8205194: Improve the Array Comparison when there is mismatch at first element.
Summary: perform the first element comparison before the call to vectorizedMismatch method
Reviewed-by: psandoz, rriggs, igerasim
--- a/src/java.base/share/classes/java/nio/BufferMismatch.java Fri Jun 22 12:05:36 2018 -0700
+++ b/src/java.base/share/classes/java/nio/BufferMismatch.java Fri Jun 22 12:51:49 2018 -0700
@@ -34,6 +34,8 @@
static int mismatch(ByteBuffer a, int aOff, ByteBuffer b, int bOff, int length) {
int i = 0;
if (length > 7) {
+ if (a.get(aOff) != b.get(bOff))
+ return 0;
i = ArraysSupport.vectorizedMismatch(
a.base(), a.address + aOff,
b.base(), b.address + bOff,
@@ -56,6 +58,8 @@
// (order is null) then the slow path is taken
if (length > 3 && a.charRegionOrder() == b.charRegionOrder()
&& a.charRegionOrder() != null && b.charRegionOrder() != null) {
+ if (a.get(aOff) != b.get(bOff))
+ return 0;
i = ArraysSupport.vectorizedMismatch(
a.base(), a.address + (aOff << ArraysSupport.LOG2_ARRAY_CHAR_INDEX_SCALE),
b.base(), b.address + (bOff << ArraysSupport.LOG2_ARRAY_CHAR_INDEX_SCALE),
@@ -74,6 +78,8 @@
static int mismatch(ShortBuffer a, int aOff, ShortBuffer b, int bOff, int length) {
int i = 0;
if (length > 3 && a.order() == b.order()) {
+ if (a.get(aOff) != b.get(bOff))
+ return 0;
i = ArraysSupport.vectorizedMismatch(
a.base(), a.address + (aOff << ArraysSupport.LOG2_ARRAY_SHORT_INDEX_SCALE),
b.base(), b.address + (bOff << ArraysSupport.LOG2_ARRAY_SHORT_INDEX_SCALE),
@@ -92,6 +98,8 @@
static int mismatch(IntBuffer a, int aOff, IntBuffer b, int bOff, int length) {
int i = 0;
if (length > 1 && a.order() == b.order()) {
+ if (a.get(aOff) != b.get(bOff))
+ return 0;
i = ArraysSupport.vectorizedMismatch(
a.base(), a.address + (aOff << ArraysSupport.LOG2_ARRAY_INT_INDEX_SCALE),
b.base(), b.address + (bOff << ArraysSupport.LOG2_ARRAY_INT_INDEX_SCALE),
@@ -110,11 +118,13 @@
static int mismatch(FloatBuffer a, int aOff, FloatBuffer b, int bOff, int length) {
int i = 0;
if (length > 1 && a.order() == b.order()) {
- i = ArraysSupport.vectorizedMismatch(
- a.base(), a.address + (aOff << ArraysSupport.LOG2_ARRAY_FLOAT_INDEX_SCALE),
- b.base(), b.address + (bOff << ArraysSupport.LOG2_ARRAY_FLOAT_INDEX_SCALE),
- length,
- ArraysSupport.LOG2_ARRAY_FLOAT_INDEX_SCALE);
+ if (Float.floatToRawIntBits(a.get(aOff)) == Float.floatToRawIntBits(b.get(bOff))) {
+ i = ArraysSupport.vectorizedMismatch(
+ a.base(), a.address + (aOff << ArraysSupport.LOG2_ARRAY_FLOAT_INDEX_SCALE),
+ b.base(), b.address + (bOff << ArraysSupport.LOG2_ARRAY_FLOAT_INDEX_SCALE),
+ length,
+ ArraysSupport.LOG2_ARRAY_FLOAT_INDEX_SCALE);
+ }
// Mismatched
if (i >= 0) {
// Check if mismatch is not associated with two NaN values; and
@@ -146,6 +156,8 @@
static int mismatch(LongBuffer a, int aOff, LongBuffer b, int bOff, int length) {
int i = 0;
if (length > 0 && a.order() == b.order()) {
+ if (a.get(aOff) != b.get(bOff))
+ return 0;
