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src/hotspot/share/opto/regmask.cpp

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rev 60615 : 8231441: Initial SVE backend support
Reviewed-by: adinn, pli
Contributed-by: joshua.zhu@arm.com, yang.zhang@arm.com, ningsheng.jian@arm.com
   1 /*
   2  * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "opto/ad.hpp"

  27 #include "opto/compile.hpp"
  28 #include "opto/matcher.hpp"
  29 #include "opto/node.hpp"
  30 #include "opto/regmask.hpp"
  31 #include "utilities/population_count.hpp"
  32 #include "utilities/powerOfTwo.hpp"
  33 
  34 #define RM_SIZE _RM_SIZE /* a constant private to the class RegMask */
  35 
  36 //------------------------------dump-------------------------------------------
  37 
  38 #ifndef PRODUCT
  39 void OptoReg::dump(int r, outputStream *st) {
  40   switch (r) {
  41   case Special: st->print("r---"); break;
  42   case Bad:     st->print("rBAD"); break;
  43   default:
  44     if (r < _last_Mach_Reg) st->print("%s", Matcher::regName[r]);
  45     else st->print("rS%d",r);
  46     break;
  47   }
  48 }
  49 #endif
  50 
  51 
  52 //=============================================================================
  53 const RegMask RegMask::Empty(
  54 # define BODY(I) 0,
  55   FORALL_BODY
  56 # undef BODY
  57   0
  58 );
  59 
  60 //=============================================================================
  61 bool RegMask::is_vector(uint ireg) {
  62   return (ireg == Op_VecS || ireg == Op_VecD ||
  63           ireg == Op_VecX || ireg == Op_VecY || ireg == Op_VecZ );
  64 }
  65 
  66 int RegMask::num_registers(uint ireg) {
  67     switch(ireg) {
  68       case Op_VecZ:
  69         return 16;
  70       case Op_VecY:
  71         return 8;
  72       case Op_VecX:
  73         return 4;
  74       case Op_VecD:

  75       case Op_RegD:
  76       case Op_RegL:
  77 #ifdef _LP64
  78       case Op_RegP:
  79 #endif
  80         return 2;



  81     }
  82     // Op_VecS and the rest ideal registers.
  83     return 1;
  84 }
  85 













  86 // Clear out partial bits; leave only bit pairs
  87 void RegMask::clear_to_pairs() {
  88   assert(valid_watermarks(), "sanity");
  89   for (int i = _lwm; i <= _hwm; i++) {
  90     int bits = _A[i];
  91     bits &= ((bits & 0x55555555)<<1); // 1 hi-bit set for each pair
  92     bits |= (bits>>1);          // Smear 1 hi-bit into a pair
  93     _A[i] = bits;
  94   }
  95   assert(is_aligned_pairs(), "mask is not aligned, adjacent pairs");
  96 }
  97 
  98 bool RegMask::is_misaligned_pair() const {
  99   return Size() == 2 && !is_aligned_pairs();
 100 }
 101 
 102 bool RegMask::is_aligned_pairs() const {
 103   // Assert that the register mask contains only bit pairs.
 104   assert(valid_watermarks(), "sanity");
 105   for (int i = _lwm; i <= _hwm; i++) {


 140         i++;                       // Skip iteration forward
 141         if (i > _hwm || _A[i] != 1)
 142           return false; // Require 1 lo bit in next word
 143       }
 144     }
 145   }
 146   // True for both the empty mask and for a bit pair
 147   return true;
 148 }
 149 
 150 // Test for a single adjacent set of ideal register's size.
 151 bool RegMask::is_bound(uint ireg) const {
 152   if (is_vector(ireg)) {
 153     if (is_bound_set(num_registers(ireg)))
 154       return true;
 155   } else if (is_bound1() || is_bound_pair()) {
 156     return true;
 157   }
 158   return false;
 159 }










