https://github.com/yamash-fj created https://github.com/llvm/llvm-project/pull/203458
Fix #192186. An explicit ``+nofeat`` of ``-mcpu`` option is ignored when the feature is implied by the base-architecture. Two approaches were considerd: 1. include architechture-implied features in the ``CPUExtension`` set 2. preserve explicit user ``+nofeat`` even for architecture-implied features , and this patch implements the latter. When checking CPU extensions, simultaneously set ``Enabled`` flags for the base-architecture's default extensions. By setting ``Enabled``, an explicit +nofeat disables the feature and marks it as ``Touched``, and it prevents ``-feat`` from going away. Behaivior changes: For architecuture-default features: - preserve explicit ``+nofeat``(#192186). - remove redundant ``+feat``. I'm not sure whether this behaivior is intentional. Please tell me if I misunderstand. >From a443cce306bd40fe24155cd1b057c3399961f3f6 Mon Sep 17 00:00:00 2001 From: yamash-fj <[email protected]> Date: Fri, 12 Jun 2026 13:52:40 +0900 Subject: [PATCH] [AArch64][Driver] Fix behavior of +nofeat modifier Fix #192186. An explicit ``+nofeat`` of ``-mcpu`` option is ignored when the feature is implied by the base-architecture. Two approaches were considerd: 1. include architechture-implied features in the ``CPUExtension`` set 2. preserve explicit user ``+nofeat`` even for architecture-implied features , and this patch implements the latter. When checking CPU extensions, simultaneously set ``Enabled`` flags for the base-architecture's default extensions. By setting ``Enabled``, an explicit +nofeat disables the feature and marks it as ``Touched``, and it prevents ``-feat`` from going away. Behaivior changes: For architecuture-default features: - preserve explicit ``+nofeat``(#192186). - remove redundant ``+feat``. --- clang/test/Driver/aarch64-no-feat.c | 31 +++++++++++++++++++ llvm/lib/TargetParser/AArch64TargetParser.cpp | 9 +++++- 2 files changed, 39 insertions(+), 1 deletion(-) create mode 100644 clang/test/Driver/aarch64-no-feat.c diff --git a/clang/test/Driver/aarch64-no-feat.c b/clang/test/Driver/aarch64-no-feat.c new file mode 100644 index 0000000000000..ef3472b3a63e0 --- /dev/null +++ b/clang/test/Driver/aarch64-no-feat.c @@ -0,0 +1,31 @@ +// RUN: %clang --target=aarch64-linux-gnu -mcpu=neoverse-v2 %s -### 2>&1 | FileCheck %s --check-prefix=NEOVERSE-V2-DEFAULT +// NEOVERSE-V2-DEFAULT-NOT: "-target-feature" "+sb" +// NEOVERSE-V2-DEFAULT-NOT: "-target-feature" "-sb" +// NEOVERSE-V2-DEFAULT: "-target-feature" "+rand" +// NEOVERSE-V2-DEFAULT-SAME: "-target-feature" "+sve" +// NEOVERSE-V2-DEFAULT-NOT: "-target-feature" "+sha2" + +// RUN: %clang --target=aarch64-linux-gnu -mcpu=neoverse-v2+nosb %s -### 2>&1 | FileCheck %s --check-prefix=NEOVERSE-V2-NOSB +// NEOVERSE-V2-NOSB: "-target-feature" "-sb" + +// RUN: %clang --target=aarch64-linux-gnu -mcpu=neoverse-v2+sb %s -### 2>&1 | FileCheck %s --check-prefix=NEOVERSE-V2-SB +// NEOVERSE-V2-SB-NOT: "-target-feature" "+sb" + +// RUN: %clang --target=aarch64-linux-gnu -mcpu=neoverse-v2+nosve %s -### 2>&1 | FileCheck %s --check-prefix=NEOVERSE-V2-NOSVE +// NEOVERSE-V2-NOSVE: "-target-feature" "-sve" + +// RUN: %clang --target=aarch64-linux-gnu -mcpu=neoverse-v2+sve %s -### 2>&1 | FileCheck %s --check-prefix=NEOVERSE-V2-SVE +// NEOVERSE-V2-SVE: "-target-feature" "+sve" + +// RUN: %clang --target=aarch64-linux-gnu -mcpu=neoverse-v2+norng %s -### 2>&1 | FileCheck %s --check-prefix=NEOVERSE-V2-NORNG +// NEOVERSE-V2-NORNG: "-target-feature" "-rand" + +// RUN: %clang --target=aarch64-linux-gnu -mcpu=neoverse-v2+rng %s -### 2>&1 | FileCheck %s --check-prefix=NEOVERSE-V2-RNG +// NEOVERSE-V2-RNG: "-target-feature" "+rand" + +// RUN: %clang --target=aarch64-linux-gnu -mcpu=neoverse-v2+nosha2 %s -### 2>&1 | FileCheck %s --check-prefix=NEOVERSE-V2-NOSHA2 +// NEOVERSE-V2-NOSHA2-NOT: "-target-feature" "+sha2" +// NEOVERSE-V2-NOSHA2-NOT: "-target-feature" "-sha2" + +// RUN: %clang --target=aarch64-linux-gnu -mcpu=neoverse-v2+sha2 %s -### 2>&1 | FileCheck %s --check-prefix=NEOVERSE-V2-SHA2 +// NEOVERSE-V2-SHA2: "-target-feature" "+sha2" diff --git a/llvm/lib/TargetParser/AArch64TargetParser.cpp b/llvm/lib/TargetParser/AArch64TargetParser.cpp index 2c0211b3a2919..2938c40139eb7 100644 --- a/llvm/lib/TargetParser/AArch64TargetParser.cpp +++ b/llvm/lib/TargetParser/AArch64TargetParser.cpp @@ -340,14 +340,21 @@ void AArch64::ExtensionSet::disable(ArchExtKind E) { disable(Dep.Later); } +static void setEnableIfMandatory(AArch64::ExtensionSet &Exts, AArch64::ExtensionInfo E) { + if (Exts.BaseArch->DefaultExts.test(E.ID)) + Exts.Enabled.set(E.ID); +} + void AArch64::ExtensionSet::addCPUDefaults(const CpuInfo &CPU) { LLVM_DEBUG(llvm::dbgs() << "addCPUDefaults(" << CPU.Name << ")\n"); BaseArch = &CPU.Arch; AArch64::ExtensionBitset CPUExtensions = CPU.getImpliedExtensions(); - for (const auto &E : Extensions) + for (const auto &E : Extensions) { if (CPUExtensions.test(E.ID)) enable(E.ID); + setEnableIfMandatory(*this, E); + } } void AArch64::ExtensionSet::addArchDefaults(const ArchInfo &Arch) { _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
