[TableGen] Restore OpName::OPERAND_LAST emission in InstrInfoEmitter

[jurahul]

• Looks like this sentinel value is used in some downstream backends, so restore emitting it.
• It now also has the correct value (earlier code may have emitted an incorrect value for OPERAND_LAST and hence it was removed in [TableGen] Improvements to Named operands in InstrInfoEmitter #124960)

[llvmbot]

@llvm/pr-subscribers-tablegen

Author: Rahul Joshi (jurahul)

Changes

• Looks like this sentinel value is used in some downstream backends, so restore emitting it.
• It now also has the correct value (earlier code may have emitted an incorrect value for OPERAND_LAST and hence it was removed in [TableGen] Improvements to Named operands in InstrInfoEmitter #124960)

---

Full diff: https://github.com/llvm/llvm-project/pull/125265.diff

1 Files Affected:

• (modified) llvm/utils/TableGen/InstrInfoEmitter.cpp (+1)

diff --git a/llvm/utils/TableGen/InstrInfoEmitter.cpp b/llvm/utils/TableGen/InstrInfoEmitter.cpp
index 55e9d576b9b068..97c00ad4924197 100644
--- a/llvm/utils/TableGen/InstrInfoEmitter.cpp
+++ b/llvm/utils/TableGen/InstrInfoEmitter.cpp
@@ -286,6 +286,7 @@ void InstrInfoEmitter::emitOperandNameMappings(
   OS << "enum {\n";
   for (const auto &[I, Op] : enumerate(OperandNameToID))
     OS << "  " << Op.first << " = " << I << ",\n";
+  OS << "  OPERAND_LAST = " << NumOperandNames << ",\n";
   OS << "};\n";
   OS << "} // end namespace llvm::" << Namespace << "::OpName\n";
   OS << "#endif //GET_INSTRINFO_OPERAND_ENUM\n\n";

[topperc]

LGTM

[nvjle]

LGTM, thanks!

[llvm-ci]

LLVM Buildbot has detected a new failure on builder openmp-s390x-linux running on systemz-1 while building llvm at step 6 "test-openmp".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/88/builds/7489

Here is the relevant piece of the build log for the reference

Step 6 (test-openmp) failure: test (failure)
******************** TEST 'libomp :: tasking/issue-94260-2.c' FAILED ********************
Exit Code: -11

Command Output (stdout):
--
# RUN: at line 1
/home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/./bin/clang -fopenmp   -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test -L /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/src  -fno-omit-frame-pointer -mbackchain -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/ompt /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/tasking/issue-94260-2.c -o /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/tasking/Output/issue-94260-2.c.tmp -lm -latomic && /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/tasking/Output/issue-94260-2.c.tmp
# executed command: /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/./bin/clang -fopenmp -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test -L /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -fno-omit-frame-pointer -mbackchain -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/ompt /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/tasking/issue-94260-2.c -o /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/tasking/Output/issue-94260-2.c.tmp -lm -latomic
# executed command: /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/tasking/Output/issue-94260-2.c.tmp
# note: command had no output on stdout or stderr
# error: command failed with exit status: -11

--

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