port:libclang (and libLLVM)

Jack Howarth howarth.at.macports at gmail.com
Thu Mar 10 07:13:16 PST 2016

On Thu, Mar 10, 2016 at 7:33 AM, René J.V. <rjvbertin at gmail.com> wrote:
> On Wednesday March 09 2016 20:48:19 Jack Howarth wrote:
>>> Why? My understanding is that the optimizations for -Os are equivalent
>>> to -O2 with the emphasis on size reduction. The additional
>>> optimizations from -O2 to -O3 would seem sufficient to produce a 10%
>>> execution optimization, no?
> Actually, this point is moot : -Os is used only on PPC machines from what I can see. Other architectures use whatever optimisation the build system decides to use (which is an interesting question when that system is based on CMake and you use one of the built-in BUILD_TYPE presets).

A simple test with 'sudo port -d -s build llvm-3.8' reveals that -Os
is in fact used during the compiles on Intel. This is unsurprising as
MacPorts has standardized on -Os.

CFLAGS='-pipe -Os'
CXXFLAGS='-pipe -Os -std=c++11 -stdlib=libc++'
F90FLAGS='-pipe -Os -m64'
FCFLAGS='-pipe -Os -m64'
FFLAGS='-pipe -Os'
OBJCFLAGS='-pipe -Os'
OBJCXXFLAGS='-pipe -Os -stdlib=libc++'

> R.

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