Commited extra float C99 functions in rGf4a369596f7b.

After the nsz check is addressed, it LGTM.

In D57434#1377569, @Whitney wrote:

@evandro Why do we want to add new cases in test/Transforms/InstCombine/pow-sqrt.ll? Am I right that InstCombine tests opt? This new changes happen in llc.

Separated functions between VC19 and float.

Assume VC19 as the default. However, I wonder if this should be the default earlier, in the clang driver.

Restrict the improvements to VS2015.

In D57625#1386061, @rnk wrote:

Do we know when most of these were added? Did the all arrive in more or less the same version? It would be nice to make this conditional on a new enough environment version. That gives users a way to indicate that they are targetting an old CRT if they need to.

Rebase.

Include ARM.

In D57625#1384950, @mstorsjo wrote:

But the other point still stands; even if compiling LLVM requires VS 2015 or newer, the generated code can work with older MSVC runtimes as well. @rnk - is there any declared minimum for this? I'm using Clang with MSVC 2013 SDK/runtimes just fine in one setup at least (although this setup currently uses Clang/LLVM 4.0, I haven't recently retested it with latest). AFAIK, the exact version of MSVC that is targeted is kept available via Triplet::getEnvironmentVersion, so unless it's intended to drop support for all the older runtimes as well, this would have to check the version of it.

In D57625#1382005, @mstorsjo wrote:

(And it also works with mingw which normally uses an ancient msvcrt.)

Please, add a test for AArch64 and new cases in test/Transforms/InstCombine/pow-sqrt.ll as well.

Replaced the test case with a MIR file.

I'm afraid that I'll need more time to craft the MIR file. Then, I might as well do the same for the other fusion tests.

In D56572#1354333, @fhahn wrote:

Would it be possible to have a MIR test here, which just runs the scheduler?

Sorry, I was juggling too many patches out of order.

Note that I made this patch a predecessor for D55345.

Rebase the patch.