 160 
 161 // only indicies of power 2 are accessed, so index 3 is only filled in for storage.
 162 static int low_bits[5] = { 0x55555555, 0x11111111, 0x01010101, 0x00000000, 0x00010001 };
 163 
 164 // Find the lowest-numbered register set in the mask.  Return the
 165 // HIGHEST register number in the set, or BAD if no sets.
 166 // Works also for size 1.
 167 OptoReg::Name RegMask::find_first_set(const int size) const {




 168   assert(is_aligned_sets(size), "mask is not aligned, adjacent sets");

 169   assert(valid_watermarks(), "sanity");
 170   for (int i = _lwm; i <= _hwm; i++) {
 171     if (_A[i]) {                // Found some bits
 172       // Convert to bit number, return hi bit in pair
 173       return OptoReg::Name((i<<_LogWordBits) + find_lowest_bit(_A[i]) + (size - 1));
 174     }
 175   }
 176   return OptoReg::Bad;
 177 }
 178 
 179 // Clear out partial bits; leave only aligned adjacent bit pairs
 180 void RegMask::clear_to_sets(const int size) {
 181   if (size == 1) return;
 182   assert(2 <= size && size <= 16, "update low bits table");
 183   assert(is_power_of_2(size), "sanity");
 184   assert(valid_watermarks(), "sanity");
 185   int low_bits_mask = low_bits[size>>2];
 186   for (int i = _lwm; i <= _hwm; i++) {
 187     int bits = _A[i];
 188     int sets = (bits & low_bits_mask);


 228         }
 229       }
 230     }
 231     _A[i] = sets;
 232   }
 233   assert(is_aligned_sets(size), "mask is not aligned, adjacent sets");
 234 }
 235 
 236 // Assert that the register mask contains only bit sets.
 237 bool RegMask::is_aligned_sets(const int size) const {
 238   if (size == 1) return true;
 239   assert(2 <= size && size <= 16, "update low bits table");
 240   assert(is_power_of_2(size), "sanity");
 241   int low_bits_mask = low_bits[size>>2];
 242   assert(valid_watermarks(), "sanity");
 243   for (int i = _lwm; i <= _hwm; i++) {
 244     int bits = _A[i];
 245     while (bits) {              // Check bits for pairing
 246       int bit = bits & -bits;   // Extract low bit
 247       // Low bit is not odd means its mis-aligned.
 248       if ((bit & low_bits_mask) == 0) return false;


 249       // Do extra work since (bit << size) may overflow.
 250       int hi_bit = bit << (size-1); // high bit
 251       int set = hi_bit + ((hi_bit-1) & ~(bit-1));
 252       // Check for aligned adjacent bits in this set
 253       if ((bits & set) != set) return false;


 254       bits -= set;  // Remove this set
 255     }
 256   }
 257   return true;
 258 }
 259 
 260 // Return TRUE if the mask contains one adjacent set of bits and no other bits.
 261 // Works also for size 1.
 262 int RegMask::is_bound_set(const int size) const {
 263   if (is_AllStack()) return false;
 264   assert(1 <= size && size <= 16, "update low bits table");
 265   assert(valid_watermarks(), "sanity");
 266   int bit = -1;                 // Set to hold the one bit allowed
 267   for (int i = _lwm; i <= _hwm; i++) {
 268     if (_A[i] ) {               // Found some bits
 269       if (bit != -1)
 270        return false;            // Already had bits, so fail
 271       bit = _A[i] & -_A[i];     // Extract low bit from mask
 272       int hi_bit = bit << (size-1); // high bit
 273       if (hi_bit != 0) {        // Bit set stays in same word?


