diff --git a/llvm/include/llvm/Transforms/IPO/ImplementsAttrResolver.h b/llvm/include/llvm/Transforms/IPO/ImplementsAttrResolver.h
new file mode 100644
--- /dev/null
+++ b/llvm/include/llvm/Transforms/IPO/ImplementsAttrResolver.h
@@ -0,0 +1,27 @@
+//===- ImplementsAttrResolver.h - Repl. specification with impls. - C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// TODO
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_IPO_IMPLEMENTSATTRRESOLVER_H
+#define LLVM_TRANSFORMS_IPO_IMPLEMENTSATTRRESOLVER_H
+
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+
+struct ImplementsAttrResolverPass
+    : public PassInfoMixin<ImplementsAttrResolverPass> {
+  PreservedAnalyses run(Module &M, ModuleAnalysisManager &);
+};
+
+} // end namespace llvm
+
+#endif // LLVM_TRANSFORMS_IPO_DEADARGUMENTELIMINATION_H
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -106,6 +106,7 @@
 #include "llvm/Transforms/IPO/InferFunctionAttrs.h"
 #include "llvm/Transforms/IPO/Inliner.h"
 #include "llvm/Transforms/IPO/Internalize.h"
+#include "llvm/Transforms/IPO/ImplementsAttrResolver.h"
 #include "llvm/Transforms/IPO/LoopExtractor.h"
 #include "llvm/Transforms/IPO/LowerTypeTests.h"
 #include "llvm/Transforms/IPO/MergeFunctions.h"
@@ -278,6 +279,10 @@
     "enable-npm-O3-nontrivial-unswitch", cl::init(true), cl::Hidden,
     cl::ZeroOrMore, cl::desc("Enable non-trivial loop unswitching for -O3"));
 
+static cl::opt<bool> EnableImplementsAttrResolver(
+    "enable-implements-attr-resolver", cl::init(false), cl::Hidden,
+    cl::ZeroOrMore, cl::desc("Enable the implements attribute resolver"));
+
 PipelineTuningOptions::PipelineTuningOptions() {
   LoopInterleaving = true;
   LoopVectorization = true;
@@ -1131,6 +1136,12 @@
   // globals.
   MPM.addPass(DeadArgumentEliminationPass());
 
+  // Replace calls to functions specifications with their "implementation".
+  // See the `implements` and `specification` clang attributes and the
+  // `implements` LLVM-IR attribute.
+  if (EnableImplementsAttrResolver)
+    MPM.addPass(ImplementsAttrResolverPass());
+
   // Create a small function pass pipeline to cleanup after all the global
   // optimizations.
   FunctionPassManager GlobalCleanupPM(DebugLogging);
@@ -1659,6 +1670,12 @@
   // is fixed.
   MPM.addPass(WholeProgramDevirtPass(ExportSummary, nullptr));
 
+  // Replace calls to functions specifications with their "implementation".
+  // See the `implements` and `specification` clang attributes and the
+  // `implements` LLVM-IR attribute.
+  if (EnableImplementsAttrResolver)
+    MPM.addPass(ImplementsAttrResolverPass());
+
   // Stop here at -O1.
   if (Level == OptimizationLevel::O1) {
     // The LowerTypeTestsPass needs to run to lower type metadata and the
@@ -1892,6 +1909,12 @@
   MPM.addPass(AlwaysInlinerPass(
       /*InsertLifetimeIntrinsics=*/PTO.Coroutines));
 
+  // Replace calls to functions specifications with their "implementation".
+  // See the `implements` and `specification` clang attributes and the
+  // `implements` LLVM-IR attribute.
+  if (EnableImplementsAttrResolver)
+    MPM.addPass(ImplementsAttrResolverPass());
+
   if (PTO.MergeFunctions)
     MPM.addPass(MergeFunctionsPass());
 
