1399 if (supports_popcnt()) {
1400 if (FLAG_IS_DEFAULT(UsePopCountInstruction)) {
1401 UsePopCountInstruction = true;
1402 }
1403 } else if (UsePopCountInstruction) {
1404 warning("POPCNT instruction is not available on this CPU");
1405 FLAG_SET_DEFAULT(UsePopCountInstruction, false);
1406 }
1407
1408 // Use fast-string operations if available.
1409 if (supports_erms()) {
1410 if (FLAG_IS_DEFAULT(UseFastStosb)) {
1411 UseFastStosb = true;
1412 }
1413 } else if (UseFastStosb) {
1414 warning("fast-string operations are not available on this CPU");
1415 FLAG_SET_DEFAULT(UseFastStosb, false);
1416 }
1417
1418 // Use XMM/YMM MOVDQU instruction for Object Initialization
1419 if (!UseFastStosb && UseSSE >= 2 && UseUnalignedLoadStores) {
1420 if (FLAG_IS_DEFAULT(UseXMMForObjInit)) {
1421 UseXMMForObjInit = true;
1422 }
1423 } else if (UseXMMForObjInit) {
1424 warning("UseXMMForObjInit requires SSE2 and unaligned load/stores. Feature is switched off.");
1425 FLAG_SET_DEFAULT(UseXMMForObjInit, false);
1426 }
1427
1428 #ifdef COMPILER2
1429 if (FLAG_IS_DEFAULT(AlignVector)) {
1430 // Modern processors allow misaligned memory operations for vectors.
1431 AlignVector = !UseUnalignedLoadStores;
1432 }
1433 #endif // COMPILER2
1434
1435 if (FLAG_IS_DEFAULT(AllocatePrefetchInstr)) {
1436 if (AllocatePrefetchInstr == 3 && !supports_3dnow_prefetch()) {
1437 FLAG_SET_DEFAULT(AllocatePrefetchInstr, 0);
1438 } else if (!supports_sse() && supports_3dnow_prefetch()) {
1439 FLAG_SET_DEFAULT(AllocatePrefetchInstr, 3);
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1399 if (supports_popcnt()) {
1400 if (FLAG_IS_DEFAULT(UsePopCountInstruction)) {
1401 UsePopCountInstruction = true;
1402 }
1403 } else if (UsePopCountInstruction) {
1404 warning("POPCNT instruction is not available on this CPU");
1405 FLAG_SET_DEFAULT(UsePopCountInstruction, false);
1406 }
1407
1408 // Use fast-string operations if available.
1409 if (supports_erms()) {
1410 if (FLAG_IS_DEFAULT(UseFastStosb)) {
1411 UseFastStosb = true;
1412 }
1413 } else if (UseFastStosb) {
1414 warning("fast-string operations are not available on this CPU");
1415 FLAG_SET_DEFAULT(UseFastStosb, false);
1416 }
1417
1418 // Use XMM/YMM MOVDQU instruction for Object Initialization
1419 if (UseSSE >= 2 && UseUnalignedLoadStores) {
1420 if (FLAG_IS_DEFAULT(UseXMMForObjInit)) {
1421 UseXMMForObjInit = true;
1422 }
1423 } else if (UseXMMForObjInit) {
1424 warning("UseXMMForObjInit requires SSE2 and unaligned load/stores. Feature is switched off.");
1425 FLAG_SET_DEFAULT(UseXMMForObjInit, false);
1426 }
1427
1428 #ifdef COMPILER2
1429 if (FLAG_IS_DEFAULT(AlignVector)) {
1430 // Modern processors allow misaligned memory operations for vectors.
1431 AlignVector = !UseUnalignedLoadStores;
1432 }
1433 #endif // COMPILER2
1434
1435 if (FLAG_IS_DEFAULT(AllocatePrefetchInstr)) {
1436 if (AllocatePrefetchInstr == 3 && !supports_3dnow_prefetch()) {
1437 FLAG_SET_DEFAULT(AllocatePrefetchInstr, 0);
1438 } else if (!supports_sse() && supports_3dnow_prefetch()) {
1439 FLAG_SET_DEFAULT(AllocatePrefetchInstr, 3);
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