On Tue, 5 Apr 2022 20:26:18 GMT, Vamsi Parasa <d...@openjdk.java.net> wrote:
>> Optimizes the divideUnsigned() and remainderUnsigned() methods in
>> java.lang.Integer and java.lang.Long classes using x86 intrinsics. This
>> change shows 3x improvement for Integer methods and upto 25% improvement for
>> Long. This change also implements the DivMod optimization which fuses
>> division and modulus operations if needed. The DivMod optimization shows 3x
>> improvement for Integer and ~65% improvement for Long.
>
> Vamsi Parasa has updated the pull request incrementally with one additional
> commit since the last revision:
>
> add error msg for jtreg test
I have few comments.
src/hotspot/cpu/x86/assembler_x86.cpp line 12375:
> 12373: }
> 12374: #endif
> 12375:
Please, place it near `idivq()` so you would not need `#ifdef`.
src/hotspot/cpu/x86/c2_MacroAssembler_x86.cpp line 4568:
> 4566: subl(rdx, divisor);
> 4567: if (VM_Version::supports_bmi1()) andnl(rax, rdx, rax);
> 4568: else {
Please, follow our coding stile here and in following methods:
if (VM_Version::supports_bmi1()) {
andnl(rax, rdx, rax);
} else {
src/hotspot/cpu/x86/x86_64.ad line 8701:
> 8699: %}
> 8700:
> 8701: instruct udivI_rReg(rax_RegI rax, no_rax_rdx_RegI div, rFlagsReg cr,
> rdx_RegI rdx)
I suggest to follow the pattern in other `div/mod` instructions: `(rax_RegI
rax, rdx_RegI rdx, no_rax_rdx_RegI div, rFlagsReg cr)`
Similar in following new instructions.
test/hotspot/jtreg/compiler/intrinsics/TestIntegerDivMod.java line 55:
> 53: dividends[i] = rng.nextInt();
> 54: divisors[i] = rng.nextInt();
> 55: }
I don't trust RND to generate corner cases.
Please, add cases here and in TestLongDivMod.java for MAX, MIN, 0.
-------------
Changes requested by kvn (Reviewer).
PR: https://git.openjdk.java.net/jdk/pull/7572
