[DCE] Add DebugCounter support

Patch by Zhizhou Yang!

Differential Revision: https://reviews.llvm.org/D50092

llvm-svn: 342170

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Scalar/DCE.cpp b/llvm/lib/Transforms/Scalar/DCE.cpp
index 6078967a0f9..4c964e6e888 100644
--- a/llvm/lib/Transforms/Scalar/DCE.cpp
+++ b/llvm/lib/Transforms/Scalar/DCE.cpp
@@ -24,6 +24,7 @@
 #include "llvm/IR/InstIterator.h"
 #include "llvm/IR/Instruction.h"
 #include "llvm/Pass.h"
+#include "llvm/Support/DebugCounter.h"
 #include "llvm/Transforms/Scalar.h"
 using namespace llvm;
 
@@ -31,6 +32,8 @@ using namespace llvm;
 
 STATISTIC(DIEEliminated, "Number of insts removed by DIE pass");
 STATISTIC(DCEEliminated, "Number of insts removed");
+DEBUG_COUNTER(DCECounter, "dce-transform",
+              "Controls which instructions are eliminated");
 
 namespace {
   //===--------------------------------------------------------------------===//
@@ -50,6 +53,8 @@ namespace {
       for (BasicBlock::iterator DI = BB.begin(); DI != BB.end(); ) {
         Instruction *Inst = &*DI++;
         if (isInstructionTriviallyDead(Inst, TLI)) {
+          if (!DebugCounter::shouldExecute(DCECounter))
+            continue;
           salvageDebugInfo(*Inst);
           Inst->eraseFromParent();
           Changed = true;
@@ -77,6 +82,9 @@ static bool DCEInstruction(Instruction *I,
                            SmallSetVector<Instruction *, 16> &WorkList,
                            const TargetLibraryInfo *TLI) {
   if (isInstructionTriviallyDead(I, TLI)) {
+    if (!DebugCounter::shouldExecute(DCECounter))
+      return false;
+
     salvageDebugInfo(*I);
 
     // Null out all of the instruction's operands to see if any operand becomes