8358179: Performance regression in Math.cbrt

Reviewed-by: sviswanathan, sparasa, epeter
This commit is contained in:
Mohamed Issa 2025-07-01 15:34:37 +00:00 committed by Sandhya Viswanathan
parent e1681c4828
commit 38f59f84c9

View File

@ -46,6 +46,12 @@
//
/******************************************************************************/
/* Represents 0x7FFFFFFFFFFFFFFF double precision in lower 64 bits*/
ATTRIBUTE_ALIGNED(16) static const juint _ABS_MASK[] =
{
4294967295, 2147483647, 0, 0
};
ATTRIBUTE_ALIGNED(4) static const juint _SIG_MASK[] =
{
0, 1032192
@ -188,10 +194,10 @@ address StubGenerator::generate_libmCbrt() {
StubCodeMark mark(this, stub_id);
address start = __ pc();
Label L_2TAG_PACKET_0_0_1, L_2TAG_PACKET_1_0_1, L_2TAG_PACKET_2_0_1, L_2TAG_PACKET_3_0_1;
Label L_2TAG_PACKET_4_0_1, L_2TAG_PACKET_5_0_1, L_2TAG_PACKET_6_0_1;
Label L_2TAG_PACKET_0_0_1, L_2TAG_PACKET_1_0_1, L_2TAG_PACKET_2_0_1;
Label B1_1, B1_2, B1_4;
address ABS_MASK = (address)_ABS_MASK;
address SIG_MASK = (address)_SIG_MASK;
address EXP_MASK = (address)_EXP_MASK;
address EXP_MSK2 = (address)_EXP_MSK2;
@ -208,8 +214,12 @@ address StubGenerator::generate_libmCbrt() {
__ enter(); // required for proper stackwalking of RuntimeStub frame
__ bind(B1_1);
__ subq(rsp, 24);
__ movsd(Address(rsp), xmm0);
__ ucomisd(xmm0, ExternalAddress(ZERON), r11 /*rscratch*/);
__ jcc(Assembler::equal, L_2TAG_PACKET_1_0_1); // Branch only if x is +/- zero or NaN
__ movq(xmm1, xmm0);
__ andpd(xmm1, ExternalAddress(ABS_MASK), r11 /*rscratch*/);
__ ucomisd(xmm1, ExternalAddress(INF), r11 /*rscratch*/);
__ jcc(Assembler::equal, B1_4); // Branch only if x is +/- INF
__ bind(B1_2);
__ movq(xmm7, xmm0);
@ -228,8 +238,6 @@ address StubGenerator::generate_libmCbrt() {
__ andl(rdx, rax);
__ cmpl(rdx, 0);
__ jcc(Assembler::equal, L_2TAG_PACKET_0_0_1); // Branch only if |x| is denormalized
__ cmpl(rdx, 524032);
__ jcc(Assembler::equal, L_2TAG_PACKET_1_0_1); // Branch only if |x| is INF or NaN
__ shrl(rdx, 8);
__ shrq(r9, 8);
__ andpd(xmm2, xmm0);
@ -297,8 +305,6 @@ address StubGenerator::generate_libmCbrt() {
__ andl(rdx, rax);
__ shrl(rdx, 8);
__ shrq(r9, 8);
__ cmpl(rdx, 0);
__ jcc(Assembler::equal, L_2TAG_PACKET_3_0_1); // Branch only if |x| is zero
__ andpd(xmm2, xmm0);
__ andpd(xmm0, xmm5);
__ orpd(xmm3, xmm2);
@ -322,41 +328,10 @@ address StubGenerator::generate_libmCbrt() {
__ psllq(xmm7, 52);
__ jmp(L_2TAG_PACKET_2_0_1);
__ bind(L_2TAG_PACKET_3_0_1);
__ cmpq(r9, 0);
__ jcc(Assembler::notEqual, L_2TAG_PACKET_4_0_1); // Branch only if x is negative zero
__ xorpd(xmm0, xmm0);
__ jmp(B1_4);
__ bind(L_2TAG_PACKET_4_0_1);
__ movsd(xmm0, ExternalAddress(ZERON), r11 /*rscratch*/);
__ jmp(B1_4);
__ bind(L_2TAG_PACKET_1_0_1);
__ movl(rax, Address(rsp, 4));
__ movl(rdx, Address(rsp));
__ movl(rcx, rax);
__ andl(rcx, 2147483647);
__ cmpl(rcx, 2146435072);
__ jcc(Assembler::above, L_2TAG_PACKET_5_0_1); // Branch only if |x| is NaN
__ cmpl(rdx, 0);
__ jcc(Assembler::notEqual, L_2TAG_PACKET_5_0_1); // Branch only if |x| is NaN
__ cmpl(rax, 2146435072);
__ jcc(Assembler::notEqual, L_2TAG_PACKET_6_0_1); // Branch only if x is negative INF
__ movsd(xmm0, ExternalAddress(INF), r11 /*rscratch*/);
__ jmp(B1_4);
__ bind(L_2TAG_PACKET_6_0_1);
__ movsd(xmm0, ExternalAddress(NEG_INF), r11 /*rscratch*/);
__ jmp(B1_4);
__ bind(L_2TAG_PACKET_5_0_1);
__ movsd(xmm0, Address(rsp));
__ addsd(xmm0, xmm0);
__ movq(Address(rsp, 8), xmm0);
__ bind(B1_4);
__ addq(rsp, 24);
__ leave(); // required for proper stackwalking of RuntimeStub frame
__ ret(0);