[llvm-reduce][DebugInfo] Support reducing non-instruction debug-info (#78995)

LLVM will shortly be able to represent variable locations without
encoding information into intrinsics -- they'll be stored as DPValue
objects instead. We'll still need to be able to llvm-reduce these
variable location assignments just like we can with intrinsics today,
thus, here's an llvm-reduce pass that enumerates and reduces the DPValue
objects.

The test for this is paradoxically written with dbg.value intrinsics:
this is because we're changing all the core parts of LLVM to support
this first, with the textual IR format coming last. Until that arrives,
testing the llvm-reduce'ing of DPValues needs the added test using
intrinsics. We should be able to drop the variable assignment using
%alsoloaded using this method. As with the other llvm-reduce tests, I've
got one set of check lines for making the reduction happen as desired,
and the other set to check the final output.

1 files changed, 18 insertions, 0 deletions

diff --git a/llvm/tools/llvm-reduce/llvm-reduce.cpp b/llvm/tools/llvm-reduce/llvm-reduce.cpp
index bd2db63..71ce0ca5 100644
--- a/llvm/tools/llvm-reduce/llvm-reduce.cpp
+++ b/llvm/tools/llvm-reduce/llvm-reduce.cpp
@@ -100,6 +100,13 @@ static cl::opt<int>
                                "of delta passes (default=5)"),
                       cl::init(5), cl::cat(LLVMReduceOptions));
 
+static cl::opt<bool> TryUseNewDbgInfoFormat(
+    "try-experimental-debuginfo-iterators",
+    cl::desc("Enable debuginfo iterator positions, if they're built in"),
+    cl::init(false));
+
+extern cl::opt<bool> UseNewDbgInfoFormat;
+
 static codegen::RegisterCodeGenFlags CGF;
 
 /// Turn off crash debugging features
@@ -143,6 +150,17 @@ int main(int Argc, char **Argv) {
   cl::HideUnrelatedOptions({&LLVMReduceOptions, &getColorCategory()});
   cl::ParseCommandLineOptions(Argc, Argv, "LLVM automatic testcase reducer.\n");
 
+  // RemoveDIs debug-info transition: tests may request that we /try/ to use the
+  // new debug-info format, if it's built in.
+#ifdef EXPERIMENTAL_DEBUGINFO_ITERATORS
+  if (TryUseNewDbgInfoFormat) {
+    // If LLVM was built with support for this, turn the new debug-info format
+    // on.
+    UseNewDbgInfoFormat = true;
+  }
+#endif
+  (void)TryUseNewDbgInfoFormat;
+
   if (Argc == 1) {
     cl::PrintHelpMessage();
     return 0;