Implement or.ll:test21.  This teaches instcombine to be able to turn this:

struct {
   unsigned int bit0:1;
   unsigned int ubyte:31;
} sdata;

void foo() {
  sdata.ubyte++;
}

into this:

foo:
        add DWORD PTR [sdata], 2
        ret

instead of this:

foo:
        mov %EAX, DWORD PTR [sdata]
        mov %ECX, %EAX
        add %ECX, 2
        and %ECX, -2
        and %EAX, 1
        or %EAX, %ECX
        mov DWORD PTR [sdata], %EAX
        ret

llvm-svn: 23376
1 file changed
tree: 94fb568586bb7752350a660a32e1fd40c4ae2ce6
  1. llvm/