[Utils] Salvage debug info of DCE'ed shl/lhsr/ashr instructions

Here are the number of additional debug values salvaged in a stage2
build of clang:

  1912 SALVAGE: ASHR
   405 SALVAGE: LSHR
   249 SALVAGE: SHL

llvm-svn: 324975

1 files changed, 9 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 379b6bf1311..1340e12c5c6 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -1555,6 +1555,15 @@ void llvm::salvageDebugInfo(Instruction &I) {
       case Instruction::Xor:
         applyOps(DII, {dwarf::DW_OP_constu, Val, dwarf::DW_OP_xor});
         break;
+      case Instruction::Shl:
+        applyOps(DII, {dwarf::DW_OP_constu, Val, dwarf::DW_OP_shl});
+        break;
+      case Instruction::LShr:
+        applyOps(DII, {dwarf::DW_OP_constu, Val, dwarf::DW_OP_shr});
+        break;
+      case Instruction::AShr:
+        applyOps(DII, {dwarf::DW_OP_constu, Val, dwarf::DW_OP_shra});
+        break;
       default:
         // TODO: Salvage constants from each kind of binop we know about.
         continue;