llvm-reduce: Reduce individual operands of named metadata

[arsenm]

Summary

The current reduction tries all or nothing elimination of named
metadata. I noticed in one case where one of the module flags was
necessary, but it left the rest. Reduce the individual operands of
named metadata nodes that are known to behave like lists. Be
conservative since some named metadata may have more specific verifier
requirements for the operands.

[dexonsmith]

LGTM with one bit inline.

llvm/tools/llvm-reduce/deltas/ReduceMetadata.cpp

57

Seems like it’d be nice to precede this with a check that anything has changed (if nothing has changed, continue…)

[arsenm]

5f6bf752d9a7efaf6533d6ad375ab0231eef8012

llvm/test/tools/llvm-reduce/reduce-module-flags.ll

+; Test keeping one module flag
+; RUN: llvm-reduce --abort-on-invalid-reduction --delta-passes=named-metadata --test=FileCheck --test-arg=--check-prefix=CHECK-INTERESTINGNESS0 --test-arg=%s --test-arg=--input-file %s -o %t.0
+; RUN: FileCheck --check-prefix=RESULT0 %s < %t.0
+
+; Test keeping two module flags
+; RUN: llvm-reduce --abort-on-invalid-reduction --delta-passes=named-metadata --test=FileCheck --test-arg=--check-prefix=CHECK-INTERESTINGNESS1 --test-arg=%s --test-arg=--input-file %s -o %t.1
+; RUN: FileCheck --check-prefix=RESULT1 %s < %t.1
+
+
+; Test removing all module flags
+; RUN: llvm-reduce --abort-on-invalid-reduction --delta-passes=named-metadata --test=FileCheck --test-arg=--check-prefix=CHECK-INTERESTINGNESS2 --test-arg=%s --test-arg=--input-file %s -o %t.2
+; RUN: FileCheck --check-prefix=RESULT2 %s < %t.2
+
+
+; CHECK-INTERESTINGNESS0: "openmp-device"
+
+; CHECK-INTERESTINGNESS1: "wchar_size"
+; CHECK-INTERESTINGNESS1: "openmp"
+
+; CHECK-INTERESTINGNESS2: !llvm.module.flags
+
+; RESULT0: !llvm.module.flags = !{!0}
+; RESULT0: !0 = !{i32 7, !"openmp-device", i32 50}
+
+
+; RESULT1: !llvm.module.flags = !{!0, !1}
+; RESULT1: !0 = !{i32 1, !"wchar_size", i32 4}
+; RESULT1: !1 = !{i32 7, !"openmp", i32 50}
+
+
+; RESULT2: !llvm.module.flags = !{}
+
+!llvm.module.flags = !{!0, !1, !2, !3, !4, !5}
+
+!0 = !{i32 1, !"amdgpu_code_object_version", i32 400}
+!1 = !{i32 1, !"wchar_size", i32 4}
+!2 = !{i32 7, !"openmp", i32 50}
+!3 = !{i32 7, !"openmp-device", i32 50}
+!4 = !{i32 8, !"PIC Level", i32 1}
+!5 = !{i32 1, !"LTOPostLink", i32 1}

