set_req(0, NULL); // Just yank bogus edge during Parse phase
}
// return the value
return result;
}
//------------------------------Value------------------------------------------
const Type* ModINode::Value(PhaseGVN* phase) const {
// Either input is TOP ==> the result is TOP
const Type *t1 = phase->type( in(1) );
const Type *t2 = phase->type( in(2) );
if( t1 == Type::TOP ) return Type::TOP;
if( t2 == Type::TOP ) return Type::TOP;
// We always generate the dynamic check for 0.
// 0 MOD X is 0
if( t1 == TypeInt::ZERO ) return TypeInt::ZERO;
// X MOD X is 0
if( phase->eqv( in(1), in(2) ) ) return TypeInt::ZERO;
// Either input is BOTTOM ==> the result is the local BOTTOM
const Type *bot = bottom_type();
if( (t1 == bot) || (t2 == bot) ||
(t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
return bot;
const TypeInt *i1 = t1->is_int();
const TypeInt *i2 = t2->is_int();
if( !i1->is_con() || !i2->is_con() ) {
if( i1->_lo >= 0 && i2->_lo >= 0 )
return TypeInt::POS;
// If both numbers are not constants, we know little.
return TypeInt::INT;
}
// Mod by zero? Throw exception at runtime!
if( !i2->get_con() ) return TypeInt::POS;
// We must be modulo'ing 2 float constants.
// Check for min_jint % '-1', result is defined to be '0'.
if( i1->get_con() == min_jint && i2->get_con() == -1 )
return TypeInt::ZERO;
return TypeInt::make( i1->get_con() % i2->get_con() );
}
//=============================================================================
//------------------------------Idealize---------------------------------------
Node *ModLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
// Check for dead control input
if( in(0) && remove_dead_region(phase, can_reshape) ) return this;
// Don't bother trying to transform a dead node
if( in(0) && in(0)->is_top() ) return NULL;
// Get the modulus
const Type *t = phase->type( in(2) );
if( t == Type::TOP ) return NULL;
const TypeLong *tl = t->is_long();
// Check for useless control input
// Check for excluding mod-zero case
if (in(0) && (tl->_hi < 0 || tl->_lo > 0)) {
set_req(0, NULL); // Yank control input
return this;
}
// See if we are MOD'ing by 2^k or 2^k-1.
if( !tl->is_con() ) return NULL;
jlong con = tl->get_con();
Node *hook = new Node(1);
// Expand mod
if( con >= 0 && con < max_jlong && is_power_of_2_long(con+1) ) {
uint k = exact_log2_long(con+1); // Extract k
// Basic algorithm by David Detlefs. See fastmod_long.java for gory details.
// Used to help a popular random number generator which does a long-mod
// of 2^31-1 and shows up in SpecJBB and SciMark.
static int unroll_factor[] = { 999, 999, 61, 30, 20, 15, 12, 10, 8, 7, 6, 6, 5, 5, 4, 4, 4, 3, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1 /*past here we assume 1 forever*/};
int trip_count = 1;
if( k < ARRAY_SIZE(unroll_factor)) trip_count = unroll_factor[k];
// If the unroll factor is not too large, and if conditional moves are
// ok, then use this case
if( trip_count <= 5 && ConditionalMoveLimit != 0 ) {
Node *x = in(1); // Value being mod'd
Node *divisor = in(2); // Also is mask
hook->init_req(0, x); // Add a use to x to prevent him from dying
// Generate code to reduce X rapidly to nearly 2^k-1.
for( int i = 0; i < trip_count; i++ ) {
Node *xl = phase->transform( new AndLNode(x,divisor) );
Node *xh = phase->transform( new RShiftLNode(x,phase->intcon(k)) ); // Must be signed
x = phase->transform( new AddLNode(xh,xl) );
hook->set_req(0, x); // Add a use to x to prevent him from dying
}
// Generate sign-fixup code. Was original value positive?
// long hack_res = (i >= 0) ? divisor : CONST64(1);
Node *cmp1 = phase->transform( new CmpLNode( in(1), phase->longcon(0) ) );
Node *bol1 = phase->transform( new BoolNode( cmp1, BoolTest::ge ) );
Node *cmov1= phase->transform( new CMoveLNode(bol1, phase->longcon(1), divisor, TypeLong::LONG) );
// if( x >= hack_res ) x -= divisor;
Node *sub = phase->transform( new SubLNode( x, divisor ) );
Node *cmp2 = phase->transform( new CmpLNode( x, cmov1 ) );
Node *bol2 = phase->transform( new BoolNode( cmp2, BoolTest::ge ) );
// Convention is to not transform the return value of an Ideal
// since Ideal is expected to return a modified 'this' or a new node.
