ARM/ARM64: Fix smashed CODE_REG in intrinsics with InvokeMathCFunctionInstrs.

runtime/vm/intrinsifier_x64.cc

Index: runtime/vm/intrinsifier_x64.cc
diff --git a/runtime/vm/intrinsifier_x64.cc b/runtime/vm/intrinsifier_x64.cc
index 58f096d3fdb95f1ed0b3250a61e6f3517936c496..d859c5ab2fcae20358804dd039e1509cc22eaa52 100644
--- a/runtime/vm/intrinsifier_x64.cc
+++ b/runtime/vm/intrinsifier_x64.cc
@@ -33,14 +33,22 @@ intptr_t Intrinsifier::ParameterSlotFromSp() { return 0; }
 
 
 void Intrinsifier::IntrinsicCallPrologue(Assembler* assembler) {
+  const intptr_t kAbiPreservedCpuRegs =
+      CallingConventions::kCalleeSaveCpuRegisters;
+  COMPILE_ASSERT((1 << CODE_REG) & kAbiPreservedCpuRegs);
+  COMPILE_ASSERT(((1 << ARGS_DESC_REG) & kAbiPreservedCpuRegs) == 0);
+  COMPILE_ASSERT((1 << CALLEE_SAVED_TEMP) & kAbiPreservedCpuRegs);
+  COMPILE_ASSERT(CALLEE_SAVED_TEMP != CODE_REG);
+  COMPILE_ASSERT(CALLEE_SAVED_TEMP != ARGS_DESC_REG);
+
   assembler->Comment("IntrinsicCallPrologue");
-  assembler->movq(CALLEE_SAVED_TEMP, R10);
+  assembler->movq(CALLEE_SAVED_TEMP, ARGS_DESC_REG);
 }
 
 
 void Intrinsifier::IntrinsicCallEpilogue(Assembler* assembler) {
   assembler->Comment("IntrinsicCallEpilogue");
-  assembler->movq(R10, CALLEE_SAVED_TEMP);
+  assembler->movq(ARGS_DESC_REG, CALLEE_SAVED_TEMP);
 }