[x64] Remove "fake conditions" which are rarely used

Those conditions are rarely used and not properly supported everywhere.
If needed, we should duplicate methods instead, or pass a
{base::Optional<Condition>}.

This is a follow-up to https://crrev.com/c/3629129.

R=tebbi@chromium.org
CC=sroettger@chromium.org

Bug: v8:12425
Change-Id: Ia67c3d4f575b0f7dd0ae125971959cf68f2fefc7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3629553Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80395}

src/builtins/x64/builtins-x64.cc

@@ -1254,7 +1254,7 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
     Label loop_header;
     Label loop_check;
     __ LoadRoot(kInterpreterAccumulatorRegister, RootIndex::kUndefinedValue);
-    __ j(always, &loop_check, Label::kNear);
+    __ jmp(&loop_check, Label::kNear);
     __ bind(&loop_header);
     // TODO(rmcilroy): Consider doing more than one push per loop iteration.
     __ Push(kInterpreterAccumulatorRegister);

src/codegen/x64/assembler-x64.cc

@@ -1068,15 +1068,8 @@ void Assembler::cdq() {
 }
 
 void Assembler::cmovq(Condition cc, Register dst, Register src) {
-  if (cc == always) {
-    movq(dst, src);
-    return;
-  } else if (cc == never) {
-    return;
-  }
-  // No need to check CpuInfo for CMOV support, it's a required part of the
-  // 64-bit architecture.
-  DCHECK_GE(cc, 0);  // Use mov for unconditional moves.
+  DCHECK_LE(0, cc);  // Check for standard and degenerate 'no_condition'.
+
   EnsureSpace ensure_space(this);
   // Opcode: REX.W 0f 40 + cc /r.
   emit_rex_64(dst, src);
@@ -1086,13 +1079,8 @@ void Assembler::cmovq(Condition cc, Register dst, Register src) {
 }
 
 void Assembler::cmovq(Condition cc, Register dst, Operand src) {
-  if (cc == always) {
-    movq(dst, src);
-    return;
-  } else if (cc == never) {
-    return;
-  }
-  DCHECK_GE(cc, 0);
+  DCHECK_LE(0, cc);  // Check for standard and degenerate 'no_condition'.
+
   EnsureSpace ensure_space(this);
   // Opcode: REX.W 0f 40 + cc /r.
   emit_rex_64(dst, src);
@@ -1102,13 +1090,8 @@ void Assembler::cmovq(Condition cc, Register dst, Operand src) {
 }
 
 void Assembler::cmovl(Condition cc, Register dst, Register src) {
-  if (cc == always) {
-    movl(dst, src);
-    return;
-  } else if (cc == never) {
-    return;
-  }
-  DCHECK_GE(cc, 0);
+  DCHECK_LE(0, cc);  // Check for standard and degenerate 'no_condition'.
+
   EnsureSpace ensure_space(this);
   // Opcode: 0f 40 + cc /r.
   emit_optional_rex_32(dst, src);
@@ -1118,13 +1101,8 @@ void Assembler::cmovl(Condition cc, Register dst, Register src) {
 }
 
 void Assembler::cmovl(Condition cc, Register dst, Operand src) {
-  if (cc == always) {
-    movl(dst, src);
-    return;
-  } else if (cc == never) {
-    return;
-  }
-  DCHECK_GE(cc, 0);
+  DCHECK_LE(0, cc);  // Check for standard and degenerate 'no_condition'.
+
   EnsureSpace ensure_space(this);
   // Opcode: 0f 40 + cc /r.
   emit_optional_rex_32(dst, src);
@@ -1362,12 +1340,6 @@ void Assembler::int3() {
 }
 
 void Assembler::j(Condition cc, Label* L, Label::Distance distance) {
-  if (cc == always) {
-    jmp(L, distance);
-    return;
-  } else if (cc == never) {
-    return;
-  }
   EnsureSpace ensure_space(this);
   DCHECK(is_uint4(cc));
   if (L->is_bound()) {
@@ -1447,12 +1419,6 @@ void Assembler::j(Condition cc, Address entry, RelocInfo::Mode rmode) {
 }
 
 void Assembler::j(Condition cc, Handle<CodeT> target, RelocInfo::Mode rmode) {
-  if (cc == always) {
-    jmp(target, rmode);
-    return;
-  } else if (cc == never) {
-    return;
-  }
   EnsureSpace ensure_space(this);
   DCHECK(is_uint4(cc));
   // 0000 1111 1000 tttn #32-bit disp.
@@ -2150,10 +2116,6 @@ void Assembler::ud2() {
 }
 
