Emit label names according to -discard-value-names.

[EricWF]

Summary

Previously, Clang only emitted label names in assert builds.
However there is a CC1 option -discard-value-names that should have been used to control emission instead.

This patch removes the NDEBUG preprocessor block and instead allows LLVM to handle removing the names in accordance with the option.

[aaron.ballman]

LGTM with a small formatting nit in the test.

test/CodeGenCXX/discard-name-values.cpp

17–21

Indentation is a bit off here. Actually, it seems off for much of the file -- can you reindent the comments as well?

[EricWF]

test/CodeGenCXX/discard-name-values.cpp

17–21

Ack. Clang-format to the rescue!

[EricWF]

• Address inline comments.

lib/CodeGen/CodeGenFunction.h

   static bool hasAggregateEvaluationKind(QualType T) {
     return getEvaluationKind(T) == TEK_Aggregate;
   }
 
   /// createBasicBlock - Create an LLVM basic block.
   llvm::BasicBlock *createBasicBlock(const Twine &name = "",
                                      llvm::Function *parent = nullptr,
                                      llvm::BasicBlock *before = nullptr) {
-#ifdef NDEBUG
-    return llvm::BasicBlock::Create(getLLVMContext(), "", parent, before);
-#else
     return llvm::BasicBlock::Create(getLLVMContext(), name, parent, before);
-#endif
   }
 
   /// getBasicBlockForLabel - Return the LLVM basicblock that the specified
   /// label maps to.
   JumpDest getJumpDestForLabel(const LabelDecl *S);
 
   /// SimplifyForwardingBlocks - If the given basic block is only a branch to
   /// another basic block, simplify it. This assumes that no other code could

test/CodeGenCXX/discard-name-values.cpp

-// RUN: %clang_cc1 -emit-llvm  -triple=armv7-apple-darwin -emit-llvm -std=c++11 %s -o - -O1 | FileCheck %s
-// RUN: %clang_cc1 -emit-llvm  -triple=armv7-apple-darwin -emit-llvm -std=c++11 %s -o - -O1 -discard-value-names | FileCheck %s --check-prefix=DISCARDVALUE
+// RUN: %clang_cc1 -emit-llvm  -triple=armv7-apple-darwin -std=c++11 %s -o - -O1 \
+// RUN:    | FileCheck %s
+// RUN: %clang_cc1 -emit-llvm -triple=armv7-apple-darwin -std=c++11 %s -o - -O1 \
+// RUN:    -discard-value-names | FileCheck %s --check-prefix=DISCARDVALUE
 
-int foo(int bar) {
-  return bar;
+extern "C" void branch();
+
+bool test(bool pred) {
+  // DISCARDVALUE: br i1 %0, label %2, label %3
+  // CHECK: br i1 %pred, label %if.then, label %if.end
+
+  if (pred) {
+    // DISCARDVALUE: ; <label>:2:
+    // DISCARDVALUE-NEXT: tail call void @branch()
+    // DISCARDVALUE-NEXT: br label %3
+
+    // CHECK: if.then:
+    // CHECK-NEXT: tail call void @branch()
+    // CHECK-NEXT: br label %if.end
+    branch();
   }
 
-// CHECK: ret i32 %bar
-// DISCARDVALUE: ret i32 %0
+  // DISCARDVALUE: ; <label>:3:
+  // DISCARDVALUE-NEXT: ret i1 %0
 
+  // CHECK: if.end:
+  // CHECK-NEXT: ret i1 %pred
+  return pred;
+}