ARM64: Enable shorten-64-to-32 warning

src/arm64/instructions-arm64.cc

Index: src/arm64/instructions-arm64.cc
diff --git a/src/arm64/instructions-arm64.cc b/src/arm64/instructions-arm64.cc
index 7a5effe427847582dd71e3bff9e14a29e97edca2..814ead318c749960cebcd3ace5767f36cfa87bb1 100644
--- a/src/arm64/instructions-arm64.cc
+++ b/src/arm64/instructions-arm64.cc
@@ -93,9 +93,9 @@ static uint64_t RepeatBitsAcrossReg(unsigned reg_size,
 // met.
 uint64_t Instruction::ImmLogical() {
   unsigned reg_size = SixtyFourBits() ? kXRegSizeInBits : kWRegSizeInBits;
-  int64_t n = BitN();
-  int64_t imm_s = ImmSetBits();
-  int64_t imm_r = ImmRotate();
+  int32_t n = BitN();
+  int32_t imm_s = ImmSetBits();
+  int32_t imm_r = ImmRotate();
 
   // An integer is constructed from the n, imm_s and imm_r bits according to
   // the following table:
@@ -211,7 +211,7 @@ Instruction* Instruction::ImmPCOffsetTarget() {
 
 
 bool Instruction::IsValidImmPCOffset(ImmBranchType branch_type,
-                                     int32_t offset) {
+                                     ptrdiff_t offset) {
   return is_intn(offset, ImmBranchRangeBitwidth(branch_type));
 }
 
@@ -242,7 +242,7 @@ void Instruction::SetPCRelImmTarget(Instruction* target) {
   ptrdiff_t target_offset = DistanceTo(target);
   Instr imm;
   if (Instruction::IsValidPCRelOffset(target_offset)) {
-    imm = Assembler::ImmPCRelAddress(target_offset);
+    imm = Assembler::ImmPCRelAddress(static_cast<int>(target_offset));
     SetInstructionBits(Mask(~ImmPCRel_mask) | imm);
   } else {
     PatchingAssembler patcher(this,
@@ -254,9 +254,11 @@ void Instruction::SetPCRelImmTarget(Instruction* target) {
 
 void Instruction::SetBranchImmTarget(Instruction* target) {
   DCHECK(IsAligned(DistanceTo(target), kInstructionSize));
+  DCHECK(IsValidImmPCOffset(BranchType(),
+                            DistanceTo(target) >> kInstructionSizeLog2));
+  int offset = static_cast<int>(DistanceTo(target) >> kInstructionSizeLog2);
   Instr branch_imm = 0;
   uint32_t imm_mask = 0;
-  ptrdiff_t offset = DistanceTo(target) >> kInstructionSizeLog2;
   switch (BranchType()) {
     case CondBranchType: {
       branch_imm = Assembler::ImmCondBranch(offset);
@@ -287,9 +289,9 @@ void Instruction::SetBranchImmTarget(Instruction* target) {
 void Instruction::SetUnresolvedInternalReferenceImmTarget(Instruction* target) {
   DCHECK(IsUnresolvedInternalReference());
   DCHECK(IsAligned(DistanceTo(target), kInstructionSize));
-
-  ptrdiff_t target_offset = DistanceTo(target) >> kInstructionSizeLog2;
-  DCHECK(is_int32(target_offset));
+  DCHECK(is_int32(DistanceTo(target) >> kInstructionSizeLog2));
+  int32_t target_offset =
+      static_cast<int32_t>(DistanceTo(target) >> kInstructionSizeLog2);
   uint32_t high16 = unsigned_bitextract_32(31, 16, target_offset);
   uint32_t low16 = unsigned_bitextract_32(15, 0, target_offset);
 
@@ -302,8 +304,9 @@ void Instruction::SetUnresolvedInternalReferenceImmTarget(Instruction* target) {
 void Instruction::SetImmLLiteral(Instruction* source) {
   DCHECK(IsLdrLiteral());
   DCHECK(IsAligned(DistanceTo(source), kInstructionSize));
-  ptrdiff_t offset = DistanceTo(source) >> kLoadLiteralScaleLog2;
-  Instr imm = Assembler::ImmLLiteral(offset);
+  DCHECK(Assembler::IsImmLLiteral(DistanceTo(source)));
+  Instr imm = Assembler::ImmLLiteral(
+      static_cast<int>(DistanceTo(source) >> kLoadLiteralScaleLog2));
   Instr mask = ImmLLiteral_mask;
 
   SetInstructionBits(Mask(~mask) | imm);