MIPS: minor cleanup in macro-assembler.

Fix some dodgy temp-register usage and remove some unnecessary
push/pop's.

BUG=

Review URL: https://codereview.chromium.org/1324553004

Cr-Commit-Position: refs/heads/master@{#30646}

src/mips/macro-assembler-mips.cc

@@ -1225,9 +1225,8 @@ void MacroAssembler::FlushICache(Register address, unsigned instructions) {
   MultiPush(saved_regs);
   AllowExternalCallThatCantCauseGC scope(this);
 
-  // Save to a0 in case address == t0.
   Move(a0, address);
-  PrepareCallCFunction(2, t0);
+  PrepareCallCFunction(2, t8);
 
   li(a1, instructions * kInstrSize);
   CallCFunction(ExternalReference::flush_icache_function(isolate()), 2);
@@ -5150,13 +5149,10 @@ void MacroAssembler::AssertSmi(Register object) {
 void MacroAssembler::AssertString(Register object) {
   if (emit_debug_code()) {
     STATIC_ASSERT(kSmiTag == 0);
-    SmiTst(object, t0);
-    Check(ne, kOperandIsASmiAndNotAString, t0, Operand(zero_reg));
-    push(object);
-    lw(object, FieldMemOperand(object, HeapObject::kMapOffset));
-    lbu(object, FieldMemOperand(object, Map::kInstanceTypeOffset));
-    Check(lo, kOperandIsNotAString, object, Operand(FIRST_NONSTRING_TYPE));
-    pop(object);
+    SmiTst(object, t8);
+    Check(ne, kOperandIsASmiAndNotAString, t8, Operand(zero_reg));
+    GetObjectType(object, t8, t8);
+    Check(lo, kOperandIsNotAString, t8, Operand(FIRST_NONSTRING_TYPE));
   }
 }
 
@@ -5164,13 +5160,10 @@ void MacroAssembler::AssertString(Register object) {
 void MacroAssembler::AssertName(Register object) {
   if (emit_debug_code()) {
     STATIC_ASSERT(kSmiTag == 0);
-    SmiTst(object, t0);
-    Check(ne, kOperandIsASmiAndNotAName, t0, Operand(zero_reg));
-    push(object);
-    lw(object, FieldMemOperand(object, HeapObject::kMapOffset));
-    lbu(object, FieldMemOperand(object, Map::kInstanceTypeOffset));
-    Check(le, kOperandIsNotAName, object, Operand(LAST_NAME_TYPE));
-    pop(object);
+    SmiTst(object, t8);
+    Check(ne, kOperandIsASmiAndNotAName, t8, Operand(zero_reg));
+    GetObjectType(object, t8, t8);
+    Check(le, kOperandIsNotAName, t8, Operand(LAST_NAME_TYPE));
   }
 }
 
@@ -5178,10 +5171,10 @@ void MacroAssembler::AssertName(Register object) {
 void MacroAssembler::AssertFunction(Register object) {
   if (emit_debug_code()) {
     STATIC_ASSERT(kSmiTag == 0);
-    SmiTst(object, t0);
-    Check(ne, kOperandIsASmiAndNotAFunction, t0, Operand(zero_reg));
-    GetObjectType(object, t0, t0);
-    Check(eq, kOperandIsNotAFunction, t0, Operand(JS_FUNCTION_TYPE));
+    SmiTst(object, t8);
+    Check(ne, kOperandIsASmiAndNotAFunction, t8, Operand(zero_reg));
+    GetObjectType(object, t8, t8);
+    Check(eq, kOperandIsNotAFunction, t8, Operand(JS_FUNCTION_TYPE));
   }
 }
 
@@ -5193,11 +5186,9 @@ void MacroAssembler::AssertUndefinedOrAllocationSite(Register object,
     AssertNotSmi(object);
     LoadRoot(scratch, Heap::kUndefinedValueRootIndex);
     Branch(&done_checking, eq, object, Operand(scratch));
-    push(object);
-    lw(object, FieldMemOperand(object, HeapObject::kMapOffset));
+    lw(t8, FieldMemOperand(object, HeapObject::kMapOffset));
     LoadRoot(scratch, Heap::kAllocationSiteMapRootIndex);
-    Assert(eq, kExpectedUndefinedOrCell, object, Operand(scratch));
-    pop(object);
+    Assert(eq, kExpectedUndefinedOrCell, t8, Operand(scratch));
     bind(&done_checking);
   }
 }

src/mips64/macro-assembler-mips64.cc

@@ -1439,9 +1439,8 @@ void MacroAssembler::FlushICache(Register address, unsigned instructions) {
   MultiPush(saved_regs);
   AllowExternalCallThatCantCauseGC scope(this);
 
