Reland r22247 "ARM64: Use UntagSmi helpers and clean up assertions."

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

Index: src/arm64/macro-assembler-arm64-inl.h
diff --git a/src/arm64/macro-assembler-arm64-inl.h b/src/arm64/macro-assembler-arm64-inl.h
index 3ce4855b8a1b004065acc93553fa33f42ef1291b..4a93053811688a362a741d529e0b93c052ae295a 100644
--- a/src/arm64/macro-assembler-arm64-inl.h
+++ b/src/arm64/macro-assembler-arm64-inl.h
@@ -1308,6 +1308,8 @@ void MacroAssembler::InitializeRootRegister() {
 
 
 void MacroAssembler::SmiTag(Register dst, Register src) {
+  STATIC_ASSERT(kXRegSizeInBits ==
+                static_cast<unsigned>(kSmiShift + kSmiValueSize));
   ASSERT(dst.Is64Bits() && src.Is64Bits());
   Lsl(dst, src, kSmiShift);
 }
@@ -1317,6 +1319,8 @@ void MacroAssembler::SmiTag(Register smi) { SmiTag(smi, smi); }
 
 
 void MacroAssembler::SmiUntag(Register dst, Register src) {
+  STATIC_ASSERT(kXRegSizeInBits ==
+                static_cast<unsigned>(kSmiShift + kSmiValueSize));
   ASSERT(dst.Is64Bits() && src.Is64Bits());
   if (FLAG_enable_slow_asserts) {
     AssertSmi(src);
@@ -1351,13 +1355,17 @@ void MacroAssembler::SmiUntagToFloat(FPRegister dst,
 
 
 void MacroAssembler::SmiTagAndPush(Register src) {
-  STATIC_ASSERT((kSmiShift == 32) && (kSmiTag == 0));
+  STATIC_ASSERT((static_cast<unsigned>(kSmiShift) == kWRegSizeInBits) &&
+                (static_cast<unsigned>(kSmiValueSize) == kWRegSizeInBits) &&
+                (kSmiTag == 0));
   Push(src.W(), wzr);
 }
 
 
 void MacroAssembler::SmiTagAndPush(Register src1, Register src2) {
-  STATIC_ASSERT((kSmiShift == 32) && (kSmiTag == 0));
+  STATIC_ASSERT((static_cast<unsigned>(kSmiShift) == kWRegSizeInBits) &&
+                (static_cast<unsigned>(kSmiValueSize) == kWRegSizeInBits) &&
+                (kSmiTag == 0));
   Push(src1.W(), wzr, src2.W(), wzr);
 }