diff --git a/llvm/lib/Passes/PassRegistry.def b/llvm/lib/Passes/PassRegistry.def
--- a/llvm/lib/Passes/PassRegistry.def
+++ b/llvm/lib/Passes/PassRegistry.def
@@ -71,6 +71,7 @@
 MODULE_PASS("instrprof", InstrProfiling())
 MODULE_PASS("internalize", InternalizePass())
 MODULE_PASS("invalidate<all>", InvalidateAllAnalysesPass())
+MODULE_PASS("implements-attr-resolver", ImplementsAttrResolverPass())
 MODULE_PASS("ipsccp", IPSCCPPass())
 MODULE_PASS("iroutliner", IROutlinerPass())
 MODULE_PASS("print-ir-similarity", IRSimilarityAnalysisPrinterPass(dbgs()))
diff --git a/llvm/lib/Transforms/IPO/CMakeLists.txt b/llvm/lib/Transforms/IPO/CMakeLists.txt
--- a/llvm/lib/Transforms/IPO/CMakeLists.txt
+++ b/llvm/lib/Transforms/IPO/CMakeLists.txt
@@ -25,6 +25,7 @@
   InlineSimple.cpp
   Inliner.cpp
   Internalize.cpp
+  ImplementsAttrResolver.cpp
   LoopExtractor.cpp
   LowerTypeTests.cpp
   MergeFunctions.cpp
diff --git a/llvm/lib/Transforms/IPO/ImplementsAttrResolver.cpp b/llvm/lib/Transforms/IPO/ImplementsAttrResolver.cpp
new file mode 100644
--- /dev/null
+++ b/llvm/lib/Transforms/IPO/ImplementsAttrResolver.cpp
@@ -0,0 +1,44 @@
+//===- ImplementsAttrResolver.cpp - Repl. specifications w implemenations -===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// TODO
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/IPO/ImplementsAttrResolver.h"
+
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/PassInstrumentation.h"
+
+#define DEBUG_TYPE "implements-attr-resolver"
+
+using namespace llvm;
+
+PreservedAnalyses ImplementsAttrResolverPass::run(Module &M,
+                                                  ModuleAnalysisManager &) {
+  for (Function &Impl : M) {
+    const Attribute &A = Impl.getFnAttribute("implements");
+    if (!A.isValid())
+      continue;
+
+    const StringRef SpecificationName = A.getValueAsString();
+    Function *Specification = M.getFunction(SpecificationName);
+    if (!Specification) {
+      LLVM_DEBUG(dbgs() << "Found implementation '" << Impl.getName()
+                        << "' but no matching specification with name '"
+                        << SpecificationName
+                        << "', potentially inlined and/or eliminated.\n");
+      continue;
+    }
+    LLVM_DEBUG(dbgs() << "Replace specification '" << Specification->getName()
+                      << "' with implementation '" << Impl.getName() << "'\n");
+    Specification->replaceAllUsesWith(
+        ConstantExpr::getBitCast(&Impl, Specification->getType()));
+  }
+  return PreservedAnalyses::all();
+}
diff --git a/llvm/test/Transforms/ImplementsAttrResolver/intrinsic_implementation.ll b/llvm/test/Transforms/ImplementsAttrResolver/intrinsic_implementation.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Transforms/ImplementsAttrResolver/intrinsic_implementation.ll
@@ -0,0 +1,38 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes=implements-attr-resolver -S | FileCheck %s
+
+@llvm.compiler.used = appending global [2 x i8*] [i8* bitcast (float (float)* @my_sin to i8*), i8* bitcast (float (float)* @my_cos_type_mismatch to i8*)], section "llvm.metadata"
+
+define internal float @my_sin(float %d) "implements"="llvm.sin.f32" {
+; CHECK-LABEL: @my_sin(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    ret float [[D:%.*]]
+;
+entry:
+  ret float %d
+}
+
+define internal float @my_cos_type_mismatch(float %d) "implements"="llvm.cos.f64" {
+; CHECK-LABEL: @my_cos_type_mismatch(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    ret float [[D:%.*]]
+;
+entry:
+  ret float %d
+}
+
+define double @foo(double %d, float %f) {
+; CHECK-LABEL: @foo(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[TMP0:%.*]] = tail call fast float @my_sin(float [[F:%.*]])
+; CHECK-NEXT:    [[TMP1:%.*]] = tail call fast double bitcast (float (float)* @my_cos_type_mismatch to double (double)*)(double [[D:%.*]])
+; CHECK-NEXT:    ret double [[TMP1]]
+;
+entry:
+  %0 = tail call fast float @llvm.sin.f32(float %f)
+  %1 = tail call fast double @llvm.cos.f64(double %d)
+  ret double %1
+}
+
+declare float @llvm.sin.f32(float)
+declare double @llvm.cos.f64(double)