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6987135: Performance regression on Intel platform with 32-bits edition between 6u13 and 6u14

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Use hardware DIV instruction for long division by constant when it is faster than code with multiply.

Reviewed-by: never
This commit is contained in:
Vladimir Kozlov 2010-11-02 09:00:37 -07:00
parent ce0125e7f2
commit 249b1f6c4f
10 changed files with 180 additions and 23 deletions
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12
hotspot/src/cpu/sparc/vm/vm_version_sparc.hpp
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@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2009, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -33,7 +33,9 @@ protected:
v9_instructions = 5,
vis1_instructions = 6,
vis2_instructions = 7,
sun4v_instructions = 8
sun4v_instructions = 8,
blk_init_instructions = 9,
fmaf_instructions = 10
};
enum Feature_Flag_Set {
@ -49,6 +51,8 @@ protected:
vis1_instructions_m = 1 << vis1_instructions,
vis2_instructions_m = 1 << vis2_instructions,
sun4v_m = 1 << sun4v_instructions,
blk_init_instructions_m = 1 << blk_init_instructions,
fmaf_instructions_m = 1 << fmaf_instructions,
generic_v8_m = v8_instructions_m | hardware_mul32_m | hardware_div32_m | hardware_fsmuld_m,
generic_v9_m = generic_v8_m | v9_instructions_m,
@ -67,6 +71,7 @@ protected:
static int platform_features(int features);
static bool is_niagara1(int features) { return (features & sun4v_m) != 0; }
static bool is_sparc64(int features) { return (features & fmaf_instructions_m) != 0; }
static int maximum_niagara1_processor_count() { return 32; }
// Returns true if the platform is in the niagara line and
@ -86,6 +91,7 @@ public:
static bool has_hardware_popc() { return (_features & hardware_popc_m) != 0; }
static bool has_vis1() { return (_features & vis1_instructions_m) != 0; }
static bool has_vis2() { return (_features & vis2_instructions_m) != 0; }
static bool has_blk_init() { return (_features & blk_init_instructions_m) != 0; }
static bool supports_compare_and_exchange()
{ return has_v9(); }
@ -93,8 +99,10 @@ public:
static bool is_ultra3() { return (_features & ultra3_m) == ultra3_m; }
static bool is_sun4v() { return (_features & sun4v_m) != 0; }
static bool is_niagara1() { return is_niagara1(_features); }
static bool is_sparc64() { return is_sparc64(_features); }
static bool has_fast_fxtof() { return has_v9() && !is_ultra3(); }
static bool has_fast_idiv() { return is_niagara1_plus() || is_sparc64(); }
static const char* cpu_features() { return _features_str; }