From 63dd5353570e111ce9ed0c1a0512b2d91377c601 Mon Sep 17 00:00:00 2001 From: naruse Date: Mon, 27 Jun 2016 18:30:12 +0000 Subject: * insns.def (opt_plus): use `- 1` instead of `& (~1)` to allow compilers to use x86 LEA instruction (3 operand). Even if 3 operand LEA's latency is 3 cycle after SandyBridge, it reduces code size and can be faster because of super scalar. * insns.def (opt_plus): calculate and use rb_int2big. On positive Fixnum overflow, `recv - 1 + obj` doesn't carry because recv's msb and obj's msb are 0, and resulted msb is 1. Therefore simply rshift and cast as signed long works fine. On negative Fixnum overflow, it will carry because both arguments' msb are 1, and resulted msb is also 1. In this case it needs to restore carried sign bit after rshift. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55515 b2dd03c8-39d4-4d8f-98ff-823fe69b080e --- ChangeLog | 15 +++++++++++++++ insns.def | 17 ++++++----------- 2 files changed, 21 insertions(+), 11 deletions(-) diff --git a/ChangeLog b/ChangeLog index cd43b4a272..6be1c45802 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,18 @@ +Tue Jun 28 02:41:32 2016 NARUSE, Yui + + * insns.def (opt_plus): use `- 1` instead of `& (~1)` to allow + compilers to use x86 LEA instruction (3 operand). + Even if 3 operand LEA's latency is 3 cycle after SandyBridge, + it reduces code size and can be faster because of super scalar. + + * insns.def (opt_plus): calculate and use rb_int2big. + On positive Fixnum overflow, `recv - 1 + obj` doesn't carry + because recv's msb and obj's msb are 0, and resulted msb is 1. + Therefore simply rshift and cast as signed long works fine. + On negative Fixnum overflow, it will carry because both arguments' + msb are 1, and resulted msb is also 1. + In this case it needs to restore carried sign bit after rshift. + Mon Jun 27 16:58:32 2016 Nobuyoshi Nakada * lib/fileutils.rb (FileUtils#install): accecpt symbolic mode, as diff --git a/insns.def b/insns.def index cdc82872ab..6a3a39cae8 100644 --- a/insns.def +++ b/insns.def @@ -1381,18 +1381,13 @@ opt_plus BASIC_OP_UNREDEFINED_P(BOP_PLUS,INTEGER_REDEFINED_OP_FLAG)) { /* fixnum + fixnum */ #ifndef LONG_LONG_VALUE - val = (recv + (obj & (~1))); - if ((~(recv ^ obj) & (recv ^ val)) & - ((VALUE)0x01 << ((sizeof(VALUE) * CHAR_BIT) - 1))) { - val = rb_big_plus(rb_int2big(FIX2LONG(recv)), - rb_int2big(FIX2LONG(obj))); - } + VALUE msb = (VALUE)1 << ((sizeof(VALUE) * CHAR_BIT) - 1); + val = recv - 1 + obj; + if ((~(recv ^ obj) & (recv ^ val)) & msb) { + val = rb_int2big((SIGNED_VALUE)((val>>1) | (recv & msb))); + } #else - long a, b, c; - a = FIX2LONG(recv); - b = FIX2LONG(obj); - c = a + b; - val = LONG2NUM(c); + val = LONG2NUM(FIX2LONG(recv) + FIX2LONG(obj)); #endif } else if (FLONUM_2_P(recv, obj) && -- cgit v1.2.3