On Wed, 14 Aug 2024 04:59:23 GMT, Jatin Bhateja <jbhat...@openjdk.org> wrote:
>> Hi All, >> >> As per the discussion on panama-dev mailing list[1], patch adds the support >> following new vector operators. >> >> >> . SUADD : Saturating unsigned addition. >> . SADD : Saturating signed addition. >> . SUSUB : Saturating unsigned subtraction. >> . SSUB : Saturating signed subtraction. >> . UMAX : Unsigned max >> . UMIN : Unsigned min. >> >> >> New vector operators are applicable to only integral types since their >> values wraparound in over/underflowing scenarios after setting appropriate >> status flags. For floating point types, as per IEEE 754 specs there are >> multiple schemes to handler underflow, one of them is gradual underflow >> which transitions the value to subnormal range. Similarly, overflow >> implicitly saturates the floating-point value to an Infinite value. >> >> As the name suggests, these are saturating operations, i.e. the result of >> the computation is strictly capped by lower and upper bounds of the result >> type and is not wrapped around in underflowing or overflowing scenarios. >> >> Summary of changes: >> - Java side implementation of new vector operators. >> - Add new scalar saturating APIs for each of the above saturating vector >> operator in corresponding primitive box classes, fallback implementation of >> vector operators is based over it. >> - C2 compiler IR and inline expander changes. >> - Optimized x86 backend implementation for new vector operators and their >> predicated counterparts. >> - Extends existing VectorAPI Jtreg test suite to cover new operations. >> >> Kindly review and share your feedback. >> >> Best Regards, >> PS: Intrinsification and auto-vectorization of new core-lib API will be >> addressed separately in a follow-up patch. >> >> [1] https://mail.openjdk.org/pipermail/panama-dev/2024-May/020408.html > > Jatin Bhateja has updated the pull request incrementally with one additional > commit since the last revision: > > Review comments resolutions src/java.base/share/classes/java/lang/Byte.java line 81: > 79: * A constant holding polarity(sign) mask used by saturating > operations. > 80: */ > 81: public static final byte POLARITY_MASK_BYTE = (byte)(1 << 7); Suggestion: public static final byte POLARITY_MASK_BYTE = (byte)(1 << 7); src/java.base/share/classes/java/lang/Byte.java line 672: > 670: byte res = (byte)(a + b); > 671: boolean overflow = Byte.compareUnsigned(res, (byte)(a | b)) < 0; > 672: if (overflow) { Suggestion: if (overflow) { src/java.base/share/classes/java/lang/Long.java line 93: > 91: * A constant holding polarity(sign) mask used by saturating > operations. > 92: */ > 93: public static final long POLARITY_MASK_LONG = 1L << 63; Suggestion: public static final long POLARITY_MASK_LONG = 1L << 63; src/java.base/share/classes/java/lang/Long.java line 2033: > 2031: long res = a + b; > 2032: boolean overflow = Long.compareUnsigned(res, (a | b)) < 0; > 2033: if (overflow) { Suggestion: if (overflow) { src/java.base/share/classes/java/lang/Short.java line 707: > 705: short res = (short)(a + b); > 706: boolean overflow = Short.compareUnsigned(res, (short)(a | b)) < > 0; > 707: if (overflow) { Suggestion: if (overflow) { ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/20507#discussion_r1720807587 PR Review Comment: https://git.openjdk.org/jdk/pull/20507#discussion_r1720807612 PR Review Comment: https://git.openjdk.org/jdk/pull/20507#discussion_r1720807574 PR Review Comment: https://git.openjdk.org/jdk/pull/20507#discussion_r1720807513 PR Review Comment: https://git.openjdk.org/jdk/pull/20507#discussion_r1720807466
