[PATCH] D77639: [DebugInfo][NFC] Early-exit when analysing for single-location variables

[Jeremy Morse via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rGc77887e4d1be: [DebugInfo][NFC] Early-exit when analyzing for single-location variables (authored by jmorse).

Changed prior to commit:
  https://reviews.llvm.org/D77639?vs=255637&id=255963#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D77639/new/

https://reviews.llvm.org/D77639

Files:
  llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp


Index: llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
===================================================================
--- llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1480,11 +1480,24 @@
   if (LSRange.size() == 0)
     return false;
 
+  // If this range is neither open ended nor a constant, then it is not a
+  // candidate for being validThroughout.
+  if (RangeEnd && !DbgValue->getOperand(0).isImm())
+    return false;
+
   // Determine if the DBG_VALUE is valid at the beginning of its lexical block.
   const MachineInstr *LScopeBegin = LSRange.front().first;
   // Early exit if the lexical scope begins outside of the current block.
   if (LScopeBegin->getParent() != MBB)
     return false;
+
+  // If there are instructions belonging to our scope in another block, and
+  // we're not a constant (see DWARF2 comment below), then we can't be
+  // validThroughout.
+  const MachineInstr *LScopeEnd = LSRange.back().second;
+  if (RangeEnd && LScopeEnd->getParent() != MBB)
+    return false;
+
   MachineBasicBlock::const_reverse_iterator Pred(DbgValue);
   for (++Pred; Pred != MBB->rend(); ++Pred) {
     if (Pred->getFlag(MachineInstr::FrameSetup))
@@ -1505,11 +1518,6 @@
   if (!RangeEnd)
     return true;
 
-  // Fail if there are instructions belonging to our scope in another block.
-  const MachineInstr *LScopeEnd = LSRange.back().second;
-  if (LScopeEnd->getParent() != MBB)
-    return false;
-
   // Single, constant DBG_VALUEs in the prologue are promoted to be live
   // throughout the function. This is a hack, presumably for DWARF v2 and not
   // necessarily correct. It would be much better to use a dbg.declare instead


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