ARM64: Fix some signed-unsigned comparisons from cdc43bc5 (r28412).

These trigger warnings on cross-builds under GCC.

BUG=

Review URL: https://codereview.chromium.org/1151463002

Cr-Commit-Position: refs/heads/master@{#28509}

src/arm64/assembler-arm64-inl.h

@@ -867,8 +867,8 @@ bool RelocInfo::IsPatchedReturnSequence() {
   // See arm64/debug-arm64.cc BreakLocation::SetDebugBreakAtReturn().
   Instruction* i1 = reinterpret_cast<Instruction*>(pc_);
   Instruction* i2 = i1->following();
-  return i1->IsLdrLiteralX() && (i1->Rt() == ip0.code()) &&
-         i2->IsBranchAndLinkToRegister() && (i2->Rn() == ip0.code());
+  return i1->IsLdrLiteralX() && (i1->Rt() == kIp0Code) &&
+         i2->IsBranchAndLinkToRegister() && (i2->Rn() == kIp0Code);
 }
 
 

src/arm64/assembler-arm64.cc

@@ -891,12 +891,12 @@ bool Assembler::IsConstantPoolAt(Instruction* instr) {
   // The constant pool marker is made of two instructions. These instructions
   // will never be emitted by the JIT, so checking for the first one is enough:
   // 0: ldr xzr, #<size of pool>
-  bool result = instr->IsLdrLiteralX() && (instr->Rt() == xzr.code());
+  bool result = instr->IsLdrLiteralX() && (instr->Rt() == kZeroRegCode);
 
   // It is still worth asserting the marker is complete.
   // 4: blr xzr
   DCHECK(!result || (instr->following()->IsBranchAndLinkToRegister() &&
-                     instr->following()->Rn() == xzr.code()));
+                     instr->following()->Rn() == kZeroRegCode));
 
   return result;
 }

src/arm64/constants-arm64.h

@@ -84,6 +84,8 @@ const int64_t kXMaxInt = 0x7fffffffffffffffL;
 const int64_t kXMinInt = 0x8000000000000000L;
 const int32_t kWMaxInt = 0x7fffffff;
 const int32_t kWMinInt = 0x80000000;
+const unsigned kIp0Code = 16;
+const unsigned kIp1Code = 17;
 const unsigned kFramePointerRegCode = 29;
 const unsigned kLinkRegCode = 30;
 const unsigned kZeroRegCode = 31;

src/arm64/instructions-arm64.cc

@@ -319,7 +319,7 @@ void Instruction::SetImmLLiteral(Instruction* source) {
 bool InstructionSequence::IsInlineData() const {
   // Inline data is encoded as a single movz instruction which writes to xzr
   // (x31).
-  return IsMovz() && SixtyFourBits() && (Rd() == xzr.code());
+  return IsMovz() && SixtyFourBits() && (Rd() == kZeroRegCode);
   // TODO(all): If we extend ::InlineData() to support bigger data, we need
   // to update this method too.
 }