[builtins] Make Math.max and Math.min fast by default.

src/x64/builtins-x64.cc

 // Copyright 2012 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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 1462 matching lines @@
   __ movp(rdx, rdi);
   // Run the native code for the Array function called as a normal function.
   // tail call a stub
   __ LoadRoot(rbx, Heap::kUndefinedValueRootIndex);
   ArrayConstructorStub stub(masm->isolate());
   __ TailCallStub(&stub);
 }
 
 
 // static
+void Builtins::Generate_MathMaxMin(MacroAssembler* masm, MathMaxMinKind kind) {
+  // ----------- S t a t e -------------
+  //  -- rax                 : number of arguments
+  //  -- rsp[0]              : return address
+  //  -- rsp[(argc - n) * 8] : arg[n] (zero-based)
+  //  -- rsp[(argc + 1) * 8] : receiver
+  // -----------------------------------
+  Condition const cc = (kind == MathMaxMinKind::kMin) ? below : above;
+  Heap::RootListIndex const root_index =
+      (kind == MathMaxMinKind::kMin) ? Heap::kInfinityValueRootIndex
+                                     : Heap::kMinusInfinityValueRootIndex;
+  XMMRegister const reg = (kind == MathMaxMinKind::kMin) ? xmm1 : xmm0;
+
+  // Load the accumulator with the default return value (either -Infinity or
+  // +Infinity), with the tagged value in rdx and the double value in xmm0.
+  __ LoadRoot(rdx, root_index);
+  __ Movsd(xmm0, FieldOperand(rdx, HeapNumber::kValueOffset));
+  __ Move(rcx, rax);
+
+  Label done_loop, loop;
+  __ bind(&loop);
+  {
+    // Check if all parameters done.
+    __ testp(rcx, rcx);
+    __ j(zero, &done_loop);
+
+    // Load the next parameter tagged value into rbx.
+    __ movp(rbx, Operand(rsp, rcx, times_pointer_size, 0));
+
+    // Load the double value of the parameter into xmm1, maybe converting the
+    // parameter to a number first using the ToNumberStub if necessary.
+    Label convert, convert_smi, convert_number, done_convert;
+    __ bind(&convert);
+    __ JumpIfSmi(rbx, &convert_smi);
+    __ JumpIfRoot(FieldOperand(rbx, HeapObject::kMapOffset),
+                  Heap::kHeapNumberMapRootIndex, &convert_number);
+    {
+      // Parameter is not a Number, use the ToNumberStub to convert it.
+      FrameScope scope(masm, StackFrame::INTERNAL);
+      __ Integer32ToSmi(rax, rax);
+      __ Integer32ToSmi(rcx, rcx);
+      __ Push(rax);
+      __ Push(rcx);
+      __ Push(rdx);
+      __ movp(rax, rbx);
+      ToNumberStub stub(masm->isolate());
+      __ CallStub(&stub);
+      __ movp(rbx, rax);
+      __ Pop(rdx);
+      __ Pop(rcx);
+      __ Pop(rax);
+      {
+        // Restore the double accumulator value (xmm0).
+        Label restore_smi, done_restore;
+        __ JumpIfSmi(rdx, &restore_smi, Label::kNear);
+        __ Movsd(xmm0, FieldOperand(rdx, HeapNumber::kValueOffset));
+        __ jmp(&done_restore, Label::kNear);
+        __ bind(&restore_smi);
+        __ SmiToDouble(xmm0, rdx);
+        __ bind(&done_restore);
+      }
+      __ SmiToInteger32(rcx, rcx);
+      __ SmiToInteger32(rax, rax);
+    }
+    __ jmp(&convert);
+    __ bind(&convert_number);
+    __ Movsd(xmm1, FieldOperand(rbx, HeapNumber::kValueOffset));
+    __ jmp(&done_convert, Label::kNear);
+    __ bind(&convert_smi);
+    __ SmiToDouble(xmm1, rbx);
+    __ bind(&done_convert);
+
+    // Perform the actual comparison with the accumulator value on the left hand
+    // side (xmm0) and the next parameter value on the right hand side (xmm1).
+    Label compare_equal, compare_nan, compare_swap, done_compare;
+    __ Ucomisd(xmm0, xmm1);
+    __ j(parity_even, &compare_nan, Label::kNear);
+    __ j(cc, &done_compare, Label::kNear);
+    __ j(equal, &compare_equal, Label::kNear);
+
+    // Result is on the right hand side.
+    __ bind(&compare_swap);
+    __ Movaps(xmm0, xmm1);
+    __ Move(rdx, rbx);
+    __ jmp(&done_compare, Label::kNear);
+
+    // At least one side is NaN, which means that the result will be NaN too.
+    __ bind(&compare_nan);
+    __ LoadRoot(rdx, Heap::kNanValueRootIndex);
+    __ Movsd(xmm0, FieldOperand(rdx, HeapNumber::kValueOffset));
+    __ jmp(&done_compare, Label::kNear);
+
+    // Left and right hand side are equal, check for -0 vs. +0.
+    __ bind(&compare_equal);
+    __ Movmskpd(kScratchRegister, reg);
+    __ testl(kScratchRegister, Immediate(1));
+    __ j(not_zero, &compare_swap);
+
+    __ bind(&done_compare);
+    __ decp(rcx);
+    __ jmp(&loop);
+  }
+
+  __ bind(&done_loop);
+  __ PopReturnAddressTo(rcx);
+  __ leap(rsp, Operand(rsp, rax, times_pointer_size, kPointerSize));
+  __ PushReturnAddressFrom(rcx);
+  __ movp(rax, rdx);
+  __ Ret();
+}
+
+// static
 void Builtins::Generate_NumberConstructor(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rax                 : number of arguments
   //  -- rdi                 : constructor function
   //  -- rsp[0]              : return address
   //  -- rsp[(argc - n) * 8] : arg[n] (zero-based)
   //  -- rsp[(argc + 1) * 8] : receiver
   // -----------------------------------
 
   // 1. Load the first argument into rax and get rid of the rest (including the
@@ skipping 1259 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64