i = ArraysSupport.vectorizedMismatch(
a.base(), a.address + (aOff << ArraysSupport.LOG2_ARRAY_LONG_INDEX_SCALE),
b.base(), b.address + (bOff << ArraysSupport.LOG2_ARRAY_LONG_INDEX_SCALE),
@@ -163,11 +175,13 @@
static int mismatch(DoubleBuffer a, int aOff, DoubleBuffer b, int bOff, int length) {
int i = 0;
if (length > 0 && a.order() == b.order()) {
- i = ArraysSupport.vectorizedMismatch(
- a.base(), a.address + (aOff << ArraysSupport.LOG2_ARRAY_DOUBLE_INDEX_SCALE),
- b.base(), b.address + (bOff << ArraysSupport.LOG2_ARRAY_DOUBLE_INDEX_SCALE),
- length,
- ArraysSupport.LOG2_ARRAY_DOUBLE_INDEX_SCALE);
+ if (Double.doubleToRawLongBits(a.get(aOff)) == Double.doubleToRawLongBits(b.get(bOff))) {
+ i = ArraysSupport.vectorizedMismatch(
+ a.base(), a.address + (aOff << ArraysSupport.LOG2_ARRAY_DOUBLE_INDEX_SCALE),
+ b.base(), b.address + (bOff << ArraysSupport.LOG2_ARRAY_DOUBLE_INDEX_SCALE),
+ length,
+ ArraysSupport.LOG2_ARRAY_DOUBLE_INDEX_SCALE);
+ }
// Mismatched
if (i >= 0) {
// Check if mismatch is not associated with two NaN values; and
--- a/src/java.base/share/classes/jdk/internal/util/ArraysSupport.java Fri Jun 22 12:05:36 2018 -0700
+++ b/src/java.base/share/classes/jdk/internal/util/ArraysSupport.java Fri Jun 22 12:51:49 2018 -0700
@@ -166,6 +166,8 @@
int length) {
int i = 0;
if (length > 7) {
+ if (a[0] != b[0])
+ return 0;
i = vectorizedMismatch(
a, Unsafe.ARRAY_BOOLEAN_BASE_OFFSET,
b, Unsafe.ARRAY_BOOLEAN_BASE_OFFSET,
@@ -186,6 +188,8 @@
int length) {
int i = 0;
if (length > 7) {
+ if (a[aFromIndex] != b[bFromIndex])
+ return 0;
int aOffset = Unsafe.ARRAY_BOOLEAN_BASE_OFFSET + aFromIndex;
int bOffset = Unsafe.ARRAY_BOOLEAN_BASE_OFFSET + bFromIndex;
i = vectorizedMismatch(
@@ -228,6 +232,8 @@
int i = 0;
if (length > 7) {
+ if (a[0] != b[0])
+ return 0;
i = vectorizedMismatch(
a, Unsafe.ARRAY_BYTE_BASE_OFFSET,
b, Unsafe.ARRAY_BYTE_BASE_OFFSET,
@@ -275,6 +281,8 @@
int i = 0;
if (length > 7) {
+ if (a[aFromIndex] != b[bFromIndex])
+ return 0;
int aOffset = Unsafe.ARRAY_BYTE_BASE_OFFSET + aFromIndex;
int bOffset = Unsafe.ARRAY_BYTE_BASE_OFFSET + bFromIndex;
i = vectorizedMismatch(
@@ -300,6 +308,8 @@
int length) {
int i = 0;
if (length > 3) {
+ if (a[0] != b[0])
+ return 0;
i = vectorizedMismatch(
a, Unsafe.ARRAY_CHAR_BASE_OFFSET,
b, Unsafe.ARRAY_CHAR_BASE_OFFSET,
@@ -320,6 +330,8 @@
int length) {
int i = 0;
if (length > 3) {
+ if (a[aFromIndex] != b[bFromIndex])
+ return 0;
int aOffset = Unsafe.ARRAY_CHAR_BASE_OFFSET + (aFromIndex << LOG2_ARRAY_CHAR_INDEX_SCALE);
int bOffset = Unsafe.ARRAY_CHAR_BASE_OFFSET + (bFromIndex << LOG2_ARRAY_CHAR_INDEX_SCALE);
i = vectorizedMismatch(
@@ -345,6 +357,8 @@
int length) {
int i = 0;
if (length > 3) {
+ if (a[0] != b[0])
+ return 0;
i = vectorizedMismatch(
a, Unsafe.ARRAY_SHORT_BASE_OFFSET,
b, Unsafe.ARRAY_SHORT_BASE_OFFSET,
@@ -365,6 +379,8 @@
int length) {
int i = 0;
if (length > 3) {
+ if (a[aFromIndex] != b[bFromIndex])