llvm/test/tools/llvm-reduce/reduce-named-metadata.ll

+; RUN: llvm-reduce --abort-on-invalid-reduction --delta-passes=named-metadata --test=FileCheck --test-arg=--check-prefix=CHECK-INTERESTINGNESS --test-arg=%s --test-arg=--input-file %s -o %t
+; RUN: FileCheck --check-prefix=RESULT %s < %t
+; Test the various named metadata recognized for simple list behavior.
+
+; CHECK-INTERESTINGNESS: !llvm.ident = !{![[LLVM_IDENT:[0-9]+]]
+; CHECK-INTERESTINGNESS: !opencl.spir.version = !{{{.*}}![[SPIR_VERSION:[0-9]+]]}
+; CHECK-INTERESTINGNESS: !opencl.ocl.version = !{{{.*}}![[OCL_VERSION:[0-9]+]]}
+; CHECK-INTERESTINGNESS: !opencl.used.extensions = !{{{.*}}![[OCL_EXTENSION:[0-9]+]]}
+; CHECK-INTERESTINGNESS: !opencl.used.optional.core.features = !{{{.*}}![[OCL_OPTIONAL_CORE_FEATURE:[0-9]+]]}
+; CHECK-INTERESTINGNESS: !opencl.compiler.options = !{{{.*}}![[OCL_COMPILER_OPTIONS:[0-9]+]]}
+
+; CHECK-DAG: CHECK-INTERESTINGNESS: ![[LLVM_IDENT]] = !{!"some llvm version 0"}
+; CHECK-DAG: CHECK-INTERESTINGNESS: ![[SPIR_VERSION]] = !{!"some spir version 1"}
+; CHECK-DAG: CHECK-INTERESTINGNESS: ![[OCL_VERSION]] = !{!"some ocl version 1"}
+; CHECK-DAG: CHECK-INTERESTINGNESS: ![[OCL_EXTENSION]] = !{!"some ocl extension 1"}
+; CHECK-DAG: CHECK-INTERESTINGNESS: ![[OCL_OPTIONAL_CORE_FEATURE]] = !{!"some ocl optional core feature 1"}
+; CHECK-DAG: CHECK-INTERESTINGNESS: ![[OCL_COMPILER_OPTIONS]] = !{!"some ocl compiler option 1"}
+
+
+; RESULT: !llvm.ident = !{![[LLVM_IDENT:[0-9]+]]
+; RESULT: !opencl.spir.version = !{![[SPIR_VERSION:[0-9]+]]}
+; RESULT: !opencl.ocl.version = !{![[OCL_VERSION:[0-9]+]]}
+; RESULT: !opencl.used.extensions = !{![[OCL_EXTENSION:[0-9]+]]}
+; RESULT: !opencl.used.optional.core.features = !{![[OCL_OPTIONAL_CORE_FEATURE:[0-9]+]]}
+; RESULT: !opencl.compiler.options = !{![[OCL_COMPILER_OPTION:[0-9]+]]}
+; RESULT: !some.unknown.named = !{![[UNKNOWN_0:[0-9]+]], ![[UNKNOWN_1:[0-9]+]]}
+
+
+; RESULT: ![[LLVM_IDENT]] = !{!"some llvm version 0"}
+; RESULT: ![[SPIR_VERSION]] = !{!"some spir version 1"}
+; RESULT: ![[OCL_VERSION]] = !{!"some ocl version 1"}
+; RESULT: ![[OCL_EXTENSION]] = !{!"some ocl extension 1"}
+; RESULT: ![[OCL_OPTIONAL_CORE_FEATURE]] = !{!"some ocl optional core feature 1"}
+; RESULT: ![[OCL_COMPILER_OPTION]] = !{!"some ocl compiler option 1"}
+; RESULT: ![[UNKNOWN_0]] = !{!"some unknown option 0"}
+; RESULT: ![[UNKNOWN_1]] = !{!"some unknown option 1"}
+
+!llvm.ident = !{!0, !1, !0}
+!opencl.spir.version = !{!2, !3}
+!opencl.ocl.version = !{!4, !5}
+!opencl.used.extensions = !{!6, !7}
+!opencl.used.optional.core.features = !{!8, !9}
+!opencl.compiler.options = !{!10, !11}
+!some.unknown.named = !{!12, !13}
+
+!0 = !{!"some llvm version 0"}
+!1 = !{!"some llvm version 1"}
+!2 = !{!"some spir version 0"}
+!3 = !{!"some spir version 1"}
+!4 = !{!"some ocl version 0"}
+!5 = !{!"some ocl version 1"}
+!6 = !{!"some ocl extension 0"}
+!7 = !{!"some ocl extension 1"}
+!8 = !{!"some ocl optional core feature 0"}
+!9 = !{!"some ocl optional core feature 1"}
+!10 = !{!"some ocl compiler option 0"}
+!11 = !{!"some ocl compiler option 1"}
+!12 = !{!"some unknown option 0"}
+!13 = !{!"some unknown option 1"}

