[PATCH] D21006: [Driver] Make -flto -S emit assembly

[Davide Italiano via cfe-commits]

davide added a comment.

In http://reviews.llvm.org/D21006#449409, @dexonsmith wrote:

> I agree with Mehdi.  I expect `-S -flto` to give equivalent output to `-c -flto`.
>
> In effect, with this change, `-flto -S` would silently ignore the `-flto` flag.  That doesn't make sense to me.


I guess there's enough disagreement to hold on on this change.
My $0.02: When I ask for -S I really expect asm to be produced, but maybe it's just me =)
Lots of build systems have invocations of clang like:

  CFLAGS= -S
  ${CC} ${CFLAGS} blah.c -o blah.s
  sed -e ...

When CFLAGS is changed, as in:

  CFLAGS += -flto

this is generally passed globally. So, not emitting ASM in this case makes LTO non transparent for the build system, i.e. Makefiles need to pass `-fno-lto`, which might not be terrible overall, just not what I expect.


http://reviews.llvm.org/D21006