From 1d5d31b70666e4b78f4cf4b837c17c9c3bbb53b3 Mon Sep 17 00:00:00 2001
From: Vedant Kumar <vsk@apple.com>
Date: Tue, 13 Feb 2018 22:27:17 +0000
Subject: [GVN] Salvage debug info from dead insts

This preserves an additional 581 unique source variables in a stage2
build of clang (according to `llvm-dwarfdump --statistics`). It
increases the size of the .debug_loc section by 0.1% (or 87139 bytes).

Differential Revision: https://reviews.llvm.org/D43255

llvm-svn: 325063
---
 llvm/lib/Transforms/Scalar/GVN.cpp | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'llvm/lib/Transforms')

diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp
index e2c1eaf58e4..a9104408691 100644
--- a/llvm/lib/Transforms/Scalar/GVN.cpp
+++ b/llvm/lib/Transforms/Scalar/GVN.cpp
@@ -2105,6 +2105,7 @@ bool GVN::processBlock(BasicBlock *BB) {
     for (auto *I : InstrsToErase) {
       assert(I->getParent() == BB && "Removing instruction from wrong block?");
       DEBUG(dbgs() << "GVN removed: " << *I << '\n');
+      salvageDebugInfo(*I);
       if (MD) MD->removeInstruction(I);
       DEBUG(verifyRemoved(I));
       if (MaybeFirstICF == I) {
@@ -2320,6 +2321,7 @@ bool GVN::performScalarPRE(Instruction *CurInst) {
   VN.eraseTranslateCacheEntry(ValNo, *CurrentBlock);
   addToLeaderTable(ValNo, Phi, CurrentBlock);
   Phi->setDebugLoc(CurInst->getDebugLoc());
+  salvageDebugInfo(*CurInst);
   CurInst->replaceAllUsesWith(Phi);
   if (MD && Phi->getType()->isPtrOrPtrVectorTy())
     MD->invalidateCachedPointerInfo(Phi);
-- 
cgit v1.2.3