commit 31ec356a488a364c55782e82691afd1b8f449bc5
author Vedant Kumar <vsk@apple.com> Tue Feb 13 01:09:49 2018 +0000
committer Vedant Kumar <vsk@apple.com> Tue Feb 13 01:09:49 2018 +0000
tree a32bae600764f8af2d9edbd8108e647395db7816
parent 47b16c45d7acef402729e67d66aebafe5295af75

[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

llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
index 889250e..885e588 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
@@ -347,6 +347,9 @@
     case dwarf::DW_OP_mul:
     case dwarf::DW_OP_or:
     case dwarf::DW_OP_xor:
+    case dwarf::DW_OP_shl:
+    case dwarf::DW_OP_shr:
+    case dwarf::DW_OP_shra:
       emitOp(Op->getOp());
       break;
     case dwarf::DW_OP_deref:

llvm/lib/IR/DebugInfoMetadata.cpp

diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index 91b965c..fc3d344 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -710,6 +710,9 @@
     case dwarf::DW_OP_mul:
     case dwarf::DW_OP_or:
     case dwarf::DW_OP_xor:
+    case dwarf::DW_OP_shl:
+    case dwarf::DW_OP_shr:
+    case dwarf::DW_OP_shra:
     case dwarf::DW_OP_deref:
     case dwarf::DW_OP_xderef:
       break;

llvm/lib/Transforms/Utils/Local.cpp

diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 379b6bf..1340e12 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -1555,6 +1555,15 @@
       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;