[compiler] Turn InstructionBlock bool members into bitfield

Change-Id: I19b06e8590e7555e64b3ad59b2f0defe504f87ce
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2933502Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75202}

src/compiler/backend/instruction.cc

@@ -607,7 +607,12 @@ InstructionBlock::InstructionBlock(Zone* zone, RpoNumber rpo_number,
       loop_end_(loop_end),
       dominator_(dominator),
       deferred_(deferred),
-      handler_(handler) {}
+      handler_(handler),
+      switch_target_(false),
+      alignment_(false),
+      needs_frame_(false),
+      must_construct_frame_(false),
+      must_deconstruct_frame_(false) {}
 
 size_t InstructionBlock::PredecessorIndexOf(RpoNumber rpo_number) const {
   size_t j = 0;

src/compiler/backend/instruction.h

@@ -1585,13 +1585,13 @@ class V8_EXPORT_PRIVATE InstructionBlock final
   RpoNumber dominator_;
   int32_t code_start_;   // start index of arch-specific code.
   int32_t code_end_ = -1;     // end index of arch-specific code.
-  const bool deferred_;       // Block contains deferred code.
-  bool handler_;              // Block is a handler entry point.
-  bool switch_target_ = false;
-  bool alignment_ = false;  // insert alignment before this block
-  bool needs_frame_ = false;
-  bool must_construct_frame_ = false;
-  bool must_deconstruct_frame_ = false;
+  const bool deferred_ : 1;   // Block contains deferred code.
+  bool handler_ : 1;          // Block is a handler entry point.
+  bool switch_target_ : 1;
+  bool alignment_ : 1;  // insert alignment before this block
+  bool needs_frame_ : 1;
+  bool must_construct_frame_ : 1;
+  bool must_deconstruct_frame_ : 1;
 };
 
 class InstructionSequence;