 void Assembler::setcc(Condition cc, Register reg) {
-  if (cc > last_condition) {
-    movb(reg, Immediate(cc == always ? 1 : 0));
-    return;
-  }
   EnsureSpace ensure_space(this);
   DCHECK(is_uint4(cc));
   if (!reg.is_byte_register()) {

src/codegen/x64/assembler-x64.h

@@ -83,10 +83,6 @@ enum Condition {
   less_equal = 14,
   greater = 15,
 
-  // Fake conditions that are handled by the
-  // opcodes using them.
-  always = 16,
-  never = 17,
   // aliases
   carry = below,
   not_carry = above_equal,
@@ -94,7 +90,6 @@ enum Condition {
   not_zero = not_equal,
   sign = negative,
   not_sign = positive,
-  last_condition = greater
 };
 
 // Returns the equivalent of !cc.

src/codegen/x64/macro-assembler-x64.cc

@@ -1817,6 +1817,20 @@ void TurboAssembler::Jump(Address destination, RelocInfo::Mode rmode) {
   jmp(kScratchRegister);
 }
 
+void TurboAssembler::Jump(Handle<CodeT> code_object, RelocInfo::Mode rmode) {
+  DCHECK_IMPLIES(
+      options().isolate_independent_code,
+      Builtins::IsIsolateIndependentBuiltin(FromCodeT(*code_object)));
+  if (options().inline_offheap_trampolines) {
+    Builtin builtin = Builtin::kNoBuiltinId;
+    if (isolate()->builtins()->IsBuiltinHandle(code_object, &builtin)) {
+      TailCallBuiltin(builtin);
+      return;
+    }
+  }
+  jmp(code_object, rmode);
+}
+
 void TurboAssembler::Jump(Handle<CodeT> code_object, RelocInfo::Mode rmode,
                           Condition cc) {
   DCHECK_IMPLIES(
@@ -1826,10 +1840,7 @@ void TurboAssembler::Jump(Handle<CodeT> code_object, RelocInfo::Mode rmode,
     Builtin builtin = Builtin::kNoBuiltinId;
     if (isolate()->builtins()->IsBuiltinHandle(code_object, &builtin)) {
       Label skip;
-      if (cc != always) {
-        if (cc == never) return;
       j(NegateCondition(cc), &skip, Label::kNear);
-      }
       TailCallBuiltin(builtin);
       bind(&skip);
       return;

src/codegen/x64/macro-assembler-x64.h

@@ -416,8 +416,8 @@ class V8_EXPORT_PRIVATE TurboAssembler
   void Jump(Address destination, RelocInfo::Mode rmode);
   void Jump(const ExternalReference& reference);
   void Jump(Operand op);
-  void Jump(Handle<CodeT> code_object, RelocInfo::Mode rmode,
-            Condition cc = always);
+  void Jump(Handle<CodeT> code_object, RelocInfo::Mode rmode);
+  void Jump(Handle<CodeT> code_object, RelocInfo::Mode rmode, Condition cc);
 
   void BailoutIfDeoptimized(Register scratch);
   void CallForDeoptimization(Builtin target, int deopt_id, Label* exit,

src/maglev/maglev-ir.cc

@@ -261,6 +261,19 @@ void RegisterEagerDeopt(MaglevCodeGenState* code_gen_state,
   }
 }
 
+void EmitEagerDeopt(MaglevCodeGenState* code_gen_state,
+                    EagerDeoptInfo* deopt_info) {
+  RegisterEagerDeopt(code_gen_state, deopt_info);
+  __ RecordComment("-- Jump to eager deopt");
+  __ jmp(&deopt_info->deopt_entry_label);
+}
+
+template <typename NodeT>
+void EmitEagerDeopt(MaglevCodeGenState* code_gen_state, NodeT* node) {
+  STATIC_ASSERT(NodeT::kProperties.can_eager_deopt());
+  EmitEagerDeopt(code_gen_state, node->eager_deopt_info());
+}
+
 void EmitEagerDeoptIf(Condition cond, MaglevCodeGenState* code_gen_state,
                       EagerDeoptInfo* deopt_info) {
   RegisterEagerDeopt(code_gen_state, deopt_info);
@@ -1148,7 +1161,7 @@ void Deopt::AllocateVreg(MaglevVregAllocationState* vreg_state,
                          const ProcessingState& state) {}
 void Deopt::GenerateCode(MaglevCodeGenState* code_gen_state,
                          const ProcessingState& state) {
-  EmitEagerDeoptIf(always, code_gen_state, this);
+  EmitEagerDeopt(code_gen_state, this);
 }
 
 void Jump::AllocateVreg(MaglevVregAllocationState* vreg_state,