[VPlan] Do not print mapping for Value2VPValue.

The latest improvements to VPValue printing make this mapping clear when
printing the operand. Printing the mapping separately is not required
any longer.

Reviewers: rengolin, hsaito, Ayal, gilr

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D76375

llvm/lib/Transforms/Vectorize/VPlan.cpp

@@ -580,19 +580,10 @@ void VPlanPrinter::dump() {
   OS << "graph [labelloc=t, fontsize=30; label=\"Vectorization Plan";
   if (!Plan.getName().empty())
     OS << "\\n" << DOT::EscapeString(Plan.getName());
-  if (!Plan.Value2VPValue.empty() || Plan.BackedgeTakenCount) {
-    OS << ", where:";
-    if (Plan.BackedgeTakenCount) {
-      OS << "\\n";
-      Plan.BackedgeTakenCount->print(OS, SlotTracker);
-      OS << " := BackedgeTakenCount";
-    }
-    for (auto Entry : Plan.Value2VPValue) {
-      OS << "\\n";
-      Entry.second->print(OS, SlotTracker);
-      OS << DOT::EscapeString(" := ");
-      Entry.first->printAsOperand(OS, false);
-    }
+  if (Plan.BackedgeTakenCount) {
+    OS << ", where:\\n";
+    Plan.BackedgeTakenCount->print(OS, SlotTracker);
+    OS << " := BackedgeTakenCount";
   }
   OS << "\"]\n";
   OS << "node [shape=rect, fontname=Courier, fontsize=30]\n";

llvm/unittests/Transforms/Vectorize/VPlanHCFGTest.cpp

@@ -89,6 +89,9 @@ TEST_F(VPlanHCFGTest, testBuildHCFGInnerLoop) {
   EXPECT_EQ(IndvarAdd, ICmp->getOperand(0));
   EXPECT_EQ(VecBB->getCondBit(), ICmp);
 
+  // Add an external value to check we do not print the list of external values,
+  // as this is not required with the new printing.
+  Plan->addVPValue(&*F->arg_begin());
   std::string FullDump;
   raw_string_ostream(FullDump) << *Plan;
   EXPECT_EQ(R"(digraph VPlan {