[Polly][zorg] Enable GPGPU Codegen on the builders only if NVPTX is an LLVM target

[philip.pfaffe]

Summary

GPGPU Codegeneration requires the LLVM NVPTX target for it to work.
D47888 switches it off if that's not available, but still emits a warning.
Instead, just figure out if NVPTX is enabled and only then switch on GPGPU
codegen.

[Meinersbur]

zorg/buildbot/builders/PollyBuilder.py

78–79

[suggestion] any('LLVM_TARGETS_TO_BUILD' in A and 'NVPTX' in A for A in extraCmakeArgs)

Does this actually work? Isn't extraCmakeArgs formatted like ['-DLLVM_TARGETS_TO_BUILD=X86;NVPTX'], that is, neither 'LLVM_TARGETS_TO_BUILD' nor 'NVPTX' as entire strings are in the list.

80–81

Could you add a comment why this is here?

[philip.pfaffe]

zorg/buildbot/builders/PollyBuilder.py

78–79

Yes, that's why I'm iterating the list.

[philip.pfaffe]

Add a comment

[Meinersbur]

zorg/buildbot/builders/PollyBuilder.py

78–79

sorry, I seem to have confused 'NVPTX' in A and 'NVPTX' == A

[Meinersbur]

I still think that any(True for ... is unnecessary.

[philip.pfaffe]

In D47890#1125685, @Meinersbur wrote:

I still think that any(True for ... is unnecessary.

That's a way to find the first matching element and decide whether there is one in a compact functional way. Do you think it's stylistically questionable?

[Meinersbur]

In D47890#1126141, @philip.pfaffe wrote:

That's a way to find the first matching element and decide whether there is one in a compact functional way. Do you think it's stylistically questionable?

IMHO it is functionally identical to any('LLVM_TARGETS_TO_BUILD' in A and 'NVPTX' in A for A in extraCmakeArgs) which is even more compact. Why does your version add an if-constraint to the generator when any ignores false-ish elements anyway?

[philip.pfaffe]

Fix weird iterator comprehension.

[Meinersbur]

Sorry for the late reply

zorg/buildbot/builders/PollyBuilder.py

218

unrelated?

zorg/buildbot/builders/PollyBuilder.py

if clean:
                                workdir='.'))
 
     # Create configuration files with cmake
     f.addStep(ShellCommand(name="create-build-dir",
                            command=["mkdir", "-p", llvm_objdir],
                            haltOnFailure=False,
                            description=["create build dir"],
                            workdir="."))
+
     cmakeCommand = ["cmake", "../%s" %llvm_srcdir,
                     "-DCMAKE_COLOR_MAKEFILE=OFF",
                     "-DPOLLY_TEST_DISABLE_BAR=ON",
-                    "-DPOLLY_ENABLE_GPGPU_CODEGEN=ON",
                     "-DCMAKE_BUILD_TYPE=Release"] + cmake_install + extraCmakeArgs
+    hasNVPTX = any(True for A in reversed(extraCmakeArgs)
+                   if 'LLVM_TARGETS_TO_BUILD' in A and 'NVPTX' in A)
+    if hasNVPTX: # The NVPTX target is required to generate GPU code
+        cmakeCommand.append("-DPOLLY_ENABLE_GPGPU_CODEGEN=ON")
+
     f.addStep(ShellCommand(name="cmake-configure",
                            command=cmakeCommand,
                            haltOnFailure=False,
                            description=["cmake configure"],
                            workdir=llvm_objdir))
 
     # Build
     f.addStep(ShellCommand(name="build",
def getPollyLNTFactory(triple, nt_flags, xfails=[], clean=False, test=False,
     nt_flags.append('--cflag=' + '-Xclang')
     nt_flags.append(WithProperties("--cflag=%s/polly.install/lib/LLVMPolly.so",
                                    'builddir'))
 
     # Add an LNT test runner.
     LNTBuilder.AddLNTTestsToFactory(f, nt_flags,
                                     cc_path=(llvm_install_dir+'/bin/clang'),
                                     cxx_path=(llvm_install_dir+'/bin/clang++'),
                                     **lnt_args);
 
     return f