From 2aba2f1d8bfad031ae59ea5dfec8b65978f908a0 Mon Sep 17 00:00:00 2001
From: Florian Mayer <fmayer@google.com>
Date: Thu, 19 Mar 2026 17:28:48 -0700
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
 =?UTF-8?q?l=20version?=
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Created using spr 1.3.7
---
 clang/lib/Serialization/ASTReader.cpp        |  3 +++
 clang/test/Modules/merge-target-features.cpp | 21 ++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 03b1b02859b81..db4fa68f6db08 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -495,7 +495,10 @@ static bool checkTargetOptions(const TargetOptions &TargetOpts,
   SmallVector<StringRef, 4> ReadFeatures(TargetOpts.FeaturesAsWritten.begin(),
                                          TargetOpts.FeaturesAsWritten.end());
   llvm::sort(ExistingFeatures);
+  ExistingFeatures.erase(llvm::unique(ExistingFeatures),
+                         ExistingFeatures.end());
   llvm::sort(ReadFeatures);
+  ReadFeatures.erase(llvm::unique(ReadFeatures), ReadFeatures.end());
 
   // We compute the set difference in both directions explicitly so that we can
   // diagnose the differences differently.
diff --git a/clang/test/Modules/merge-target-features.cpp b/clang/test/Modules/merge-target-features.cpp
index 73474e1388fb6..01d38a1eb0d13 100644
--- a/clang/test/Modules/merge-target-features.cpp
+++ b/clang/test/Modules/merge-target-features.cpp
@@ -10,6 +10,15 @@
 // RUN:   -target-cpu i386 -target-feature +sse2 \
 // RUN:   Inputs/merge-target-features/module.modulemap
 //
+// RUN: %clang_cc1 -fmodules -x c++ -fmodules-cache-path=%t \
+// RUN:   -iquote Inputs/merge-target-features \
+// RUN:   -fno-implicit-modules \
+// RUN:   -fmodule-map-file-home-is-cwd \
+// RUN:   -emit-module -fmodule-name=foo -o %t/foo-double.pcm \
+// RUN:   -triple i386-unknown-unknown \
+// RUN:   -target-cpu i386 -target-feature +sse2 -target-feature +sse2 \
+// RUN:   Inputs/merge-target-features/module.modulemap
+//
 // RUN: not %clang_cc1 -fmodules -x c++ -fmodules-cache-path=%t \
 // RUN:   -iquote Inputs/merge-target-features \
 // RUN:   -fno-implicit-modules \
@@ -60,6 +69,18 @@
 // MISMATCH: error: precompiled file '{{.*}}foo.pcm' was compiled with the target feature '+sse2' but the current translation unit is not
 // MISMATCH: error: current translation unit is compiled with the target feature '+cx16' but the precompiled file '{{.*}}foo.pcm' was not
 // MISMATCH: error: {{.*}} configuration mismatch
+//
+// RUN: %clang_cc1 -fmodules -x c++ -fmodules-cache-path=%t \
+// RUN:   -iquote Inputs/merge-target-features \
+// RUN:   -fno-implicit-modules \
+// RUN:   -fmodule-map-file-home-is-cwd \
+// RUN:   -fmodule-map-file=Inputs/merge-target-features/module.modulemap \
+// RUN:   -fmodule-file=%t/foo-double.pcm \
+// RUN:   -triple i386-unknown-unknown \
+// RUN:   -target-cpu i386 -target-feature +sse2 \
+// RUN:   -fsyntax-only merge-target-features.cpp 2>&1 \
+// RUN:   | FileCheck --allow-empty --check-prefix=DOUBLE %s
+// DOUBLE-NOT: error:
 
 #include "foo.h"