[clang] Fix -fclang-abi-compat for clang 20

[Fznamznon]

The value was known already, but it was parsed as latest which is incorrect because we are already doing clang 21.

[llvmbot]

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-backend-x86

Author: Mariya Podchishchaeva (Fznamznon)

Changes

The value was known already, but it was parsed as latest which is incorrect because we are already doing clang 21.

---

Full diff: https://github.com/llvm/llvm-project/pull/144109.diff

2 Files Affected:

• (modified) clang/lib/Frontend/CompilerInvocation.cpp (+2)
• (modified) clang/test/CodeGen/X86/avx-cxx-record.cpp (+2)

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 2c02719121c73..9c0890713dc06 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -4475,6 +4475,8 @@ bool CompilerInvocation::ParseLangArgs(LangOptions &Opts, ArgList &Args,
         Opts.setClangABICompat(LangOptions::ClangABI::Ver18);
       else if (Major <= 19)
         Opts.setClangABICompat(LangOptions::ClangABI::Ver19);
+      else if (Major <= 20)
+        Opts.setClangABICompat(LangOptions::ClangABI::Ver20);
     } else if (Ver != "latest") {
       Diags.Report(diag::err_drv_invalid_value)
           << A->getAsString(Args) << A->getValue();
diff --git a/clang/test/CodeGen/X86/avx-cxx-record.cpp b/clang/test/CodeGen/X86/avx-cxx-record.cpp
index bcd9c361fda90..6ce6815a521a1 100644
--- a/clang/test/CodeGen/X86/avx-cxx-record.cpp
+++ b/clang/test/CodeGen/X86/avx-cxx-record.cpp
@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 %s -triple x86_64-unknown-linux-gnu -emit-llvm -O2 -target-cpu x86-64-v3 -o - | FileCheck %s
+// RUN: %clang_cc1 %s -triple x86_64-unknown-linux-gnu -emit-llvm -O2 -target-cpu x86-64-v3 -fclang-abi-compat=20 -o - | FileCheck --check-prefix CLANG-20 %s
 
 using UInt64x2 = unsigned long long __attribute__((__vector_size__(16), may_alias));
 
@@ -11,6 +12,7 @@ struct XMM2 : XMM1<0>, XMM1<1> {
 };
 
 // CHECK: define{{.*}} @_Z3foov({{.*}} [[ARG:%.*]]){{.*}}
+// CLANG-20: define{{.*}} <4 x double> @_Z3foov()
 // CHECK: entry:
 // CHECK-NEXT: store {{.*}}, ptr [[ARG]]{{.*}}
 // CHECK-NEXT: [[TMP1:%.*]] = getelementptr {{.*}}, ptr [[ARG]]{{.*}}

[Fznamznon]

I think this is the only test which is different between clang 20 and clang 21, hence the change.

[AaronBallman]

LGTM! It would be nice if we could find a way to make this easier as we put out releases though. This is super easy to forget to update after branching a release.