[PowerPC] Fix the check for scalar MASS conversion

[masoud.ataei]

Summary

Proposing to move the check for scalar MASS conversion from constructor
of PPCTargetLowering to the lowerLibCallBase function which decides
about the lowering.

The Target machine option Options.PPCGenScalarMASSEntries is set in
PPCTargetMachine.cpp. But an object of the class PPCTargetLowering
is created in one of the included header files. So, the constructor will run
before setting PPCGenScalarMASSEntries to correct value. So, we cannot
check this option in the constructor.

[bmahjour]

The description should explain why this change is necessary.

clang/test/CodeGen/lower-mass-end-to-end.c

2

Please add negative end-to-end tests as well (eg. when -enable-ppc-gen-scalar-mass is false or when -fno-approx-func).

[masoud.ataei]

Add more tests.

[bmahjour]

clang/test/CodeGen/lower-mass-end-to-end.c

34–35

Please also check for

CHECK-NOMASS-FAST-NOT: xl_sin
CHECK-NOMASS-AFN-NOT: xl_sin_finit

and do the same for other tests.

[masoud.ataei]

Test updated.

[bmahjour]

clang/test/CodeGen/lower-mass-end-to-end.c

34

I don't think this works the way you expect it:

> cat input.txt
; CHECK-NOT: __xl_sin{{_finite}}
> echo "__xl_sin" | ./bin/FileCheck ./input.txt
>

this seems closer to what you want:

; CHECK-NOT: {{__xl_sin|__xl_sin_finite}}

[masoud.ataei]

Update the test

[bmahjour]

LGTM. Thanks!

[dyung]

Hi @masoud.ataei, the test you added in this commit is failing on the PS4 bot, can you take a look?

https://lab.llvm.org/buildbot/#/builders/139/builds/24469

clang (LLVM option parsing): Unknown command line argument '-enable-ppc-gen-scalar-mass'.  Try: 'clang (LLVM option parsing) --help'
clang (LLVM option parsing): Did you mean '--enable-x86-scalar-amx'?

[masoud.ataei]

Just took it down temporarily. -- Looking at it...

[lenary]

You likely need // REQUIRES: powerpc-registered-target in the top of the test, as -enable-ppc-gen-scalar-mass is only present if the PowerPC target has been compiled into LLVM.

[masoud.ataei]

In D128653#3633704, @lenary wrote:

You likely need // REQUIRES: powerpc-registered-target in the top of the test, as -enable-ppc-gen-scalar-mass is only present if the PowerPC target has been compiled into LLVM.

Thanks, I was looking for that. -- re-committing...