//=============================================================================
//------------------------------Ideal------------------------------------------
// Check for power-of-2 multiply, then try the regular MulNode::Ideal
Node *MulLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
// Swap constant to right
if( in(1)->is_Con() ) {
Node *t = in(1);
set_req(1,in(2));
set_req(2,t);
} else if( !in(2)->is_Con() )
return MulNode::Ideal(phase, can_reshape);
// Now we have a constant Node on the right and the constant in con
const TypeLong *tl2 = phase->type( in(2) )->isa_long();
if( !tl2 ) return NULL; // Might be top
jlong con = tl2->isa_long()->get_con();
if( con == CONST64(0) ) return NULL; // By zero is handled by Value call
if( con == CONST64(1) ) return NULL; // By one is handled by Identity call
// Check for negative constant; if so negate the final result
bool sign_flip = false;
if( con < 0 ) {
con = -con;
sign_flip = true;
}
// Get low bit; check for being the only bit
Node *res = NULL;
jlong bit1 = con & -con; // Extract low bit
if( bit1 == con ) { // Found a power of 2?
res = new (3) LShiftLNode( in(1), phase->intcon(log2_long(bit1)) );
} else {
// Check for constant with 2 bits set
jlong bit2 = con-bit1;
bit2 = bit2 & -bit2; // Extract 2nd bit
if( bit2 + bit1 == con ) { // Found all bits in con?
Node *n1 = phase->transform( new (3) LShiftLNode( in(1), phase->intcon(log2_long(bit1)) ) );
Node *n2 = phase->transform( new (3) LShiftLNode( in(1), phase->intcon(log2_long(bit2)) ) );
res = new (3) AddLNode( n2, n1 );
} else {
// Sleezy: power-of-2 -1. Next time be generic.
jlong temp = con + 1;
if( temp == (temp & -temp) ) {
Node *n1 = phase->transform( new (3) LShiftLNode( in(1), phase->intcon(log2_long(temp)) ) );
res = new (3) SubLNode( n1, in(1) );
} else {
return MulNode::Ideal(phase, can_reshape);
}
}
}
if( sign_flip ) { // Need to negate result?
res = phase->transform(res);// Transform, before making the zero con
res = new (3) SubLNode(phase->makecon(TypeLong::ZERO),res);
}
return res; // Return final result
}
void HeapRegion::setup_heap_region_size(uintx min_heap_size) {
// region_size in bytes
uintx region_size = G1HeapRegionSize;
if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
// We base the automatic calculation on the min heap size. This
// can be problematic if the spread between min and max is quite
// wide, imagine -Xms128m -Xmx32g. But, if we decided it based on
// the max size, the region size might be way too large for the
// min size. Either way, some users might have to set the region
// size manually for some -Xms / -Xmx combos.
region_size = MAX2(min_heap_size / TARGET_REGION_NUMBER,
(uintx) MIN_REGION_SIZE);
}
int region_size_log = log2_long((jlong) region_size);
// Recalculate the region size to make sure it's a power of
// 2. This means that region_size is the largest power of 2 that's
// <= what we've calculated so far.
region_size = ((uintx)1 << region_size_log);
// Now make sure that we don't go over or under our limits.
if (region_size < MIN_REGION_SIZE) {
region_size = MIN_REGION_SIZE;
} else if (region_size > MAX_REGION_SIZE) {
region_size = MAX_REGION_SIZE;
}
// And recalculate the log.
region_size_log = log2_long((jlong) region_size);
// Now, set up the globals.
guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
LogOfHRGrainBytes = region_size_log;
guarantee(LogOfHRGrainWords == 0, "we should only set it once");
LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
guarantee(GrainBytes == 0, "we should only set it once");
// The cast to int is safe, given that we've bounded region_size by
// MIN_REGION_SIZE and MAX_REGION_SIZE.
GrainBytes = (int) region_size;
guarantee(GrainWords == 0, "we should only set it once");
GrainWords = GrainBytes >> LogHeapWordSize;
guarantee(1 << LogOfHRGrainWords == GrainWords, "sanity");
guarantee(CardsPerRegion == 0, "we should only set it once");
CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
}
void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
uintx region_size = G1HeapRegionSize;
if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
region_size = MAX2(average_heap_size / TARGET_REGION_NUMBER,
(uintx) MIN_REGION_SIZE);
}
int region_size_log = log2_long((jlong) region_size);
// Recalculate the region size to make sure it's a power of
// 2. This means that region_size is the largest power of 2 that's
// <= what we've calculated so far.
region_size = ((uintx)1 << region_size_log);
// Now make sure that we don't go over or under our limits.
if (region_size < MIN_REGION_SIZE) {
region_size = MIN_REGION_SIZE;
} else if (region_size > MAX_REGION_SIZE) {
region_size = MAX_REGION_SIZE;
}
// And recalculate the log.
region_size_log = log2_long((jlong) region_size);
// Now, set up the globals.
guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
LogOfHRGrainBytes = region_size_log;
guarantee(LogOfHRGrainWords == 0, "we should only set it once");
LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
guarantee(GrainBytes == 0, "we should only set it once");
// The cast to int is safe, given that we've bounded region_size by
// MIN_REGION_SIZE and MAX_REGION_SIZE.
GrainBytes = (size_t)region_size;
guarantee(GrainWords == 0, "we should only set it once");
GrainWords = GrainBytes >> LogHeapWordSize;
guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
guarantee(CardsPerRegion == 0, "we should only set it once");
CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
}
//* the argument must be exactly a power of 2
inline int exact_log2_long(jlong x) {
#ifdef ASSERT
if (!is_power_of_2_long(x)) basic_fatal("x must be a power of 2");
#endif
return log2_long(x);
}
inline void MacroAssembler::round_to(Register r, int modulus) {
assert(is_power_of_2_long((jlong)modulus), "must be power of 2");
addi(r, r, modulus-1);
clrrdi(r, r, log2_long((jlong)modulus));
}
