[mips] Remove alignment in kArchStackSlot

In commit 4a5adb43, mips may allocate a
bit more memory than actually needed, and move the beginning of the
StackSlot in order to have it aligned.

After commit e639eafe, we allocated
the memory that was actually needed, so we do not need extra alignment
anymore.

Change-Id: I4c4c01794ed1d2cc5b8c89196eae6834f0da0b6e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2917578Reviewed-by: Zhao Jiazhong <zhaojiazhong-hf@loongson.cn>
Commit-Queue: Zhao Jiazhong <zhaojiazhong-hf@loongson.cn>
Auto-Submit: Liu yu <liuyu@loongson.cn>
Cr-Commit-Position: refs/heads/master@{#74770}

src/compiler/backend/mips/code-generator-mips.cc

@@ -929,34 +929,13 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
           frame_access_state()->GetFrameOffset(i.InputInt32(0));
       Register base_reg = offset.from_stack_pointer() ? sp : fp;
       __ Addu(i.OutputRegister(), base_reg, Operand(offset.offset()));
-      int alignment = i.InputInt32(1);
-      DCHECK(alignment == 0 || alignment == 4 || alignment == 8 ||
-             alignment == 16);
-      if (FLAG_debug_code && alignment > 0) {
+      if (FLAG_debug_code > 0) {
         // Verify that the output_register is properly aligned
         __ And(kScratchReg, i.OutputRegister(),
                Operand(kSystemPointerSize - 1));
         __ Assert(eq, AbortReason::kAllocationIsNotDoubleAligned, kScratchReg,
                   Operand(zero_reg));
       }
-
-      if (alignment == 2 * kSystemPointerSize) {
-        Label done;
-        __ Addu(kScratchReg, base_reg, Operand(offset.offset()));
-        __ And(kScratchReg, kScratchReg, Operand(alignment - 1));
-        __ BranchShort(&done, eq, kScratchReg, Operand(zero_reg));
-        __ Addu(i.OutputRegister(), i.OutputRegister(), kSystemPointerSize);
-        __ bind(&done);
-      } else if (alignment > 2 * kSystemPointerSize) {
-        Label done;
-        __ Addu(kScratchReg, base_reg, Operand(offset.offset()));
-        __ And(kScratchReg, kScratchReg, Operand(alignment - 1));
-        __ BranchShort(&done, eq, kScratchReg, Operand(zero_reg));
-        __ li(kScratchReg2, alignment);
-        __ Subu(kScratchReg2, kScratchReg2, Operand(kScratchReg));
-        __ Addu(i.OutputRegister(), i.OutputRegister(), kScratchReg2);
-        __ bind(&done);
-      }
       break;
     }
     case kArchWordPoisonOnSpeculation:

src/compiler/backend/mips/instruction-selector-mips.cc

@@ -275,8 +275,7 @@ void InstructionSelector::VisitStackSlot(Node* node) {
   OperandGenerator g(this);
 
   Emit(kArchStackSlot, g.DefineAsRegister(node),
-       sequence()->AddImmediate(Constant(slot)),
-       sequence()->AddImmediate(Constant(alignment)), 0, nullptr);
+       sequence()->AddImmediate(Constant(slot)), 0, nullptr);
 }
 
 void InstructionSelector::VisitAbortCSAAssert(Node* node) {

src/compiler/backend/mips64/code-generator-mips64.cc

@@ -891,34 +891,13 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
           frame_access_state()->GetFrameOffset(i.InputInt32(0));
       Register base_reg = offset.from_stack_pointer() ? sp : fp;
       __ Daddu(i.OutputRegister(), base_reg, Operand(offset.offset()));
-      int alignment = i.InputInt32(1);
-      DCHECK(alignment == 0 || alignment == 4 || alignment == 8 ||
-             alignment == 16);
-      if (FLAG_debug_code && alignment > 0) {
+      if (FLAG_debug_code) {
         // Verify that the output_register is properly aligned
         __ And(kScratchReg, i.OutputRegister(),
                Operand(kSystemPointerSize - 1));
         __ Assert(eq, AbortReason::kAllocationIsNotDoubleAligned, kScratchReg,
                   Operand(zero_reg));
       }
-      if (alignment == 2 * kSystemPointerSize) {
-        Label done;
-        __ Daddu(kScratchReg, base_reg, Operand(offset.offset()));
-        __ And(kScratchReg, kScratchReg, Operand(alignment - 1));
-        __ BranchShort(&done, eq, kScratchReg, Operand(zero_reg));
-        __ Daddu(i.OutputRegister(), i.OutputRegister(), kSystemPointerSize);
-        __ bind(&done);
-      } else if (alignment > 2 * kSystemPointerSize) {
-        Label done;
-        __ Daddu(kScratchReg, base_reg, Operand(offset.offset()));
-        __ And(kScratchReg, kScratchReg, Operand(alignment - 1));
-        __ BranchShort(&done, eq, kScratchReg, Operand(zero_reg));
-        __ li(kScratchReg2, alignment);
-        __ Dsubu(kScratchReg2, kScratchReg2, Operand(kScratchReg));
-        __ Daddu(i.OutputRegister(), i.OutputRegister(), kScratchReg2);
-        __ bind(&done);
-      }
-
       break;
     }
     case kArchWordPoisonOnSpeculation:

src/compiler/backend/mips64/instruction-selector-mips64.cc

@@ -353,8 +353,7 @@ void InstructionSelector::VisitStackSlot(Node* node) {
   OperandGenerator g(this);
 
   Emit(kArchStackSlot, g.DefineAsRegister(node),
-       sequence()->AddImmediate(Constant(slot)),
-       sequence()->AddImmediate(Constant(alignment)), 0, nullptr);
+       sequence()->AddImmediate(Constant(slot)), 0, nullptr);
 }
 
 void InstructionSelector::VisitAbortCSAAssert(Node* node) {