[RISCV] Add ESWIN EIC770X (SiFive P550) to getHostCPUNameForRISCV. (#125277)

This enables -mcpu=native for the HiFive Premier P550 board.

Author: topperc

llvm/lib/TargetParser/Host.cpp

@@ -493,6 +493,7 @@ StringRef sys::detail::getHostCPUNameForRISCV(StringRef ProcCpuinfoContent) {
   }
 
   return StringSwitch<const char *>(UArch)
+      .Case("eswin,eic770x", "sifive-p550")
       .Case("sifive,u74-mc", "sifive-u74")
       .Case("sifive,bullet0", "sifive-u74")
       .Default("");

llvm/unittests/TargetParser/Host.cpp

@@ -405,6 +405,19 @@ uarch           : sifive,u74-mc
   EXPECT_EQ(
       sys::detail::getHostCPUNameForRISCV("uarch           : sifive,bullet0\n"),
       "sifive-u74");
+
+  const StringRef SifiveP550MCProcCPUInfo = R"(
+processor       : 0
+hart            : 2
+isa             : rv64imafdch_zicsr_zifencei_zba_zbb_sscofpmf
+mmu             : sv48
+uarch           : eswin,eic770x
+)";
+  EXPECT_EQ(sys::detail::getHostCPUNameForRISCV(SifiveP550MCProcCPUInfo),
+            "sifive-p550");
+  EXPECT_EQ(
+      sys::detail::getHostCPUNameForRISCV("uarch           : eswin,eic770x\n"),
+      "sifive-p550");
 }
 
 static bool runAndGetCommandOutput(