PNaCl: Add NoAlias attributes in ExpandByVal and ExpandVarArgs passes

test/Transforms/NaCl/expand-varargs.ll

 ; RUN: opt < %s -expand-varargs -S | FileCheck %s
 
 %va_list = type i8*
 
 declare void @llvm.va_start(i8*)
 declare void @llvm.va_end(i8*)
 declare void @llvm.va_copy(i8*, i8*)
 
 declare i32 @outside_func(i32 %arg, %va_list* %args)
 
 
 ; Produced by the expansion of @varargs_call1():
 ; CHECK: %vararg_call = type <{ i64, i32 }>
 
 ; Produced by the expansion of @call_with_zero_varargs().
 ; We have a dummy field to deal with buggy programs:
 ; CHECK: %vararg_call.0 = type <{ i32 }>
 
 
 define i32 @varargs_func(i32 %arg, ...) {
   %arglist_alloc = alloca %va_list
   %arglist = bitcast %va_list* %arglist_alloc to i8*
 
   call void @llvm.va_start(i8* %arglist)
   %result = call i32 @outside_func(i32 %arg, %va_list* %arglist_alloc)
   call void @llvm.va_end(i8* %arglist)
   ret i32 %result
 }
-; CHECK: define i32 @varargs_func(i32 %arg, i8* %varargs) {
+; CHECK: define i32 @varargs_func(i32 %arg, i8* noalias %varargs) {
 ; CHECK-NEXT: %arglist_alloc = alloca i8*
 ; CHECK-NEXT: %arglist = bitcast i8** %arglist_alloc to i8*
 ; CHECK-NEXT: %arglist1 = bitcast i8* %arglist to i8**
 ; CHECK-NEXT: store i8* %varargs, i8** %arglist1
 ; CHECK-NEXT: %result = call i32 @outside_func(i32 %arg, i8** %arglist_alloc)
 ; CHECK-NEXT: ret i32 %result
 
 
 define i32 @varargs_call1() {
   %result = call i32 (i32, ...)* @varargs_func(i32 111, i64 222, i32 333)
@@ skipping 85 matching lines @@
 define void @do_va_copy(i8* %dest, i8* %src) {
   call void @llvm.va_copy(i8* %dest, i8* %src)
   ret void
 }
 ; CHECK: define void @do_va_copy(i8* %dest, i8* %src) {
 ; CHECK-NEXT: %vacopy_src = bitcast i8* %src to i8**
 ; CHECK-NEXT: %vacopy_dest = bitcast i8* %dest to i8**
 ; CHECK-NEXT: %vacopy_currentptr = load i8** %vacopy_src
 ; CHECK-NEXT: store i8* %vacopy_currentptr, i8** %vacopy_dest
 ; CHECK-NEXT: ret void