We had been prohibiting Windows users from providing #definitions on the command
line, which is the wrong thing to do ever since we switched to using the
clang preprocessor.
If no CPU is specified, use the host CPU type, not just a default of "nehalem".
Provide better features strings to the LLVM target machinery.
-> Thus ensuring that LLVM doesn't generate SSE>2 instructions for the SSE2
target (Fixes issue #82).
-> Slight code improvements from using cmovs in generated code now
Use the llvm popcnt intrinsic for the SSE2 target now (it now generates code
that doesn't call the popcnt instruction now that we properly tell LLVM
which instructions are and aren't available for SSE2.)
Set the Module's target appropriately when it's first created.
Compile separate 32 and 64 bit versions of the builtins-c bitcocde
and load the appropriate one based on the target we're compiling
for.
Add optimization patterns to detect and simplify masked loads and stores
with the mask all on / all off.
Enable AVX for LLVM 3.0 builds (still generally hits bugs / unimplemented
stuff on the LLVM side, but it's getting there).
