[clang][SveEmitter] Fix enum declarations. [NFCI]

[fpetrogalli]

Summary

Adapt the declarations of svpattern and svprfop to the most recent
one defined in section "5. Enum declarations" of the SVE ACLE
specifications [1].

The signature of the intrinsics using these enums have been changed
accordingly.

A test has been added to make sure that svpattern and svprfop are
not typedefs.

[1] https://developer.arm.com/documentation/100987/latest, version
00bet6

[joechrisellis]

Thanks for the patch @fpetrogalli! One small comment from me, but not a blocker for me, so approved.

clang/test/Sema/aarch64-sve-enums.c

15–16

[nit] It would be good if you could add a small comment here explaining what this is doing. As far as I can tell, you're creating a typedef'd struct with the same identifier as the one defined in arm_sve.h, then checking that it does not overload enum svpattern defined in arm_sve.h?

[fpetrogalli]

Improve comment in test.

clang/test/Sema/aarch64-sve-enums.c

+// REQUIRES: aarch64-registered-target
+// RUN: %clang_cc1 %s -triple aarch64-none-linux-gnu -target-feature +sve -fallow-half-arguments-and-returns  -fsyntax-only -verify
+// expected-no-diagnostics
+
+// This test makes sure that the enum declarations in section "5. Enum
+// declarations" of the SVE ACLE [1] are not presented as typedefs in
+// `arm_sve.h`. It does so by creating a typedef'd struct with the
+// same identifier as the one defined in `arm_sve.h`, then checking that
+// it does not overload the enum defined in `arm_sve.h`.
+//
+// [1] https://developer.arm.com/documentation/100987/latest version 00bet6
+
+typedef struct { float f; } svpattern;
+typedef struct { float f; } svprfop;
+#include <arm_sve.h>
+enum svpattern a1 = SV_ALL;
+svpattern b1 = {1.0f};
+enum svprfop a2 = SV_PLDL1KEEP;
+svprfop b2 = {1.0f};

clang/utils/TableGen/SveEmitter.cpp

std::string SVEType::builtin_str() const {
   }
 
   assert(isScalableVector() && "Unsupported type");
   return "q" + utostr(getNumElements() * NumVectors) + S;
 }
 
 std::string SVEType::str() const {
   if (isPredicatePattern())
-    return "sv_pattern";
+    return "enum svpattern";
 
   if (isPrefetchOp())
-    return "sv_prfop";
+    return "enum svprfop";
 
   std::string S;
   if (Void)
     S += "void";
   else {
     if (isScalableVector())
       S += "sv";
     if (!Signed && !isFloatingPoint())
void SVEEmitter::createHeader(raw_ostream &OS) {
   OS << "typedef __SVBool_t  svbool_t;\n\n";
 
   OS << "#ifdef __ARM_FEATURE_SVE_BF16\n";
   OS << "typedef __clang_svbfloat16x2_t svbfloat16x2_t;\n";
   OS << "typedef __clang_svbfloat16x3_t svbfloat16x3_t;\n";
   OS << "typedef __clang_svbfloat16x4_t svbfloat16x4_t;\n";
   OS << "#endif\n";
 
-  OS << "typedef enum\n";
+  OS << "enum svpattern\n";
   OS << "{\n";
   OS << "  SV_POW2 = 0,\n";
   OS << "  SV_VL1 = 1,\n";
   OS << "  SV_VL2 = 2,\n";
   OS << "  SV_VL3 = 3,\n";
   OS << "  SV_VL4 = 4,\n";
   OS << "  SV_VL5 = 5,\n";
   OS << "  SV_VL6 = 6,\n";
   OS << "  SV_VL7 = 7,\n";
   OS << "  SV_VL8 = 8,\n";
   OS << "  SV_VL16 = 9,\n";
   OS << "  SV_VL32 = 10,\n";
   OS << "  SV_VL64 = 11,\n";
   OS << "  SV_VL128 = 12,\n";
   OS << "  SV_VL256 = 13,\n";
   OS << "  SV_MUL4 = 29,\n";
   OS << "  SV_MUL3 = 30,\n";
   OS << "  SV_ALL = 31\n";
-  OS << "} sv_pattern;\n\n";
+  OS << "};\n\n";
 
-  OS << "typedef enum\n";
+  OS << "enum svprfop\n";
   OS << "{\n";
   OS << "  SV_PLDL1KEEP = 0,\n";
   OS << "  SV_PLDL1STRM = 1,\n";
   OS << "  SV_PLDL2KEEP = 2,\n";
   OS << "  SV_PLDL2STRM = 3,\n";
   OS << "  SV_PLDL3KEEP = 4,\n";
   OS << "  SV_PLDL3STRM = 5,\n";
   OS << "  SV_PSTL1KEEP = 8,\n";
   OS << "  SV_PSTL1STRM = 9,\n";
   OS << "  SV_PSTL2KEEP = 10,\n";
   OS << "  SV_PSTL2STRM = 11,\n";
   OS << "  SV_PSTL3KEEP = 12,\n";
   OS << "  SV_PSTL3STRM = 13\n";
-  OS << "} sv_prfop;\n\n";
+  OS << "};\n\n";
 
   OS << "/* Function attributes */\n";
   OS << "#define __aio static inline __attribute__((__always_inline__, "
         "__nodebug__, __overloadable__))\n\n";
 
   // Add reinterpret functions.
   for (auto ShortForm : { false, true } )
     for (const ReinterpretTypeInfo &From : Reinterprets)