[clang] [clang][AArch64] Don't #define __ARM_FEATURE_CRC32 when -crc is specified in -target-feature (PR #132167)

[via cfe-commits]

https://github.com/XiaShark created https://github.com/llvm/llvm-project/pull/132167

Currently, clang incorrectly defines the `__ARM_FEATURE_CRC32` macro even when `-crc` is explicitly specified in `-target-feature`. This can lead to unexpected behavior in code that relies on this macro.
See the example at https://godbolt.org/z/n4xsch3qv

This commit fixed the issue by adding a secondary check to confirm if `-crc` is specified in `-target-feature`.

>From 8ad45b1c02dc762752b13eed91d9ed5bd60bbefd Mon Sep 17 00:00:00 2001
From: XiaShark <xiajingze1 at huawei.com>
Date: Thu, 20 Mar 2025 14:32:30 +0800
Subject: [PATCH] [clang][AArch64] Don't #define __ARM_FEATURE_CRC32 when -crc
 is specified in -target-feature

Currently, clang incorrectly defines the `__ARM_FEATURE_CRC32` macro
even when `-crc` is explicitly specified in `-target-feature`. This can
lead to unexpected behavior in code that relies on this macro.

This commit fixed the issue by adding a secondary check to confirm if
`-crc` is specified in `-target-feature`.
---
 clang/lib/Basic/Targets/AArch64.cpp               | 8 +++++---
 clang/test/Preprocessor/aarch64-target-features.c | 2 ++
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/clang/lib/Basic/Targets/AArch64.cpp b/clang/lib/Basic/Targets/AArch64.cpp
index 3633bab6e0df9..f21e7d2c4d7b4 100644
--- a/clang/lib/Basic/Targets/AArch64.cpp
+++ b/clang/lib/Basic/Targets/AArch64.cpp
@@ -1192,17 +1192,19 @@ bool AArch64TargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
     }
   }
 
+  setDataLayout();
+  setArchFeatures();
+
   // Check features that are manually disabled by command line options.
   // This needs to be checked after architecture-related features are handled,
   // making sure they are properly disabled when required.
   for (const auto &Feature : Features) {
     if (Feature == "-d128")
       HasD128 = false;
+    if (Feature == "-crc")
+      HasCRC = false;
   }
 
-  setDataLayout();
-  setArchFeatures();
-
   if (HasNoFP) {
     FPU &= ~FPUMode;
     FPU &= ~NeonMode;
diff --git a/clang/test/Preprocessor/aarch64-target-features.c b/clang/test/Preprocessor/aarch64-target-features.c
index b10c55447d9af..6efad0f4983d7 100644
--- a/clang/test/Preprocessor/aarch64-target-features.c
+++ b/clang/test/Preprocessor/aarch64-target-features.c
@@ -120,7 +120,9 @@
 // RUN: %clang -target arm64-none-linux-gnu -march=armv8-a+crc -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-CRC32 %s
 // RUN: %clang -target aarch64-none-linux-gnu -march=armv8.1-a -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-CRC32 %s
 // RUN: %clang -target arm64-none-linux-gnu -march=armv8.1-a -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-CRC32 %s
+// RUN: %clang -target arm64-none-linux-gnu -march=armv8.1-a+nocrc -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-NOCRC %s
 // CHECK-CRC32: __ARM_FEATURE_CRC32 1
+// CHECK-NOCRC-NOT: __ARM_FEATURE_CRC32 1
 
 // RUN: %clang -target aarch64-none-linux-gnu -fno-math-errno -fno-signed-zeros\
 // RUN:        -fno-trapping-math -fassociative-math -freciprocal-math -fapprox-func\