   1 /*
   2  * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "opto/ad.hpp"
  27 #include "opto/chaitin.hpp"
  28 #include "opto/compile.hpp"
  29 #include "opto/matcher.hpp"
  30 #include "opto/node.hpp"
  31 #include "opto/regmask.hpp"
  32 #include "utilities/population_count.hpp"
  33 #include "utilities/powerOfTwo.hpp"
  34 
  35 #define RM_SIZE _RM_SIZE /* a constant private to the class RegMask */
  36 
  37 //------------------------------dump-------------------------------------------
  38 
  39 #ifndef PRODUCT
  40 void OptoReg::dump(int r, outputStream *st) {
  41   switch (r) {
  42   case Special: st->print("r---"); break;
  43   case Bad:     st->print("rBAD"); break;
  44   default:
  45     if (r < _last_Mach_Reg) st->print("%s", Matcher::regName[r]);
  46     else st->print("rS%d",r);
  47     break;
  48   }
  49 }
  50 #endif
  51 
  52 
  53 //=============================================================================
  54 const RegMask RegMask::Empty(
  55 # define BODY(I) 0,
  56   FORALL_BODY
  57 # undef BODY
  58   0
  59 );
  60 
  61 //=============================================================================
  62 bool RegMask::is_vector(uint ireg) {
  63   return (ireg == Op_VecA || ireg == Op_VecS || ireg == Op_VecD ||
  64           ireg == Op_VecX || ireg == Op_VecY || ireg == Op_VecZ );
  65 }
  66 
  67 int RegMask::num_registers(uint ireg) {
  68     switch(ireg) {
  69       case Op_VecZ:
  70         return SlotsPerVecZ;
  71       case Op_VecY:
  72         return SlotsPerVecY;
  73       case Op_VecX:
  74         return SlotsPerVecX;
  75       case Op_VecD:
  76         return SlotsPerVecD;
  77       case Op_RegD:
  78       case Op_RegL:
  79 #ifdef _LP64
  80       case Op_RegP:
  81 #endif
  82         return 2;
  83       case Op_VecA:
  84         assert(Matcher::supports_scalable_vector(), "does not support scalable vector");
  85         return SlotsPerVecA;
  86     }
  87     // Op_VecS and the rest ideal registers.
  88     return 1;
  89 }
  90 
  91 int RegMask::num_registers(uint ireg, LRG &lrg) {
  92   int n_regs = num_registers(ireg);
  93 
  94   // assigned is OptoReg which is selected by register allocator
  95   OptoReg::Name assigned = lrg.reg();
  96   assert(OptoReg::is_valid(assigned), "should be valid opto register");
  97 
  98   if (lrg.is_scalable() && OptoReg::is_stack(assigned)) {
  99     n_regs = lrg.scalable_reg_slots();
 100   }
 101   return n_regs;
 102 }
 103 
 104 // Clear out partial bits; leave only bit pairs
 105 void RegMask::clear_to_pairs() {
 106   assert(valid_watermarks(), "sanity");
 107   for (int i = _lwm; i <= _hwm; i++) {
 108     int bits = _A[i];
 109     bits &= ((bits & 0x55555555)<<1); // 1 hi-bit set for each pair
 110     bits |= (bits>>1);          // Smear 1 hi-bit into a pair
 111     _A[i] = bits;
 112   }
 113   assert(is_aligned_pairs(), "mask is not aligned, adjacent pairs");
 114 }
 115 
 116 bool RegMask::is_misaligned_pair() const {
 117   return Size() == 2 && !is_aligned_pairs();
 118 }
 119 
 120 bool RegMask::is_aligned_pairs() const {
 121   // Assert that the register mask contains only bit pairs.
 122   assert(valid_watermarks(), "sanity");
 123   for (int i = _lwm; i <= _hwm; i++) {


