Bugfix for the debug intrinsic handling in InstCombiner:
Since we can't guarantee that the original dbg.declare instrinsic
is removed by LowerDbgDeclare(), we need to make sure that we are
not inserting the same dbg.value intrinsic over and over.
This removes tons of redundant DIEs when compiling optimized code.
rdar://problem/13056109
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180615 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp
index be80d34..70dae33 100644
--- a/lib/Transforms/Utils/Local.cpp
+++ b/lib/Transforms/Utils/Local.cpp
@@ -832,7 +832,24 @@
/// Dbg Intrinsic utilities
///
-/// Inserts a llvm.dbg.value instrinsic before the stores to an alloca'd value
+/// See if there is a dbg.value intrinsic for DIVar before I.
+static bool LdStHasDebugValue(DIVariable &DIVar, Instruction *I) {
+ // Since we can't guarantee that the original dbg.declare instrinsic
+ // is removed by LowerDbgDeclare(), we need to make sure that we are
+ // not inserting the same dbg.value intrinsic over and over.
+ llvm::BasicBlock::InstListType::iterator PrevI(I);
+ if (PrevI != I->getParent()->getInstList().begin()) {
+ --PrevI;
+ if (DbgValueInst *DVI = dyn_cast<DbgValueInst>(PrevI))
+ if (DVI->getValue() == I->getOperand(0) &&
+ DVI->getOffset() == 0 &&
+ DVI->getVariable() == DIVar)
+ return true;
+ }
+ return false;
+}
+
+/// Inserts a llvm.dbg.value instrinsic before a store to an alloca'd value
/// that has an associated llvm.dbg.decl intrinsic.
bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
StoreInst *SI, DIBuilder &Builder) {
@@ -840,6 +857,9 @@
if (!DIVar.Verify())
return false;
+ if (LdStHasDebugValue(DIVar, SI))
+ return true;
+
Instruction *DbgVal = NULL;
// If an argument is zero extended then use argument directly. The ZExt
// may be zapped by an optimization pass in future.
@@ -863,7 +883,7 @@
return true;
}
-/// Inserts a llvm.dbg.value instrinsic before the stores to an alloca'd value
+/// Inserts a llvm.dbg.value instrinsic before a load of an alloca'd value
/// that has an associated llvm.dbg.decl intrinsic.
bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
LoadInst *LI, DIBuilder &Builder) {
@@ -871,6 +891,9 @@
if (!DIVar.Verify())
return false;
+ if (LdStHasDebugValue(DIVar, LI))
+ return true;
+
Instruction *DbgVal =
Builder.insertDbgValueIntrinsic(LI->getOperand(0), 0,
DIVar, LI);
@@ -902,6 +925,8 @@
E = Dbgs.end(); I != E; ++I) {
DbgDeclareInst *DDI = *I;
if (AllocaInst *AI = dyn_cast_or_null<AllocaInst>(DDI->getAddress())) {
+ // We only remove the dbg.declare intrinsic if all uses are
+ // converted to dbg.value intrinsics.
bool RemoveDDI = true;
for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end();
UI != E; ++UI)