[DebugInfo][GlobalOpt] Fix -debugify for globalopt shrinking globals to booleans.

Summary:
TryToShrinkGlobalToBoolean, when possible, will split store <value> + load <value> into store <bool> + select <bool ? value : 0>. This preserves DebugLoc during that pass.

Fixes PR37959. The test case here is the simplified .ll for:

```
static int foo;
int bar() {
  foo = 5;
  return foo;
}
```

Reviewers: dblaikie, gbedwell, aprantl

Reviewed By: dblaikie

Subscribers: mehdi_amini, JDevlieghere, dexonsmith, llvm-commits

Tags: #debug-info

Differential Revision: https://reviews.llvm.org/D53531

llvm-svn: 345046

1 files changed, 9 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
index 5518ef8fce9..3005aafd06b 100644
--- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -1710,19 +1710,25 @@ static bool TryToShrinkGlobalToBoolean(GlobalVariable *GV, Constant *OtherVal) {
           assert(isa<LoadInst>(StoreVal) && "Not a load of NewGV!");
         }
       }
-      new StoreInst(StoreVal, NewGV, false, 0,
-                    SI->getOrdering(), SI->getSyncScopeID(), SI);
+      StoreInst *NSI =
+          new StoreInst(StoreVal, NewGV, false, 0, SI->getOrdering(),
+                        SI->getSyncScopeID(), SI);
+      NSI->setDebugLoc(SI->getDebugLoc());
     } else {
       // Change the load into a load of bool then a select.
       LoadInst *LI = cast<LoadInst>(UI);
       LoadInst *NLI = new LoadInst(NewGV, LI->getName()+".b", false, 0,
                                    LI->getOrdering(), LI->getSyncScopeID(), LI);
-      Value *NSI;
+      Instruction *NSI;
       if (IsOneZero)
         NSI = new ZExtInst(NLI, LI->getType(), "", LI);
       else
         NSI = SelectInst::Create(NLI, OtherVal, InitVal, "", LI);
       NSI->takeName(LI);
+      // Since LI is split into two instructions, NLI and NSI both inherit the
+      // same DebugLoc
+      NLI->setDebugLoc(LI->getDebugLoc());
+      NSI->setDebugLoc(LI->getDebugLoc());
       LI->replaceAllUsesWith(NSI);
     }
     UI->eraseFromParent();