aarch64: Add initial support for -mcpu=zeus

This patch adds support for the Arm Zeus CPU.
Bootstrapped and tested on aarch64-none-linux-gnu.

gcc/

2020-06-02  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>

	* config/aarch64/aarch64-cores.def (zeus): Define.
	* config/aarch64/aarch64-tune.md: Regenerate.
	* doc/invoke.texi (AArch64 Options): Document zeus -mcpu option.

gcc/config/aarch64/aarch64-cores.def

@@ -129,6 +129,9 @@ AARCH64_CORE("thunderx3t110",  thunderx3t110,  thunderx3t110, 8_3A,  AARCH64_FL_
 
 /* ARMv8.4-A Architecture Processors.  */
 
+/* Arm ('A') cores.  */
+AARCH64_CORE("zeus", zeus, cortexa57, 8_4A,  AARCH64_FL_FOR_ARCH8_4 | AARCH64_FL_SVE | AARCH64_FL_RCPC | AARCH64_FL_I8MM | AARCH64_FL_BF16 | AARCH64_FL_F16 | AARCH64_FL_PROFILE | AARCH64_FL_SSBS | AARCH64_FL_RNG, neoversen1, 0x41, 0xd40, -1)
+
 /* Qualcomm ('Q') cores. */
 AARCH64_CORE("saphira",     saphira,    saphira,    8_4A,  AARCH64_FL_FOR_ARCH8_4 | AARCH64_FL_CRYPTO | AARCH64_FL_RCPC, saphira,   0x51, 0xC01, -1)
 

gcc/config/aarch64/aarch64-tune.md

 ;; -*- buffer-read-only: t -*-
 ;; Generated automatically by gentune.sh from aarch64-cores.def
 (define_attr "tune"
-	"cortexa34,cortexa35,cortexa53,cortexa57,cortexa72,cortexa73,thunderx,thunderxt88p1,thunderxt88,octeontx,octeontxt81,octeontxt83,thunderxt81,thunderxt83,emag,xgene1,falkor,qdf24xx,exynosm1,phecda,thunderx2t99p1,vulcan,thunderx2t99,cortexa55,cortexa75,cortexa76,cortexa76ae,cortexa77,cortexa65,cortexa65ae,ares,neoversen1,neoversee1,octeontx2,octeontx2t98,octeontx2t96,octeontx2t93,octeontx2f95,octeontx2f95n,octeontx2f95mm,tsv110,thunderx3t110,saphira,cortexa57cortexa53,cortexa72cortexa53,cortexa73cortexa35,cortexa73cortexa53,cortexa75cortexa55,cortexa76cortexa55"
+	"cortexa34,cortexa35,cortexa53,cortexa57,cortexa72,cortexa73,thunderx,thunderxt88p1,thunderxt88,octeontx,octeontxt81,octeontxt83,thunderxt81,thunderxt83,emag,xgene1,falkor,qdf24xx,exynosm1,phecda,thunderx2t99p1,vulcan,thunderx2t99,cortexa55,cortexa75,cortexa76,cortexa76ae,cortexa77,cortexa65,cortexa65ae,ares,neoversen1,neoversee1,octeontx2,octeontx2t98,octeontx2t96,octeontx2t93,octeontx2f95,octeontx2f95n,octeontx2f95mm,tsv110,thunderx3t110,zeus,saphira,cortexa57cortexa53,cortexa72cortexa53,cortexa73cortexa35,cortexa73cortexa53,cortexa75cortexa55,cortexa76cortexa55"
 	(const (symbol_ref "((enum attr_tune) aarch64_tune)")))

gcc/doc/invoke.texi

@@ -16978,7 +16978,7 @@ performance of the code.  Permissible values for this option are:
 @samp{octeontx2f95mm}
 @samp{thunderx}, @samp{thunderxt88},
 @samp{thunderxt88p1}, @samp{thunderxt81}, @samp{tsv110},
-@samp{thunderxt83}, @samp{thunderx2t99}, @samp{thunderx3t110},
+@samp{thunderxt83}, @samp{thunderx2t99}, @samp{thunderx3t110}, @samp{zeus},
 @samp{cortex-a57.cortex-a53}, @samp{cortex-a72.cortex-a53},
 @samp{cortex-a73.cortex-a35}, @samp{cortex-a73.cortex-a53},
 @samp{cortex-a75.cortex-a55}, @samp{cortex-a76.cortex-a55}