Extended Description

When emitting code for a new array expression we check whether the array size is negative in C++98 and C++11 mode, but not from C++14 onwards. E.g.

char *foo(int a) {
return new char[a];
}

$ clang++ tmp.cpp -std=c++11 -S -o- -emit-llvm -Os
define noalias nonnull i8* @​_Z3fooi(i32 %a) local_unnamed_addr #​0 {
entry:
%0 = sext i32 %a to i64
%1 = icmp sgt i64 %0, -1
%2 = select i1 %1, i64 %0, i64 -1
%call = tail call i8* @​_Znam(i64 %2) #​2
ret i8* %call
}

$ clang++ tmp.cpp -std=c++14 -S -o- -emit-llvm -Os
define noalias nonnull i8* @​_Z3fooi(i32 %a) local_unnamed_addr #​0 {
entry:
%conv = sext i32 %a to i64
%call = tail call i8* @​_Znam(i64 %conv) #​2
ret i8* %call
}