[SYCL] Allow neon attributes for ARM host

[hvdijk]

We permit neon attributes in CUDA device code, but this permission was only for CUDA device code. The same permission makes sense for SYCL device code as well, especially now that neon attributes are used in glibc headers.

[llvmbot]

@llvm/pr-subscribers-clang

Author: Harald van Dijk (hvdijk)

Changes

We permit neon attributes in CUDA device code, but this permission was only for CUDA device code. The same permission makes sense for SYCL device code as well, especially now that neon attributes are used in glibc headers.

---

Full diff: https://github.com/llvm/llvm-project/pull/94229.diff

2 Files Affected:

• (modified) clang/lib/Sema/SemaType.cpp (+6-6)
• (added) clang/test/SemaSYCL/neon-attrs.cpp (+16)

diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 7cec82c701028..a8a1463522d03 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -8077,10 +8077,10 @@ static bool verifyValidIntegerConstantExpr(Sema &S, const ParsedAttr &Attr,
 /// match one of the standard Neon vector types.
 static void HandleNeonVectorTypeAttr(QualType &CurType, const ParsedAttr &Attr,
                                      Sema &S, VectorKind VecKind) {
-  bool IsTargetCUDAAndHostARM = false;
-  if (S.getLangOpts().CUDAIsDevice) {
+  bool IsTargetDeviceAndHostARM = false;
+  if (S.getLangOpts().CUDAIsDevice || S.getLangOpts().SYCLIsDevice) {
     const TargetInfo *AuxTI = S.getASTContext().getAuxTargetInfo();
-    IsTargetCUDAAndHostARM =
+    IsTargetDeviceAndHostARM =
         AuxTI && (AuxTI->getTriple().isAArch64() || AuxTI->getTriple().isARM());
   }
 
@@ -8090,7 +8090,7 @@ static void HandleNeonVectorTypeAttr(QualType &CurType, const ParsedAttr &Attr,
         S.Context.getTargetInfo().hasFeature("mve") ||
         S.Context.getTargetInfo().hasFeature("sve") ||
         S.Context.getTargetInfo().hasFeature("sme") ||
-        IsTargetCUDAAndHostARM) &&
+        IsTargetDeviceAndHostARM) &&
       VecKind == VectorKind::Neon) {
     S.Diag(Attr.getLoc(), diag::err_attribute_unsupported)
         << Attr << "'neon', 'mve', 'sve' or 'sme'";
@@ -8099,7 +8099,7 @@ static void HandleNeonVectorTypeAttr(QualType &CurType, const ParsedAttr &Attr,
   }
   if (!(S.Context.getTargetInfo().hasFeature("neon") ||
         S.Context.getTargetInfo().hasFeature("mve") ||
-        IsTargetCUDAAndHostARM) &&
+        IsTargetDeviceAndHostARM) &&
       VecKind == VectorKind::NeonPoly) {
     S.Diag(Attr.getLoc(), diag::err_attribute_unsupported)
         << Attr << "'neon' or 'mve'";
@@ -8121,7 +8121,7 @@ static void HandleNeonVectorTypeAttr(QualType &CurType, const ParsedAttr &Attr,
 
   // Only certain element types are supported for Neon vectors.
   if (!isPermittedNeonBaseType(CurType, VecKind, S) &&
-      !IsTargetCUDAAndHostARM) {
+      !IsTargetDeviceAndHostARM) {
     S.Diag(Attr.getLoc(), diag::err_attribute_invalid_vector_type) << CurType;
     Attr.setInvalid();
     return;
diff --git a/clang/test/SemaSYCL/neon-attrs.cpp b/clang/test/SemaSYCL/neon-attrs.cpp
new file mode 100644
index 0000000000000..ec79fa5033308
--- /dev/null
+++ b/clang/test/SemaSYCL/neon-attrs.cpp
@@ -0,0 +1,16 @@
+// Host compilation on ARM with neon enabled (no errors expected).
+// RUN: %clang_cc1 -triple aarch64-linux-gnu -target-feature +neon -fsyntax-only -verify=quiet %s
+
+// Host compilation on ARM with neon disabled.
+// RUN: %clang_cc1 -triple aarch64-linux-gnu -target-feature -neon -fsyntax-only -verify %s
+
+// Device compilation on ARM (no errors expected).
+// RUN: %clang_cc1 -triple spirv64 -aux-triple aarch64-linux-gnu -fsycl-is-device -fsyntax-only -verify=quiet %s
+
+// quiet-no-diagnostics
+typedef __attribute__((neon_vector_type(4))) float float32x4_t;
+// expected-error@-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@-1 {{'neon_polyvector_type' attribute is not supported on targets missing 'neon' or 'mve'}}

[hvdijk]

Rebased to address a conflict with changes that have gone in since I first submitted this, the PR remains otherwise identical and waiting to be reviewed.

[hvdijk]

The rebase apparently conflicted with #95224. In the test I added, I checked that I preserved the existing behaviour with -target-feature -neon, but that behaviour has since changed. Updated to remove that bit of the test.