 158         i++;                       // Skip iteration forward
 159         if (i > _hwm || _A[i] != 1)
 160           return false; // Require 1 lo bit in next word
 161       }
 162     }
 163   }
 164   // True for both the empty mask and for a bit pair
 165   return true;
 166 }
 167 
 168 // Test for a single adjacent set of ideal register's size.
 169 bool RegMask::is_bound(uint ireg) const {
 170   if (is_vector(ireg)) {
 171     if (is_bound_set(num_registers(ireg)))
 172       return true;
 173   } else if (is_bound1() || is_bound_pair()) {
 174     return true;
 175   }
 176   return false;
 177 }
 178 // Check that whether given reg number with size is valid
 179 // for current regmask, where reg is the highest number.
 180 bool RegMask::is_valid_reg(OptoReg::Name reg, const int size) const {
 181   for (int i = 0; i < size; i++) {
 182     if (!Member(reg - i)) {
 183       return false;
 184     }
 185   }
 186   return true;
 187 }
 188 
 189 // only indicies of power 2 are accessed, so index 3 is only filled in for storage.
 190 static int low_bits[5] = { 0x55555555, 0x11111111, 0x01010101, 0x00000000, 0x00010001 };
 191 
 192 // Find the lowest-numbered register set in the mask.  Return the
 193 // HIGHEST register number in the set, or BAD if no sets.
 194 // Works also for size 1.
 195 OptoReg::Name RegMask::find_first_set(LRG &lrg, const int size) const {
 196   if (lrg.is_scalable()) {
 197     // For scalable vector register, regmask is SlotsPerVecA bits aligned.
 198     assert(is_aligned_sets(SlotsPerVecA), "mask is not aligned, adjacent sets");
 199   } else {
 200     assert(is_aligned_sets(size), "mask is not aligned, adjacent sets");
 201   }
 202   assert(valid_watermarks(), "sanity");
 203   for (int i = _lwm; i <= _hwm; i++) {
 204     if (_A[i]) {                // Found some bits
 205       // Convert to bit number, return hi bit in pair
 206       return OptoReg::Name((i<<_LogWordBits) + find_lowest_bit(_A[i]) + (size - 1));
 207     }
 208   }
 209   return OptoReg::Bad;
 210 }
 211 
 212 // Clear out partial bits; leave only aligned adjacent bit pairs
 213 void RegMask::clear_to_sets(const int size) {
 214   if (size == 1) return;
 215   assert(2 <= size && size <= 16, "update low bits table");
 216   assert(is_power_of_2(size), "sanity");
 217   assert(valid_watermarks(), "sanity");
 218   int low_bits_mask = low_bits[size>>2];
 219   for (int i = _lwm; i <= _hwm; i++) {
 220     int bits = _A[i];
 221     int sets = (bits & low_bits_mask);


 261         }
 262       }
 263     }
 264     _A[i] = sets;
 265   }
 266   assert(is_aligned_sets(size), "mask is not aligned, adjacent sets");
 267 }
 268 
 269 // Assert that the register mask contains only bit sets.
 270 bool RegMask::is_aligned_sets(const int size) const {
 271   if (size == 1) return true;
 272   assert(2 <= size && size <= 16, "update low bits table");
 273   assert(is_power_of_2(size), "sanity");
 274   int low_bits_mask = low_bits[size>>2];
 275   assert(valid_watermarks(), "sanity");
 276   for (int i = _lwm; i <= _hwm; i++) {
 277     int bits = _A[i];
 278     while (bits) {              // Check bits for pairing
 279       int bit = bits & -bits;   // Extract low bit
 280       // Low bit is not odd means its mis-aligned.
 281       if ((bit & low_bits_mask) == 0) {
 282         return false;
 283       }
 284       // Do extra work since (bit << size) may overflow.
 285       int hi_bit = bit << (size-1); // high bit
 286       int set = hi_bit + ((hi_bit-1) & ~(bit-1));
 287       // Check for aligned adjacent bits in this set
 288       if ((bits & set) != set) {
 289         return false;
 290       }
 291       bits -= set;  // Remove this set
 292     }
 293   }
 294   return true;
 295 }
 296 
 297 // Return TRUE if the mask contains one adjacent set of bits and no other bits.
 298 // Works also for size 1.
 299 int RegMask::is_bound_set(const int size) const {
 300   if (is_AllStack()) return false;
 301   assert(1 <= size && size <= 16, "update low bits table");
 302   assert(valid_watermarks(), "sanity");
 303   int bit = -1;                 // Set to hold the one bit allowed
 304   for (int i = _lwm; i <= _hwm; i++) {
 305     if (_A[i] ) {               // Found some bits
 306       if (bit != -1)
 307        return false;            // Already had bits, so fail
 308       bit = _A[i] & -_A[i];     // Extract low bit from mask
 309       int hi_bit = bit << (size-1); // high bit
 310       if (hi_bit != 0) {        // Bit set stays in same word?


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