X87: [builtins] Make Math.max and Math.min fast by default.

src/x87/builtins-x87.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_X87
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 1398 matching lines @@
 
   // Run the native code for the Array function called as a normal function.
   // tail call a stub
   __ mov(ebx, masm->isolate()->factory()->undefined_value());
   ArrayConstructorStub stub(masm->isolate());
   __ TailCallStub(&stub);
 }
 
 
 // static
+void Builtins::Generate_MathMaxMin(MacroAssembler* masm, MathMaxMinKind kind) {
+  // ----------- S t a t e -------------
+  //  -- eax                 : number of arguments
+  //  -- esp[0]              : return address
+  //  -- esp[(argc - n) * 8] : arg[n] (zero-based)
+  //  -- esp[(argc + 1) * 8] : receiver
+  // -----------------------------------
+  Condition const cc = (kind == MathMaxMinKind::kMin) ? below : above;
+  Heap::RootListIndex const root_index =
+      (kind == MathMaxMinKind::kMin) ? Heap::kInfinityValueRootIndex
+                                     : Heap::kMinusInfinityValueRootIndex;
+  const int reg_sel = (kind == MathMaxMinKind::kMin) ? 1 : 0;
+
+  // Load the accumulator with the default return value (either -Infinity or
+  // +Infinity), with the tagged value in edx and the double value in stx_0.
+  __ LoadRoot(edx, root_index);
+  __ fld_d(FieldOperand(edx, HeapNumber::kValueOffset));
+  __ Move(ecx, eax);
+
+  Label done_loop, loop;
+  __ bind(&loop);
+  {
+    // Check if all parameters done.
+    __ test(ecx, ecx);
+    __ j(zero, &done_loop);
+
+    // Load the next parameter tagged value into ebx.
+    __ mov(ebx, Operand(esp, ecx, times_pointer_size, 0));
+
+    // Load the double value of the parameter into stx_1, maybe converting the
+    // parameter to a number first using the ToNumberStub if necessary.
+    Label convert, convert_smi, convert_number, done_convert;
+    __ bind(&convert);
+    __ JumpIfSmi(ebx, &convert_smi);
+    __ JumpIfRoot(FieldOperand(ebx, HeapObject::kMapOffset),
+                  Heap::kHeapNumberMapRootIndex, &convert_number);
+    {
+      // Parameter is not a Number, use the ToNumberStub to convert it.
+      FrameScope scope(masm, StackFrame::INTERNAL);
+      __ SmiTag(eax);
+      __ SmiTag(ecx);
+      __ Push(eax);
+      __ Push(ecx);
+      __ Push(edx);
+      __ mov(eax, ebx);
+      ToNumberStub stub(masm->isolate());
+      __ CallStub(&stub);
+      __ mov(ebx, eax);
+      __ Pop(edx);
+      __ Pop(ecx);
+      __ Pop(eax);
+      {
+        // Restore the double accumulator value (stX_0).
+        Label restore_smi, done_restore;
+        __ JumpIfSmi(edx, &restore_smi, Label::kNear);
+        __ fld_d(FieldOperand(edx, HeapNumber::kValueOffset));
+        __ jmp(&done_restore, Label::kNear);
+        __ bind(&restore_smi);
+        __ SmiUntag(edx);
+        __ push(edx);
+        __ fild_s(Operand(esp, 0));
+        __ pop(edx);
+        __ SmiTag(edx);
+        __ bind(&done_restore);
+      }
+      __ SmiUntag(ecx);
+      __ SmiUntag(eax);
+    }
+    __ jmp(&convert);
+    __ bind(&convert_number);
+    // Load another value into stx_1
+    __ fld_d(FieldOperand(ebx, HeapNumber::kValueOffset));
+    __ fxch();
+    __ jmp(&done_convert, Label::kNear);
+    __ bind(&convert_smi);
+    __ SmiUntag(ebx);
+    __ push(ebx);
+    __ fild_s(Operand(esp, 0));
+    __ pop(ebx);
+    __ fxch();
+    __ SmiTag(ebx);
+    __ bind(&done_convert);
+
+    // Perform the actual comparison with the accumulator value on the left hand
+    // side (stx_0) and the next parameter value on the right hand side (stx_1).
+    Label compare_equal, compare_nan, compare_swap, done_compare;
+
+    // Duplicates the 2 float data for FCmp
+    __ fld(1);
+    __ fld(1);
+    __ FCmp();
+    __ 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(stx_0).
+    __ bind(&compare_swap);
+    __ fxch();
+    __ mov(edx, ebx);
+    __ jmp(&done_compare, Label::kNear);
+
+    // At least one side is NaN, which means that the result will be NaN too.
+    __ bind(&compare_nan);
+    // Set the result on the right hand side (stx_0) to nan
+    __ fstp(0);
+    __ LoadRoot(edx, Heap::kNanValueRootIndex);
+    __ fld_d(FieldOperand(edx, HeapNumber::kValueOffset));
+    __ jmp(&done_compare, Label::kNear);
+
+    // Left and right hand side are equal, check for -0 vs. +0.
+    __ bind(&compare_equal);
+    // Check the sign of the value in reg_sel
+    __ fld(reg_sel);
+    __ FXamSign();
+    __ j(not_zero, &compare_swap);
+
+    __ bind(&done_compare);
+    // The right result is on the right hand side(stx_0)
+    // and can remove the useless stx_1 now.
+    __ fxch();
+    __ fstp(0);
+    __ dec(ecx);
+    __ jmp(&loop);
+  }
+
+  __ bind(&done_loop);
+  __ PopReturnAddressTo(ecx);
+  __ lea(esp, Operand(esp, eax, times_pointer_size, kPointerSize));
+  __ PushReturnAddressFrom(ecx);
+  __ mov(eax, edx);
+  __ Ret();
+}
+
+// static
 void Builtins::Generate_NumberConstructor(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- eax                 : number of arguments
   //  -- edi                 : constructor function
   //  -- esp[0]              : return address
   //  -- esp[(argc - n) * 4] : arg[n] (zero-based)
   //  -- esp[(argc + 1) * 4] : receiver
   // -----------------------------------
 
   // 1. Load the first argument into eax and get rid of the rest (including the
@@ skipping 1253 matching lines @@
 
   __ bind(&ok);
   __ ret(0);
 }
 
 #undef __
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87