[clang] [Clang] Remove preprocessor guards and global feature checks for NEON (PR #95102)

[via cfe-commits]

https://github.com/Lukacma created https://github.com/llvm/llvm-project/pull/95102

To enable function multi-versioning (FMV), current checks which rely on cmd line options or global macros to see if target feature is present need to be removed. This patch removes those for NEON and also implements changes to NEON header file as proposed in [ACLE](https://github.com/ARM-software/acle/pull/321).

>From cdffede6773ae1bdbe759d636f582a9218522c32 Mon Sep 17 00:00:00 2001
From: Marian Lukac <Marian.Lukac at arm.com>
Date: Tue, 11 Jun 2024 11:00:42 +0000
Subject: [PATCH] [Clang] Remove preprocessor guards and global feature checks
 for NEON

---
 clang/lib/Sema/SemaType.cpp                | 23 ----------------------
 clang/test/Sema/arm-vector-types-support.c |  2 --
 clang/test/SemaCUDA/neon-attrs.cu          | 22 ---------------------
 clang/utils/TableGen/NeonEmitter.cpp       |  5 -----
 4 files changed, 52 deletions(-)
 delete mode 100644 clang/test/SemaCUDA/neon-attrs.cu

diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 441fdcca0758f..65b87f62e294f 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -8084,29 +8084,6 @@ static void HandleNeonVectorTypeAttr(QualType &CurType, const ParsedAttr &Attr,
         AuxTI && (AuxTI->getTriple().isAArch64() || AuxTI->getTriple().isARM());
   }
 
-  // Target must have NEON (or MVE, whose vectors are similar enough
-  // not to need a separate attribute)
-  if (!(S.Context.getTargetInfo().hasFeature("neon") ||
-        S.Context.getTargetInfo().hasFeature("mve") ||
-        S.Context.getTargetInfo().hasFeature("sve") ||
-        S.Context.getTargetInfo().hasFeature("sme") ||
-        IsTargetCUDAAndHostARM) &&
-      VecKind == VectorKind::Neon) {
-    S.Diag(Attr.getLoc(), diag::err_attribute_unsupported)
-        << Attr << "'neon', 'mve', 'sve' or 'sme'";
-    Attr.setInvalid();
-    return;
-  }
-  if (!(S.Context.getTargetInfo().hasFeature("neon") ||
-        S.Context.getTargetInfo().hasFeature("mve") ||
-        IsTargetCUDAAndHostARM) &&
-      VecKind == VectorKind::NeonPoly) {
-    S.Diag(Attr.getLoc(), diag::err_attribute_unsupported)
-        << Attr << "'neon' or 'mve'";
-    Attr.setInvalid();
-    return;
-  }
-
   // Check the attribute arguments.
   if (Attr.getNumArgs() != 1) {
     S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments)
diff --git a/clang/test/Sema/arm-vector-types-support.c b/clang/test/Sema/arm-vector-types-support.c
index ed5f5ba175a94..1d2e1c9336fc6 100644
--- a/clang/test/Sema/arm-vector-types-support.c
+++ b/clang/test/Sema/arm-vector-types-support.c
@@ -2,6 +2,4 @@
 // RUN: %clang_cc1 %s -triple aarch64 -fsyntax-only -verify
 // RUN: %clang_cc1 %s -triple aarch64 -target-feature -fp-armv8 -target-abi aapcs-soft -fsyntax-only -verify
 
-typedef __attribute__((neon_vector_type(2))) int int32x2_t; // expected-error{{'neon_vector_type' attribute is not supported on targets missing 'neon', 'mve', 'sve' or 'sme'; specify an appropriate -march= or -mcpu=}}
-typedef __attribute__((neon_polyvector_type(16))) short poly8x16_t; // expected-error{{'neon_polyvector_type' attribute is not supported on targets missing 'neon' or 'mve'; specify an appropriate -march= or -mcpu=}}
 typedef __attribute__((arm_sve_vector_bits(256))) void nosveflag; // expected-error{{'arm_sve_vector_bits' attribute is not supported on targets missing 'sve'; specify an appropriate -march= or -mcpu=}}
diff --git a/clang/test/SemaCUDA/neon-attrs.cu b/clang/test/SemaCUDA/neon-attrs.cu
deleted file mode 100644
index 129056741ac9a..0000000000000
--- a/clang/test/SemaCUDA/neon-attrs.cu
+++ /dev/null
@@ -1,22 +0,0 @@
-// CPU-side compilation on ARM with neon enabled (no errors expected).
-// RUN: %clang_cc1 -triple arm64-linux-gnu -target-feature +neon -aux-triple nvptx64 -x cuda -fsyntax-only -verify=quiet %s
-
-// CPU-side compilation on ARM with neon disabled.
-// RUN: %clang_cc1 -triple arm64-linux-gnu -target-feature -neon -aux-triple nvptx64 -x cuda -fsyntax-only -verify %s
-
-// GPU-side compilation on ARM (no errors expected).
-// RUN: %clang_cc1 -triple nvptx64 -aux-triple arm64-linux-gnu -fcuda-is-device -x cuda -fsyntax-only -verify=quiet %s
-
-// Regular C++ compilation on ARM with neon enabled (no errors expected).
-// RUN: %clang_cc1 -triple arm64-linux-gnu -target-feature +neon -x c++ -fsyntax-only -verify=quiet %s
-
-// Regular C++ compilation on ARM with neon disabled.
-// RUN: %clang_cc1 -triple arm64-linux-gnu -target-feature -neon -x c++ -fsyntax-only -verify %s
-
-// quiet-no-diagnostics
-typedef __attribute__((neon_vector_type(4))) float float32x4_t;
-// expected-error at -1 {{'neon_vector_type' attribute is not supported on targets missing 'neon', 'mve', 'sve' or 'sme'}}
-// expect
-typedef unsigned char poly8_t;
-typedef __attribute__((neon_polyvector_type(8))) poly8_t poly8x8_t;
-// expected-error at -1 {{'neon_polyvector_type' attribute is not supported on targets missing 'neon' or 'mve'}}
diff --git a/clang/utils/TableGen/NeonEmitter.cpp b/clang/utils/TableGen/NeonEmitter.cpp
index 56f1fdf9ef574..626031d38cf00 100644
--- a/clang/utils/TableGen/NeonEmitter.cpp
+++ b/clang/utils/TableGen/NeonEmitter.cpp
@@ -2370,10 +2370,6 @@ void NeonEmitter::run(raw_ostream &OS) {
         "Please use -mfloat-abi=softfp or -mfloat-abi=hard\"\n";
   OS << "#else\n\n";
 
-  OS << "#if !defined(__ARM_NEON)\n";
-  OS << "#error \"NEON support not enabled\"\n";
-  OS << "#else\n\n";
-
   OS << "#include <stdint.h>\n\n";
 
   OS << "#include <arm_bf16.h>\n";
@@ -2450,7 +2446,6 @@ void NeonEmitter::run(raw_ostream &OS) {
   OS << "#undef __ai\n\n";
   OS << "#endif /* if !defined(__ARM_NEON) */\n";
   OS << "#endif /* ifndef __ARM_FP */\n";
-  OS << "#endif /* __ARM_NEON_H */\n";
 }
 
 /// run - Read the records in arm_fp16.td and output arm_fp16.h.  arm_fp16.h