[Backport][SME] aarch64: Define __ARM_FEATURE_RCPC

Reference: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=c1b0a767f04a8ccbaff2a7b71d5c817cdb469630

ARM-software/acle#199 adds a new feature
macro for RCPC, for use in things like inline assembly.  This patch
adds the associated support to GCC.

Also, RCPC is required for Armv8.3-A and later, but the armv8.3-a
entry didn't include it.  This was probably harmless in practice
since GCC simply ignored the extension until now.  (The GAS
definition is OK.)

gcc/
	* config/aarch64/aarch64.h (AARCH64_ISA_RCPC): New macro.
	* config/aarch64/aarch64-arches.def (armv8.3-a): Include RCPC.
	* config/aarch64/aarch64-cores.def (thunderx3t110, zeus, neoverse-v1)
	(neoverse-512tvb, saphira): Remove RCPC from these Armv8.3-A+ cores.
	* config/aarch64/aarch64-c.cc (aarch64_update_cpp_builtins): Define
	__ARM_FEATURE_RCPC when appropriate.

gcc/testsuite/
	* gcc.target/aarch64/pragma_cpp_predefs_1.c: Add RCPC tests.

gcc/config/aarch64/aarch64-arches.def

@@ -33,7 +33,7 @@
 AARCH64_ARCH("armv8-a",       generic,       V8A,       8,  (SIMD))
 AARCH64_ARCH("armv8.1-a",     generic,       V8_1A,     8,  (V8A, LSE, CRC, RDMA))
 AARCH64_ARCH("armv8.2-a",     generic,       V8_2A,     8,  (V8_1A))
-AARCH64_ARCH("armv8.3-a",     generic,       V8_3A,     8,  (V8_2A, PAUTH))
+AARCH64_ARCH("armv8.3-a",     generic,       V8_3A,     8,  (V8_2A, PAUTH, RCPC))
 AARCH64_ARCH("armv8.4-a",     generic,       V8_4A,     8,  (V8_3A, F16FML, DOTPROD, FLAGM))
 AARCH64_ARCH("armv8.5-a",     generic,       V8_5A,     8,  (V8_4A, SB, SSBS, PREDRES))
 AARCH64_ARCH("armv8.6-a",     generic,       V8_6A,     8,  (V8_5A, I8MM, BF16))

gcc/config/aarch64/aarch64-c.cc

@@ -202,6 +202,7 @@ aarch64_update_cpp_builtins (cpp_reader *pfile)
 			"__ARM_FEATURE_BF16_SCALAR_ARITHMETIC", pfile);
   aarch64_def_or_undef (TARGET_LS64,
 			"__ARM_FEATURE_LS64", pfile);
+  aarch64_def_or_undef (AARCH64_ISA_RCPC, "__ARM_FEATURE_RCPC", pfile);
 
   /* Not for ACLE, but required to keep "float.h" correct if we switch
      target between implementations that do or do not support ARMv8.2-A

gcc/config/aarch64/aarch64-cores.def

@@ -133,17 +133,17 @@ AARCH64_CORE("tsv110",  tsv110, tsv110, V8_2A,  (CRYPTO, F16), tsv110,   0x48, 0
 /* ARMv8.3-A Architecture Processors.  */
 
 /* Marvell cores (TX3). */
-AARCH64_CORE("thunderx3t110",  thunderx3t110,  thunderx3t110, V8_3A,  (CRYPTO, RCPC, SM4, SHA3, F16FML), thunderx3t110, 0x43, 0x0b8, 0x0a)
+AARCH64_CORE("thunderx3t110",  thunderx3t110,  thunderx3t110, V8_3A,  (CRYPTO, SM4, SHA3, F16FML), thunderx3t110, 0x43, 0x0b8, 0x0a)
 
 /* ARMv8.4-A Architecture Processors.  */
 
 /* Arm ('A') cores.  */
-AARCH64_CORE("zeus", zeus, cortexa57, V8_4A,  (SVE, RCPC, I8MM, BF16, PROFILE, SSBS, RNG), neoversev1, 0x41, 0xd40, -1)
-AARCH64_CORE("neoverse-v1", neoversev1, cortexa57, V8_4A,  (SVE, RCPC, I8MM, BF16, PROFILE, SSBS, RNG), neoversev1, 0x41, 0xd40, -1)
-AARCH64_CORE("neoverse-512tvb", neoverse512tvb, cortexa57, V8_4A,  (SVE, RCPC, I8MM, BF16, PROFILE, SSBS, RNG), neoverse512tvb, INVALID_IMP, INVALID_CORE, -1)
+AARCH64_CORE("zeus", zeus, cortexa57, V8_4A,  (SVE, I8MM, BF16, PROFILE, SSBS, RNG), neoversev1, 0x41, 0xd40, -1)
+AARCH64_CORE("neoverse-v1", neoversev1, cortexa57, V8_4A,  (SVE, I8MM, BF16, PROFILE, SSBS, RNG), neoversev1, 0x41, 0xd40, -1)
+AARCH64_CORE("neoverse-512tvb", neoverse512tvb, cortexa57, V8_4A,  (SVE, I8MM, BF16, PROFILE, SSBS, RNG), neoverse512tvb, INVALID_IMP, INVALID_CORE, -1)
 
 /* Qualcomm ('Q') cores. */
-AARCH64_CORE("saphira",     saphira,    saphira,    V8_4A,  (CRYPTO, RCPC), saphira,   0x51, 0xC01, -1)
+AARCH64_CORE("saphira",     saphira,    saphira,    V8_4A,  (CRYPTO), saphira,   0x51, 0xC01, -1)
 
 /* ARMv8-A big.LITTLE implementations.  */
 

gcc/config/aarch64/aarch64.h

@@ -201,6 +201,7 @@ enum class aarch64_feature : unsigned char {
 #define AARCH64_ISA_SM4	           (aarch64_isa_flags & AARCH64_FL_SM4)
 #define AARCH64_ISA_SHA3	   (aarch64_isa_flags & AARCH64_FL_SHA3)
 #define AARCH64_ISA_F16FML	   (aarch64_isa_flags & AARCH64_FL_F16FML)
+#define AARCH64_ISA_RCPC	   (aarch64_isa_flags & AARCH64_FL_RCPC)
 #define AARCH64_ISA_RCPC8_4	   (aarch64_isa_flags & AARCH64_FL_V8_4A)
 #define AARCH64_ISA_RNG		   (aarch64_isa_flags & AARCH64_FL_RNG)
 #define AARCH64_ISA_V8_5A	   (aarch64_isa_flags & AARCH64_FL_V8_5A)

gcc/testsuite/gcc.target/aarch64/pragma_cpp_predefs_1.c

@@ -248,6 +248,26 @@
 #error "__ARM_FEATURE_CRC32 is not defined but should be!"
 #endif
 
+#pragma GCC target ("arch=armv8.2-a")
+#ifdef __ARM_FEATURE_RCPC
+#error "__ARM_FEATURE_RCPC is defined but should not be!"
+#endif
+
+#pragma GCC target ("arch=armv8.2-a+rcpc")
+#ifndef __ARM_FEATURE_RCPC
+#error "__ARM_FEATURE_RCPC is not defined but should be!"
+#endif
+
+#pragma GCC target ("+norcpc")
+#ifdef __ARM_FEATURE_RCPC
+#error "__ARM_FEATURE_RCPC is defined but should not be!"
+#endif
+
+#pragma GCC target ("arch=armv8.3-a")
+#ifndef __ARM_FEATURE_RCPC
+#error "__ARM_FEATURE_RCPC is not defined but should be!"
+#endif
+
 int
 foo (int a)
 {