Hi @MaskRay, could you please take a look at @nemanjai's suggestion?

...
So I would prefer that we handle this in the CMake files if @MaskRay doesn't object.

Adding lit config to mark tests as unsupported for non PPC targets.

Addressing review comments: fixing test cases and improving test case clarity.

Adressing review comments. Moving tests into function-sections.c, using %s instead of creating a new file with touch, and modifying some CHECK lines to simplify checks.

Adressed review comments.

• Modified how llvm-lto test-cases check the llvm-objdump -t output.
• Renamed gold-lto-sections.c to forwarding-sections-liblto.c and modified the test to use the RUN lines from forwarding-sections-liblto.c with the target specified using --target=.

In D129401#3666238, @MaskRay wrote:

Mostly looks good, with a nit in the test and some suggestion to the summary.

In D129401#3662857, @quinnp wrote:

If this is for the legacy LTO interface, please state so. lld/*/LTO.cpp sets c.Options.DataSections = true; to enable data sections by default.

Hey @MaskRay, I'm not sure what is considered the legacy LTO interface, but this change is to make the libLTO codegen match the behaviour of LTO used through lld and gold plugin. Both lld and gold plugin turn on data-sections for LTO by default:

• as you mentioned lld/*/LTO.cpp sets c.Options.DataSections = true; by default.
• and llvm/tools/gold/gold-plugin.cpp sets Conf.Options.DataSections = SplitSections; provided that the user did not explicitly set/unset data-sections where SplitSections is true unless gold plugin is doing a relocatable link.

There is a legacy LTO interface (see llvm/include/llvm/LTO/legacy/LTOCodeGenerator.h) and a resolution-based interface.
Change libLTO in "This patch changes libLTO to set data-sections by default." to legacy LTO.

This patch also fixes the forwarding of the clang options -fno-data-sections and -fno-function-sections to libLTO

This sentence can keep using libLTO or LLVMLTO (the library is LLVMLTO per llvm/lib/LTO/CMakeLists.txt)

Addressing review comments. Changing test cases to use llvm-objdump -t instead of obj2yaml.

Addressing review comments. Fixing the forwarding for -fno-function-sectons and removing the ObjectFormatType check.

Modifying a test to fix check lines.

If this is for the legacy LTO interface, please state so. lld/*/LTO.cpp sets c.Options.DataSections = true; to enable data sections by default.

Fixing test case.

In D129855#3657006, @MaskRay wrote:

This is not right as using ld.lld as the default linker isn't the majority case. If you want to change the default for your distribution, set -DCLANG_DEFAULT_LINKER=lld.
(Alternatively, you can have a ld symlink pointing to lld.)

Addressing review comment.

Updating patch to forward -data-sections=1 to libLTO/gold instead of just -data-sections when -fdata-sections is explicitly specified in clang. This is to be more explicit since -data-sections=0 is now being forwared when -fno-data-sections is explicitly specified.

Updating patch with a clang change to properly forward -data-sections=0 to libLTO/gold when -fno-data-sections is explicitly specified.

In D129401#3660001, @w2yehia wrote:

In D129401#3655316, @quinnp wrote:

I've realized that getExplicitDataSections() interacts with ...

Yes, that seems to be the case that clang forwards the -data-sections option to libLTO/gold only when it's ON. It might be that at that time teh default was assumed to be OFF in libLTO/gold.
Users can still disable it by passing the option manually (i.e. -plugin-opt=-data-sections=0).
The forwarding logic in clang shud be fixed at some point.

I've realized that getExplicitDataSections() interacts with the clang options -fdata-sections and -fno-data-sections differently than the llc versions of these options, --data-sections=true and --data-sections=false. In particular,

• when --data-sections=true is specified with llvm-lto, getExplicitDataSections() returns 1
• when --data-sections=false is specified with llvm-lto, getExplicitDataSections() returns 0
• when no data-sections options are specified with llvm-lto, getExplicitDataSections() returns None.
• when -fdata-sections is specified with clang, getExplicitDataSections() returns 1
• when -fno-data-sections is specified with clang, getExplicitDataSections() returns None.
• when no data-sections options are specified with clang, getExplicitDataSections() returns None.

LGTM. Thanks!

Adding a comments to the early exits in expandVSXLoadForLE and expandVSXStoreForLE.

Updating patch to delay SVX load and store combine until after legalization.

LGTM as well aside from Zarko's comment.

Rebasing with main.

I did not remove that on purpose, so adding it back makes sense to me.

I've updated the patch to remove the path without the /root/usr suffix and exclusively add the path with the root/usr suffix.

Addressing review comments. Removing path without /root/usr suffix and changing unit test to match.

Hi, this patch broke one of the PowerPC bots (https://lab.llvm.org/buildbot/#/builders/121). unix03-sigpipe-exit.test is failing. Here is the first build with this patch: https://lab.llvm.org/buildbot/#/builders/121/builds/20219

Thank you @nemanjai! I've updated the patch based on your suggestion and tested it for both the existing testcase and the RHEL buildbot failure.

Addressing review comments.

Other than my comment, LGTM

Fixing failing tests added in this patch.

Small change for consistency.

Small change for consistency. llvm::Value -> Value

Updating patch with a fix for emitting builtin arguments in an unspecified order.

Re-opening the revision so that I can update it with a fix.

In D121637#3437371, @thakis wrote:

Looks like this breaks tests on windows: http://45.33.8.238/win/55893/step_7.txt

Please take a look and revert for now if it takes a while to fix.

Fixing a set of builtins added by the rebase with main.

Rebasing with main.

Fixing some testcases that broke due to re-ordering IR in my last update.

Adressing review comments. Added a testcase which fails prior to this patch due to the arguments being emmited multiple times. Refactored some calls to EmitScalarExpr() to be more consistent.

Moving testcases that require code generation from clang/test/Sema/ppc-pair-mma-types.c to clang/test/CodeGen/PowerPC/ppc-mma-types.c and clang/test/CodeGen/PowerPC/builtins-ppc-pair-mma-types.c. This is because some of these tests use the line Ops.push_back(EmitArrayToPointerDecay(E->getArg(i)).getPointer()); which I initially removed from EmitPPCbuiltinExpr. I have added this back in the switch statement where it is needed.

LGTM

Fixing a failing test case.