+ return 0;
int aOffset = Unsafe.ARRAY_SHORT_BASE_OFFSET + (aFromIndex << LOG2_ARRAY_SHORT_INDEX_SCALE);
int bOffset = Unsafe.ARRAY_SHORT_BASE_OFFSET + (bFromIndex << LOG2_ARRAY_SHORT_INDEX_SCALE);
i = vectorizedMismatch(
@@ -390,6 +406,8 @@
int length) {
int i = 0;
if (length > 1) {
+ if (a[0] != b[0])
+ return 0;
i = vectorizedMismatch(
a, Unsafe.ARRAY_INT_BASE_OFFSET,
b, Unsafe.ARRAY_INT_BASE_OFFSET,
@@ -410,6 +428,8 @@
int length) {
int i = 0;
if (length > 1) {
+ if (a[aFromIndex] != b[bFromIndex])
+ return 0;
int aOffset = Unsafe.ARRAY_INT_BASE_OFFSET + (aFromIndex << LOG2_ARRAY_INT_INDEX_SCALE);
int bOffset = Unsafe.ARRAY_INT_BASE_OFFSET + (bFromIndex << LOG2_ARRAY_INT_INDEX_SCALE);
i = vectorizedMismatch(
@@ -441,12 +461,14 @@
int length) {
int i = 0;
if (length > 1) {
- int aOffset = Unsafe.ARRAY_FLOAT_BASE_OFFSET + (aFromIndex << LOG2_ARRAY_FLOAT_INDEX_SCALE);
- int bOffset = Unsafe.ARRAY_FLOAT_BASE_OFFSET + (bFromIndex << LOG2_ARRAY_FLOAT_INDEX_SCALE);
- i = vectorizedMismatch(
- a, aOffset,
- b, bOffset,
- length, LOG2_ARRAY_FLOAT_INDEX_SCALE);
+ if (Float.floatToRawIntBits(a[aFromIndex]) == Float.floatToRawIntBits(b[bFromIndex])) {
+ int aOffset = Unsafe.ARRAY_FLOAT_BASE_OFFSET + (aFromIndex << LOG2_ARRAY_FLOAT_INDEX_SCALE);
+ int bOffset = Unsafe.ARRAY_FLOAT_BASE_OFFSET + (bFromIndex << LOG2_ARRAY_FLOAT_INDEX_SCALE);
+ i = vectorizedMismatch(
+ a, aOffset,
+ b, bOffset,
+ length, LOG2_ARRAY_FLOAT_INDEX_SCALE);
+ }
// Mismatched
if (i >= 0) {
// Check if mismatch is not associated with two NaN values
@@ -481,6 +503,8 @@
if (length == 0) {
return -1;
}
+ if (a[0] != b[0])
+ return 0;
int i = vectorizedMismatch(
a, Unsafe.ARRAY_LONG_BASE_OFFSET,
b, Unsafe.ARRAY_LONG_BASE_OFFSET,
@@ -494,6 +518,8 @@
if (length == 0) {
return -1;
}
+ if (a[aFromIndex] != b[bFromIndex])
+ return 0;
int aOffset = Unsafe.ARRAY_LONG_BASE_OFFSET + (aFromIndex << LOG2_ARRAY_LONG_INDEX_SCALE);
int bOffset = Unsafe.ARRAY_LONG_BASE_OFFSET + (bFromIndex << LOG2_ARRAY_LONG_INDEX_SCALE);
int i = vectorizedMismatch(
@@ -518,12 +544,15 @@
if (length == 0) {
return -1;
}
- int aOffset = Unsafe.ARRAY_DOUBLE_BASE_OFFSET + (aFromIndex << LOG2_ARRAY_DOUBLE_INDEX_SCALE);
- int bOffset = Unsafe.ARRAY_DOUBLE_BASE_OFFSET + (bFromIndex << LOG2_ARRAY_DOUBLE_INDEX_SCALE);
- int i = vectorizedMismatch(
- a, aOffset,
- b, bOffset,
- length, LOG2_ARRAY_DOUBLE_INDEX_SCALE);
+ int i = 0;
+ if (Double.doubleToRawLongBits(a[aFromIndex]) == Double.doubleToRawLongBits(b[bFromIndex])) {
+ int aOffset = Unsafe.ARRAY_DOUBLE_BASE_OFFSET + (aFromIndex << LOG2_ARRAY_DOUBLE_INDEX_SCALE);
+ int bOffset = Unsafe.ARRAY_DOUBLE_BASE_OFFSET + (bFromIndex << LOG2_ARRAY_DOUBLE_INDEX_SCALE);
+ i = vectorizedMismatch(
+ a, aOffset,
+ b, bOffset,
+ length, LOG2_ARRAY_DOUBLE_INDEX_SCALE);
+ }
if (i >= 0) {
// Check if mismatch is not associated with two NaN values
if (!Double.isNaN(a[aFromIndex + i]) || !Double.isNaN(b[bFromIndex + i]))