[DebugInfo][RemoveDIs] Remove some debug intrinsic-only codepaths (#143451)

These are opportunistic deletions as more places that make use of the
IsNewDbgInfoFormat flag are removed. It should (TM)(R) all be dead code
now that `IsNewDbgInfoFormat` should be true everywhere.

FastISel: we don't need to do debug-aware instruction counting any more,
because there are no debug instructions,
Autoupgrade: you can no-longer avoid autoupgrading of intrinsics to
records
DIBuilder: Delete the code for creating debug intrinsics (!)
LoopUtils: No need to handle debug instructions, they don't exist

1 files changed, 11 insertions, 25 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp
index 0681ebc..ff69fa9 100644
--- a/llvm/lib/Transforms/Utils/LoopUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUtils.cpp
@@ -606,7 +606,6 @@ void llvm::deleteDeadLoop(Loop *L, DominatorTree *DT, ScalarEvolution *SE,
 
   // Use a map to unique and a vector to guarantee deterministic ordering.
   llvm::SmallDenseSet<DebugVariable, 4> DeadDebugSet;
-  llvm::SmallVector<DbgVariableIntrinsic *, 4> DeadDebugInst;
   llvm::SmallVector<DbgVariableRecord *, 4> DeadDbgVariableRecords;
 
   if (ExitBlock) {
@@ -633,29 +632,19 @@ void llvm::deleteDeadLoop(Loop *L, DominatorTree *DT, ScalarEvolution *SE,
           U.set(Poison);
         }
 
-        // RemoveDIs: do the same as below for DbgVariableRecords.
-        if (Block->IsNewDbgInfoFormat) {
-          for (DbgVariableRecord &DVR : llvm::make_early_inc_range(
-                   filterDbgVars(I.getDbgRecordRange()))) {
-            DebugVariable Key(DVR.getVariable(), DVR.getExpression(),
-                              DVR.getDebugLoc().get());
-            if (!DeadDebugSet.insert(Key).second)
-              continue;
-            // Unlinks the DVR from it's container, for later insertion.
-            DVR.removeFromParent();
-            DeadDbgVariableRecords.push_back(&DVR);
-          }
-        }
-
-        // For one of each variable encountered, preserve a debug intrinsic (set
+        // For one of each variable encountered, preserve a debug record (set
         // to Poison) and transfer it to the loop exit. This terminates any
         // variable locations that were set during the loop.
-        auto *DVI = dyn_cast<DbgVariableIntrinsic>(&I);
-        if (!DVI)
-          continue;
-        if (!DeadDebugSet.insert(DebugVariable(DVI)).second)
-          continue;
-        DeadDebugInst.push_back(DVI);
+        for (DbgVariableRecord &DVR :
+             llvm::make_early_inc_range(filterDbgVars(I.getDbgRecordRange()))) {
+          DebugVariable Key(DVR.getVariable(), DVR.getExpression(),
+                            DVR.getDebugLoc().get());
+          if (!DeadDebugSet.insert(Key).second)
+            continue;
+          // Unlinks the DVR from it's container, for later insertion.
+          DVR.removeFromParent();
+          DeadDbgVariableRecords.push_back(&DVR);
+        }
       }
 
     // After the loop has been deleted all the values defined and modified
@@ -671,9 +660,6 @@ void llvm::deleteDeadLoop(Loop *L, DominatorTree *DT, ScalarEvolution *SE,
            "There should be a non-PHI instruction in exit block, else these "
            "instructions will have no parent.");
 
-    for (auto *DVI : DeadDebugInst)
-      DVI->moveBefore(*ExitBlock, InsertDbgValueBefore);
-
     // Due to the "head" bit in BasicBlock::iterator, we're going to insert
     // each DbgVariableRecord right at the start of the block, wheras dbg.values
     // would be repeatedly inserted before the first instruction. To replicate