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++) { 106 int bits = _A[i]; 107 while (bits) { // Check bits for pairing 108 int bit = bits & -bits; // Extract low bit 109 // Low bit is not odd means its mis-aligned. 110 if ((bit & 0x55555555) == 0) return false; 111 bits -= bit; // Remove bit from mask 112 // Check for aligned adjacent bit 113 if ((bits & (bit<<1)) == 0) return false; 114 bits -= (bit<<1); // Remove other halve of pair 115 } 116 } 117 return true; 118 } 119 120 // Return TRUE if the mask contains a single bit 121 bool RegMask::is_bound1() const { 122 if (is_AllStack()) return false; 123 return Size() == 1; 124 } 125 126 // Return TRUE if the mask contains an adjacent pair of bits and no other bits. 127 bool RegMask::is_bound_pair() const { 128 if (is_AllStack()) return false; 129 int bit = -1; // Set to hold the one bit allowed 130 assert(valid_watermarks(), "sanity"); 131 for (int i = _lwm; i <= _hwm; i++) { 132 if (_A[i]) { // Found some bits 133 if (bit != -1) return false; // Already had bits, so fail 134 bit = _A[i] & -(_A[i]); // Extract 1 bit from mask 135 if ((bit << 1) != 0) { // Bit pair stays in same word? 136 if ((bit | (bit<<1)) != _A[i]) 137 return false; // Require adjacent bit pair and no more bits 138 } else { // Else its a split-pair case 139 if(bit != _A[i]) return false; // Found many bits, so fail 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); 189 for (int j = 1; j < size; j++) { 190 sets = (bits & (sets<<1)); // filter bits which produce whole sets 191 } 192 sets |= (sets>>1); // Smear 1 hi-bit into a set 193 if (size > 2) { 194 sets |= (sets>>2); // Smear 2 hi-bits into a set 195 if (size > 4) { 196 sets |= (sets>>4); // Smear 4 hi-bits into a set 197 if (size > 8) { 198 sets |= (sets>>8); // Smear 8 hi-bits into a set 199 } 200 } 201 } 202 _A[i] = sets; 203 } 204 assert(is_aligned_sets(size), "mask is not aligned, adjacent sets"); 205 } 206 207 // Smear out partial bits to aligned adjacent bit sets 208 void RegMask::smear_to_sets(const int size) { 209 if (size == 1) return; 210 assert(2 <= size && size <= 16, "update low bits table"); 211 assert(is_power_of_2(size), "sanity"); 212 assert(valid_watermarks(), "sanity"); 213 int low_bits_mask = low_bits[size>>2]; 214 for (int i = _lwm; i <= _hwm; i++) { 215 int bits = _A[i]; 216 int sets = 0; 217 for (int j = 0; j < size; j++) { 218 sets |= (bits & low_bits_mask); // collect partial bits 219 bits = bits>>1; 220 } 221 sets |= (sets<<1); // Smear 1 lo-bit into a set 222 if (size > 2) { 223 sets |= (sets<<2); // Smear 2 lo-bits into a set 224 if (size > 4) { 225 sets |= (sets<<4); // Smear 4 lo-bits into a set 226 if (size > 8) { 227 sets |= (sets<<8); // Smear 8 lo-bits into a set 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? 274 int set = hi_bit + ((hi_bit-1) & ~(bit-1)); 275 if (set != _A[i]) 276 return false; // Require adjacent bit set and no more bits 277 } else { // Else its a split-set case 278 if (((-1) & ~(bit-1)) != _A[i]) 279 return false; // Found many bits, so fail 280 i++; // Skip iteration forward and check high part 281 // The lower (32-size) bits should be 0 since it is split case. 282 int clear_bit_size = 32-size; 283 int shift_back_size = 32-clear_bit_size; 284 int set = bit>>clear_bit_size; 285 set = set & -set; // Remove sign extension. 286 set = (((set << size) - 1) >> shift_back_size); 287 if (i > _hwm || _A[i] != set) 288 return false; // Require expected low bits in next word 289 } 290 } 291 } 292 // True for both the empty mask and for a bit set 293 return true; 294 } 295 296 // UP means register only, Register plus stack, or stack only is DOWN 297 bool RegMask::is_UP() const { 298 // Quick common case check for DOWN (any stack slot is legal) 299 if (is_AllStack()) 300 return false; 301 // Slower check for any stack bits set (also DOWN) 302 if (overlap(Matcher::STACK_ONLY_mask)) 303 return false; 304 // Not DOWN, so must be UP 305 return true; 306 } 307 308 // Compute size of register mask in bits 309 uint RegMask::Size() const { 310 uint sum = 0; 311 assert(valid_watermarks(), "sanity"); 312 for (int i = _lwm; i <= _hwm; i++) { 313 sum += population_count((unsigned)_A[i]); 314 } 315 return sum; 316 } 317 318 #ifndef PRODUCT 319 void RegMask::dump(outputStream *st) const { 320 st->print("["); 321 RegMask rm = *this; // Structure copy into local temp 322 323 OptoReg::Name start = rm.find_first_elem(); // Get a register 324 if (OptoReg::is_valid(start)) { // Check for empty mask 325 rm.Remove(start); // Yank from mask 326 OptoReg::dump(start, st); // Print register 327 OptoReg::Name last = start; 328 329 // Now I have printed an initial register. 330 // Print adjacent registers as "rX-rZ" instead of "rX,rY,rZ". 331 // Begin looping over the remaining registers. 332 while (1) { // 333 OptoReg::Name reg = rm.find_first_elem(); // Get a register 334 if (!OptoReg::is_valid(reg)) 335 break; // Empty mask, end loop 336 rm.Remove(reg); // Yank from mask 337 338 if (last+1 == reg) { // See if they are adjacent 339 // Adjacent registers just collect into long runs, no printing. 340 last = reg; 341 } else { // Ending some kind of run 342 if (start == last) { // 1-register run; no special printing 343 } else if (start+1 == last) { 344 st->print(","); // 2-register run; print as "rX,rY" 345 OptoReg::dump(last, st); 346 } else { // Multi-register run; print as "rX-rZ" 347 st->print("-"); 348 OptoReg::dump(last, st); 349 } 350 st->print(","); // Seperate start of new run 351 start = last = reg; // Start a new register run 352 OptoReg::dump(start, st); // Print register 353 } // End of if ending a register run or not 354 } // End of while regmask not empty 355 356 if (start == last) { // 1-register run; no special printing 357 } else if (start+1 == last) { 358 st->print(","); // 2-register run; print as "rX,rY" 359 OptoReg::dump(last, st); 360 } else { // Multi-register run; print as "rX-rZ" 361 st->print("-"); 362 OptoReg::dump(last, st); 363 } 364 if (rm.is_AllStack()) st->print("..."); 365 } 366 st->print("]"); 367 } 368 #endif