llvm/tools/llvm-reduce/DeltaManager.cpp

do {                                                                         \
     DELTA_PASS("basic-blocks", reduceBasicBlocksDeltaPass)                     \
     DELTA_PASS("simplify-cfg", reduceUsingSimplifyCFGDeltaPass)                \
     DELTA_PASS("global-values", reduceGlobalValuesDeltaPass)                   \
     DELTA_PASS("global-objects", reduceGlobalObjectsDeltaPass)                 \
     DELTA_PASS("global-initializers", reduceGlobalsInitializersDeltaPass)      \
     DELTA_PASS("global-variables", reduceGlobalsDeltaPass)                     \
     DELTA_PASS("di-metadata", reduceDIMetadataDeltaPass)                       \
     DELTA_PASS("metadata", reduceMetadataDeltaPass)                            \
+    DELTA_PASS("named-metadata", reduceNamedMetadataDeltaPass)                 \
     DELTA_PASS("arguments", reduceArgumentsDeltaPass)                          \
     DELTA_PASS("instructions", reduceInstructionsDeltaPass)                    \
     DELTA_PASS("simplify-instructions", simplifyInstructionsDeltaPass)         \
     DELTA_PASS("ir-passes", runIRPassesDeltaPass)                              \
     DELTA_PASS("operands-zero", reduceOperandsZeroDeltaPass)                   \
     DELTA_PASS("operands-one", reduceOperandsOneDeltaPass)                     \
     DELTA_PASS("operands-nan", reduceOperandsNaNDeltaPass)                     \
     DELTA_PASS("operands-to-args", reduceOperandsToArgsDeltaPass)              \

llvm/tools/llvm-reduce/deltas/ReduceMetadata.h

 
 #ifndef LLVM_TOOLS_LLVM_REDUCE_DELTAS_REDUCEMETADATA_H
 #define LLVM_TOOLS_LLVM_REDUCE_DELTAS_REDUCEMETADATA_H
 
 #include "TestRunner.h"
 
 namespace llvm {
 void reduceMetadataDeltaPass(TestRunner &Test);
+void reduceNamedMetadataDeltaPass(TestRunner &Test);
 } // namespace llvm
 
 #endif

llvm/tools/llvm-reduce/deltas/ReduceMetadata.cpp

 static bool shouldKeepDebugIntrinsicMetadata(Instruction &I, MDNode &MD) {
   return isa<DILocation>(MD) && isa<DbgInfoIntrinsic>(I);
 }
 
 static bool shouldKeepDebugNamedMetadata(NamedMDNode &MD) {
   return MD.getName() == "llvm.dbg.cu" && MD.getNumOperands() != 0;
 }
 
+// Named metadata with simple list-like behavior, so that it's valid to remove
+// operands individually.
+static constexpr StringLiteral ListNamedMetadata[] = {
+  "llvm.module.flags",
+  "llvm.ident",
+  "opencl.spir.version",
+  "opencl.ocl.version",
+  "opencl.used.extensions",
+  "opencl.used.optional.core.features",
+  "opencl.compiler.options"
+};
+
+/// Remove unneeded arguments to named metadata.
+static void reduceNamedMetadataOperands(Oracle &O, Module &M) {
+  for (StringRef MDName : ListNamedMetadata) {
+    NamedMDNode *NamedNode = M.getNamedMetadata(MDName);
+    if (!NamedNode)
+      continue;
+
+    SmallVector<MDNode *, 16> KeptOperands;
+    for (auto I : seq<unsigned>(0, NamedNode->getNumOperands())) {
+      if (O.shouldKeep())
+        KeptOperands.push_back(NamedNode->getOperand(I));
+    }
+
+    NamedNode->clearOperands();
+    for (MDNode *KeptOperand : KeptOperands)
+      NamedNode->addOperand(KeptOperand);
+  }
+}
+
 /// Removes all the Named and Unnamed Metadata Nodes, as well as any debug
 /// functions that aren't inside the desired Chunks.
 static void extractMetadataFromModule(Oracle &O, Module &Program) {
   // Get out-of-chunk Named metadata nodes
   SmallVector<NamedMDNode *> NamedNodesToDelete;
   for (NamedMDNode &MD : Program.named_metadata())
     if (!shouldKeepDebugNamedMetadata(MD) && !O.shouldKeep())
       NamedNodesToDelete.push_back(&MD);
for (Instruction &I : instructions(F)) {
       }
     }
   }
 }
 
 void llvm::reduceMetadataDeltaPass(TestRunner &Test) {
   runDeltaPass(Test, extractMetadataFromModule, "Reducing Metadata");
 }
+
+void llvm::reduceNamedMetadataDeltaPass(TestRunner &Test) {
+  runDeltaPass(Test, reduceNamedMetadataOperands, "Reducing Named Metadata");
+}