X87: Fix the sqrt precision issue.

src/compiler/x87/code-generator-x87.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/code-generator.h"
 
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/osr.h"
@@ skipping 954 matching lines @@
     }
     case kX87Float64InsertLowWord32: {
       __ sub(esp, Immediate(kDoubleSize));
       __ fstp_d(MemOperand(esp, 0));
       __ mov(MemOperand(esp, 0), i.InputRegister(1));
       __ fld_d(MemOperand(esp, 0));
       __ add(esp, Immediate(kDoubleSize));
       break;
     }
     case kX87Float64Sqrt: {
+      __ X87SetFPUCW(0x027F);
       __ fstp(0);
       __ fld_d(MemOperand(esp, 0));
-#if V8_GLIBC_PREREQ(2, 19)
-      __ push(edx);
-      __ sub(esp, Immediate(2 * kIntSize));
-      __ fnstcw(MemOperand(esp, 4));
-      __ mov(edx, Immediate(0xfeff));
-      __ and_(edx, MemOperand(esp, 4));
-      __ mov(MemOperand(esp, 0), edx);
-      __ fldcw(MemOperand(esp, 0));
-#endif
       __ fsqrt();
-#if V8_GLIBC_PREREQ(2, 19)
-      __ fldcw(MemOperand(esp, 4));
-      __ lea(esp, Operand(esp, 2 * kIntSize));
-      __ pop(edx);
-#endif
       __ lea(esp, Operand(esp, kDoubleSize));
+      __ X87SetFPUCW(0x037F);
       break;
     }
     case kX87Float64Round: {
       RoundingMode mode =
           static_cast<RoundingMode>(MiscField::decode(instr->opcode()));
       if (mode == MiscField::encode(kRoundDown)) {
         __ X87SetRC(0x0400);
       } else {
         __ X87SetRC(0x0c00);
       }
@@ skipping 902 matching lines @@
     int padding_size = last_lazy_deopt_pc_ + space_needed - current_pc;
     __ Nop(padding_size);
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8