[arm64] Use CBZ in binary switch.

When comparing with zero, we can generate a CBZ instruction instead of a
CMP+B. If we teach TurboAssembler::JumpIfEqual() to do it then we can do it
in code generated for binary switches.

Change-Id: I39a045ed666fd6569bf9c9f6be28c4efbeeb01a9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1836254Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/master@{#64094}

src/codegen/arm64/macro-assembler-arm64-inl.h

@@ -1055,13 +1055,11 @@ void TurboAssembler::JumpIfSmi(Register value, Label* smi_label,
 }
 
 void TurboAssembler::JumpIfEqual(Register x, int32_t y, Label* dest) {
-  Cmp(x, y);
-  B(eq, dest);
+  CompareAndBranch(x, y, eq, dest);
 }
 
 void TurboAssembler::JumpIfLessThan(Register x, int32_t y, Label* dest) {
-  Cmp(x, y);
-  B(lt, dest);
+  CompareAndBranch(x, y, lt, dest);
 }
 
 void MacroAssembler::JumpIfNotSmi(Register value, Label* not_smi_label) {
@@ -1201,7 +1199,7 @@ void TurboAssembler::DropSlots(int64_t count) {
 
 void TurboAssembler::PushArgument(const Register& arg) { Push(padreg, arg); }
 
-void MacroAssembler::CompareAndBranch(const Register& lhs, const Operand& rhs,
+void TurboAssembler::CompareAndBranch(const Register& lhs, const Operand& rhs,
                                       Condition cond, Label* label) {
   if (rhs.IsImmediate() && (rhs.ImmediateValue() == 0) &&
       ((cond == eq) || (cond == ne))) {
@@ -1216,7 +1214,7 @@ void MacroAssembler::CompareAndBranch(const Register& lhs, const Operand& rhs,
   }
 }
 
-void MacroAssembler::CompareTaggedAndBranch(const Register& lhs,
+void TurboAssembler::CompareTaggedAndBranch(const Register& lhs,
                                             const Operand& rhs, Condition cond,
                                             Label* label) {
   if (COMPRESS_POINTERS_BOOL) {

src/codegen/arm64/macro-assembler-arm64.h

@@ -844,6 +844,13 @@ class V8_EXPORT_PRIVATE TurboAssembler : public TurboAssemblerBase {
   void CheckPageFlag(const Register& object, int mask, Condition cc,
                      Label* condition_met);
 
+  // Compare a register with an operand, and branch to label depending on the
+  // condition. May corrupt the status flags.
+  inline void CompareAndBranch(const Register& lhs, const Operand& rhs,
+                               Condition cond, Label* label);
+  inline void CompareTaggedAndBranch(const Register& lhs, const Operand& rhs,
+                                     Condition cond, Label* label);
+
   // Test the bits of register defined by bit_pattern, and branch if ANY of
   // those bits are set. May corrupt the status flags.
   inline void TestAndBranchIfAnySet(const Register& reg,
@@ -1644,13 +1651,6 @@ class V8_EXPORT_PRIVATE MacroAssembler : public TurboAssembler {
   // be aligned to 16 bytes.
   void PeekPair(const CPURegister& dst1, const CPURegister& dst2, int offset);
 
-  // Compare a register with an operand, and branch to label depending on the
-  // condition. May corrupt the status flags.
-  inline void CompareAndBranch(const Register& lhs, const Operand& rhs,
-                               Condition cond, Label* label);
-  inline void CompareTaggedAndBranch(const Register& lhs, const Operand& rhs,
-                                     Condition cond, Label* label);
-
   // Insert one or more instructions into the instruction stream that encode
   // some caller-defined data. The instructions used will be executable with no
   // side effects.