Node *cmov2= new CMoveLNode(bol2, x, sub, TypeLong::LONG);
// cmov2 is now the mod
// Now remove the bogus extra edges used to keep things alive
if (can_reshape) {
phase->is_IterGVN()->remove_dead_node(hook);
} else {
hook->set_req(0, NULL); // Just yank bogus edge during Parse phase
}
return cmov2;
}
}
// Fell thru, the unroll case is not appropriate. Transform the modulo
// into a long multiply/int multiply/subtract case
// Cannot handle mod 0, and min_jlong isn't handled by the transform
if( con == 0 || con == min_jlong ) return NULL;
// Get the absolute value of the constant; at this point, we can use this
jlong pos_con = (con >= 0) ? con : -con;
// integer Mod 1 is always 0
if( pos_con == 1 ) return new ConLNode(TypeLong::ZERO);
int log2_con = -1;
// If this is a power of two, then maybe we can mask it
if( is_power_of_2_long(pos_con) ) {
log2_con = exact_log2_long(pos_con);
const Type *dt = phase->type(in(1));
const TypeLong *dtl = dt->isa_long();
// See if this can be masked, if the dividend is non-negative
if( dtl && dtl->_lo >= 0 )
return ( new AndLNode( in(1), phase->longcon( pos_con-1 ) ) );
}
// Save in(1) so that it cannot be changed or deleted
hook->init_req(0, in(1));
// Divide using the transform from DivL to MulL
Node *result = transform_long_divide( phase, in(1), pos_con );
if (result != NULL) {
Node *divide = phase->transform(result);
// Re-multiply, using a shift if this is a power of two
Node *mult = NULL;
if( log2_con >= 0 )
mult = phase->transform( new LShiftLNode( divide, phase->intcon( log2_con ) ) );
else
mult = phase->transform( new MulLNode( divide, phase->longcon( pos_con ) ) );
// Finally, subtract the multiplied divided value from the original
result = new SubLNode( in(1), mult );
}
// Now remove the bogus extra edges used to keep things alive
if (can_reshape) {
phase->is_IterGVN()->remove_dead_node(hook);
} else {
hook->set_req(0, NULL); // Just yank bogus edge during Parse phase
}
// return the value
return result;
}
//------------------------------Value------------------------------------------
const Type* ModLNode::Value(PhaseGVN* phase) const {
// Either input is TOP ==> the result is TOP
const Type *t1 = phase->type( in(1) );
const Type *t2 = phase->type( in(2) );
if( t1 == Type::TOP ) return Type::TOP;
if( t2 == Type::TOP ) return Type::TOP;
// We always generate the dynamic check for 0.
// 0 MOD X is 0
if( t1 == TypeLong::ZERO ) return TypeLong::ZERO;
// X MOD X is 0
if( phase->eqv( in(1), in(2) ) ) return TypeLong::ZERO;
// Either input is BOTTOM ==> the result is the local BOTTOM
const Type *bot = bottom_type();
if( (t1 == bot) || (t2 == bot) ||
(t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
return bot;
const TypeLong *i1 = t1->is_long();
const TypeLong *i2 = t2->is_long();
if( !i1->is_con() || !i2->is_con() ) {
if( i1->_lo >= CONST64(0) && i2->_lo >= CONST64(0) )
return TypeLong::POS;
// If both numbers are not constants, we know little.
return TypeLong::LONG;
}
// Mod by zero? Throw exception at runtime!
if( !i2->get_con() ) return TypeLong::POS;
// We must be modulo'ing 2 float constants.
// Check for min_jint % '-1', result is defined to be '0'.
if( i1->get_con() == min_jlong && i2->get_con() == -1 )
return TypeLong::ZERO;
return TypeLong::make( i1->get_con() % i2->get_con() );
}
//=============================================================================
//------------------------------Value------------------------------------------
const Type* ModFNode::Value(PhaseGVN* phase) const {
// Either input is TOP ==> the result is TOP
const Type *t1 = phase->type( in(1) );
const Type *t2 = phase->type( in(2) );
if( t1 == Type::TOP ) return Type::TOP;
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