[ARM64EC] Add arm64ec for getArchName

[bcl5980]

Summary

Followup D125412, return the correct arch name for Arm64EC

[mstorsjo]

LGTM

Is there any testcase that could be added (e.g. for unittests for the Triple class) where this change makes a difference?

[bcl5980]

add test

[bcl5980]

correct test

[mstorsjo]

LGTM, thanks! This test does indeed now test what I'd expect for this change.

llvm/lib/Support/Triple.cpp

StringRef Triple::getArchName(ArchType Kind, SubArchType SubArch) const {
   case Triple::mips64:
     if (SubArch == MipsSubArch_r6)
       return "mipsisa64r6";
     break;
   case Triple::mips64el:
     if (SubArch == MipsSubArch_r6)
       return "mipsisa64r6el";
     break;
+  case Triple::aarch64:
+    if (SubArch == AArch64SubArch_arm64ec)
+      return "arm64ec";
+    break;
   default:
     break;
   }
   return getArchTypeName(Kind);
 }
 
 StringRef Triple::getVendorName() const {
   StringRef Tmp = StringRef(Data).split('-').second; // Strip first component

llvm/unittests/ADT/TripleTest.cpp

// AARCH64
     Triple T = Triple("aarch64_be");
     EXPECT_EQ(Triple::aarch64_be, T.getArch());
   }
   {
     Triple T = Triple("arm64e");
     EXPECT_EQ(Triple::aarch64, T.getArch());
     EXPECT_EQ(Triple::AArch64SubArch_arm64e, T.getSubArch());
   }
+  {
+    Triple T = Triple("arm64ec");
+    EXPECT_EQ(Triple::aarch64, T.getArch());
+    EXPECT_EQ(Triple::AArch64SubArch_arm64ec, T.getSubArch());
+  }
+  {
+    Triple T;
+    T.setArch(Triple::aarch64, Triple::AArch64SubArch_arm64ec);
+    EXPECT_EQ("arm64ec", T.getArchName());
+  }
 }
 
 TEST(TripleTest, isArmT32) {
   // Not isArmT32
   {
     Triple T = Triple("thumbv6m");
     EXPECT_FALSE(T.isArmT32());
   }