-  // Save to a0 in case address == a4.
   Move(a0, address);
-  PrepareCallCFunction(2, a4);
+  PrepareCallCFunction(2, t8);
 
   li(a1, instructions * kInstrSize);
   CallCFunction(ExternalReference::flush_icache_function(isolate()), 2);
@@ -5348,13 +5347,10 @@ void MacroAssembler::AssertSmi(Register object) {
 void MacroAssembler::AssertString(Register object) {
   if (emit_debug_code()) {
     STATIC_ASSERT(kSmiTag == 0);
-    SmiTst(object, a4);
-    Check(ne, kOperandIsASmiAndNotAString, a4, Operand(zero_reg));
-    push(object);
-    ld(object, FieldMemOperand(object, HeapObject::kMapOffset));
-    lbu(object, FieldMemOperand(object, Map::kInstanceTypeOffset));
-    Check(lo, kOperandIsNotAString, object, Operand(FIRST_NONSTRING_TYPE));
-    pop(object);
+    SmiTst(object, t8);
+    Check(ne, kOperandIsASmiAndNotAString, t8, Operand(zero_reg));
+    GetObjectType(object, t8, t8);
+    Check(lo, kOperandIsNotAString, t8, Operand(FIRST_NONSTRING_TYPE));
   }
 }
 
@@ -5362,13 +5358,10 @@ void MacroAssembler::AssertString(Register object) {
 void MacroAssembler::AssertName(Register object) {
   if (emit_debug_code()) {
     STATIC_ASSERT(kSmiTag == 0);
-    SmiTst(object, a4);
-    Check(ne, kOperandIsASmiAndNotAName, a4, Operand(zero_reg));
-    push(object);
-    ld(object, FieldMemOperand(object, HeapObject::kMapOffset));
-    lbu(object, FieldMemOperand(object, Map::kInstanceTypeOffset));
-    Check(le, kOperandIsNotAName, object, Operand(LAST_NAME_TYPE));
-    pop(object);
+    SmiTst(object, t8);
+    Check(ne, kOperandIsASmiAndNotAName, t8, Operand(zero_reg));
+    GetObjectType(object, t8, t8);
+    Check(le, kOperandIsNotAName, t8, Operand(LAST_NAME_TYPE));
   }
 }
 
@@ -5376,10 +5369,10 @@ void MacroAssembler::AssertName(Register object) {
 void MacroAssembler::AssertFunction(Register object) {
   if (emit_debug_code()) {
     STATIC_ASSERT(kSmiTag == 0);
-    SmiTst(object, t0);
-    Check(ne, kOperandIsASmiAndNotAFunction, t0, Operand(zero_reg));
-    GetObjectType(object, t0, t0);
-    Check(eq, kOperandIsNotAFunction, t0, Operand(JS_FUNCTION_TYPE));
+    SmiTst(object, t8);
+    Check(ne, kOperandIsASmiAndNotAFunction, t8, Operand(zero_reg));
+    GetObjectType(object, t8, t8);
+    Check(eq, kOperandIsNotAFunction, t8, Operand(JS_FUNCTION_TYPE));
   }
 }
 
@@ -5391,11 +5384,9 @@ void MacroAssembler::AssertUndefinedOrAllocationSite(Register object,
     AssertNotSmi(object);
     LoadRoot(scratch, Heap::kUndefinedValueRootIndex);
     Branch(&done_checking, eq, object, Operand(scratch));
-    push(object);
-    ld(object, FieldMemOperand(object, HeapObject::kMapOffset));
+    ld(t8, FieldMemOperand(object, HeapObject::kMapOffset));
     LoadRoot(scratch, Heap::kAllocationSiteMapRootIndex);
-    Assert(eq, kExpectedUndefinedOrCell, object, Operand(scratch));
-    pop(object);
+    Assert(eq, kExpectedUndefinedOrCell, t8, Operand(scratch));
     bind(&done_checking);
   }
 }