This means that we get rid of tons of intermediate allocas. For
example:
void foo(double _Complex a, double _Complex b) {
a = b+a+a;
}
this used to have 4 temporary allocas, now it has zero of them.
This also simplifies the individual visitor methods because they
now can all operate on real/imag pairs instead of having to
load/store all over the place.
llvm-svn: 41217
