diff --git a/compiler-rt/lib/profile/CMakeLists.txt b/compiler-rt/lib/profile/CMakeLists.txt
--- a/compiler-rt/lib/profile/CMakeLists.txt
+++ b/compiler-rt/lib/profile/CMakeLists.txt
@@ -53,7 +53,6 @@
   InstrProfiling.c
   InstrProfilingInternal.c
   InstrProfilingValue.c
-  InstrProfilingBiasVar.c
   InstrProfilingBuffer.c
   InstrProfilingFile.c
   InstrProfilingMerge.c
diff --git a/compiler-rt/lib/profile/InstrProfiling.h b/compiler-rt/lib/profile/InstrProfiling.h
--- a/compiler-rt/lib/profile/InstrProfiling.h
+++ b/compiler-rt/lib/profile/InstrProfiling.h
@@ -320,10 +320,10 @@
 extern char INSTR_PROF_PROFILE_NAME_VAR[1]; /* __llvm_profile_filename. */
 
 /*!
- * This variable is a weak symbol defined in InstrProfilingBiasVar.c. It
- * allows compiler instrumentation to provide overriding definition with
- * value from compiler command line. This variable has hidden visibility.
+ * This variable is a weak external reference which could be used to detect
+ * whether or not the compiler defined this symbol.
  */
-COMPILER_RT_VISIBILITY extern intptr_t __llvm_profile_counter_bias;
+COMPILER_RT_VISIBILITY COMPILER_RT_WEAK extern intptr_t
+    __llvm_profile_counter_bias;
 
 #endif /* PROFILE_INSTRPROFILING_H_ */
diff --git a/compiler-rt/lib/profile/InstrProfilingBiasVar.c b/compiler-rt/lib/profile/InstrProfilingBiasVar.c
deleted file mode 100644
--- a/compiler-rt/lib/profile/InstrProfilingBiasVar.c
+++ /dev/null
@@ -1,15 +0,0 @@
-/*===- InstrProfilingBiasVar.c - profile counter bias variable setup ------===*\
-|*
-|* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-|* See https://llvm.org/LICENSE.txt for license information.
-|* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-|*
-\*===----------------------------------------------------------------------===*/
-
-#include "InstrProfiling.h"
-
-/* The runtime should only provide its own definition of this symbol when the
- * user has not specified one. Set this up by moving the runtime's copy of this
- * symbol to an object file within the archive.
- */
-COMPILER_RT_WEAK intptr_t __llvm_profile_counter_bias = -1;
diff --git a/compiler-rt/lib/profile/InstrProfilingFile.c b/compiler-rt/lib/profile/InstrProfilingFile.c
--- a/compiler-rt/lib/profile/InstrProfilingFile.c
+++ b/compiler-rt/lib/profile/InstrProfilingFile.c
@@ -999,7 +999,9 @@
   ProfileNameSpecifier PNS = PNS_unknown;
   int hasCommandLineOverrider = (INSTR_PROF_PROFILE_NAME_VAR[0] != 0);
 
-  if (__llvm_profile_counter_bias != -1)
+  /* This symbol is defined by the compiler when runtime counter relocation is
+   * used and runtime provides a weak external reference so we can check it. */
+  if (&__llvm_profile_counter_bias)
     lprofSetRuntimeCounterRelocation(1);
 
   EnvFilenamePat = getFilenamePatFromEnv();
diff --git a/compiler-rt/lib/profile/InstrProfilingPlatformFuchsia.c b/compiler-rt/lib/profile/InstrProfilingPlatformFuchsia.c
--- a/compiler-rt/lib/profile/InstrProfilingPlatformFuchsia.c
+++ b/compiler-rt/lib/profile/InstrProfilingPlatformFuchsia.c
@@ -116,10 +116,9 @@
     return;
   }
 
-  /* This symbol is defined as weak and initialized to -1 by the runtimer, but
-   * compiler will generate a strong definition initialized to 0 when runtime
-   * counter relocation is used. */
-  if (__llvm_profile_counter_bias == -1) {
+  /* This symbol is defined by the compiler when runtime counter relocation is
+   * used and runtime provides a weak external reference so we can check it. */
+  if (!&__llvm_profile_counter_bias) {
     lprofWrite("LLVM Profile: counter relocation at runtime is required\n");
     return;
   }
diff --git a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
--- a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -690,10 +690,19 @@
       Type *Int64Ty = Type::getInt64Ty(M->getContext());
       GlobalVariable *Bias = M->getGlobalVariable(getInstrProfCounterBiasVarName());
       if (!Bias) {
+        // Compiler must define this variable when runtime counter relocation
+        // is being used. Runtime has a weak external reference that is used
+        // to check whether that's the case or not.
         Bias = new GlobalVariable(*M, Int64Ty, false, GlobalValue::LinkOnceODRLinkage,
                                   Constant::getNullValue(Int64Ty),
                                   getInstrProfCounterBiasVarName());
         Bias->setVisibility(GlobalVariable::HiddenVisibility);
+        // A definition that's weak (linkonce_odr) without being in a COMDAT
+        // section wouldn't lead to link errors, but it would lead to a dead
+        // data word from every TU but one. Putting it in COMDAT ensures there
+        // will be exactly one data slot in the link.
+        if (TT.supportsCOMDAT())
+            Bias->setComdat(M->getOrInsertComdat(Bias->getName()));
       }
       LI = Builder.CreateLoad(Int64Ty, Bias);
     }
diff --git a/llvm/test/Instrumentation/InstrProfiling/runtime-counter-relocation.ll b/llvm/test/Instrumentation/InstrProfiling/runtime-counter-relocation.ll
--- a/llvm/test/Instrumentation/InstrProfiling/runtime-counter-relocation.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/runtime-counter-relocation.ll
@@ -4,7 +4,8 @@
 target triple = "x86_64-unknown-linux-gnu"
 
 @__profn_foo = private constant [3 x i8] c"foo"
-; RELOC: @__llvm_profile_counter_bias = linkonce_odr hidden global i64 0
+; RELOC: $__llvm_profile_counter_bias = comdat any
+; RELOC: @__llvm_profile_counter_bias = linkonce_odr hidden global i64 0, comdat
 
 ; CHECK-LABEL: define void @foo
 ; CHECK-NEXT: %pgocount = load i64, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc_foo, i64 0, i64 0)