[cse] Add support for string_literal.

Swift SVN r10824

Author: gottesmm

lib/SILPasses/CSE.cpp

@@ -62,6 +62,7 @@ namespace {
       case ValueKind::GlobalAddrInst:
       case ValueKind::IntegerLiteralInst:
       case ValueKind::FloatLiteralInst:
+      case ValueKind::StringLiteralInst:
         return true;
       default:
         return false;
@@ -114,6 +115,11 @@ unsigned llvm::DenseMapInfo<SimpleValue>::getHashValue(SimpleValue Val) {
                               X->getType(),
                               X->getBits());
   }
+  case ValueKind::StringLiteralInst: {
+    auto *X = cast<StringLiteralInst>(Inst);
+    return llvm::hash_combine(unsigned(ValueKind::StringLiteralInst),
+                              X->getValue());
+  }
   default:
     llvm_unreachable("Unhandled ValueKind.");
   }

test/SILPasses/cse.sil

@@ -482,3 +482,20 @@ sil @floatliteral : $@thin () -> (Builtin.FPIEEE32) {
   %4 = apply %2(%0, %1) : $@thin (Builtin.FPIEEE32, Builtin.FPIEEE32) -> Builtin.FPIEEE32 // user: %6
   return %4 : $(Builtin.FPIEEE32)
 }
+
+sil @string_use : $@thin (Builtin.RawPointer, Builtin.Int64, Builtin.Int1, String.metatype, Builtin.RawPointer, Builtin.Int64, Builtin.Int1, String.metatype) -> ()
+
+
+// CHECK-LABEL: stringliteral
+// CHECK: [[TARGET:%[0-9]+]] = string_literal "First"
+// CHECK-NOT: string_literal "First"
+// CHECK: apply {{%[0-9]+}}([[TARGET]]#0, [[TARGET]]#1, [[TARGET]]#2, {{%[0-9]+}}, [[TARGET]]#0, [[TARGET]]#1, [[TARGET]]#2, {{%[0-9]+}})
+sil @stringliteral : $@thin () -> () {
+  %0 = string_literal "First"
+  %1 = string_literal "First"
+  %2 = metatype $String.metatype
+  %3 = function_ref @string_use : $@thin (Builtin.RawPointer, Builtin.Int64, Builtin.Int1, String.metatype, Builtin.RawPointer, Builtin.Int64, Builtin.Int1, String.metatype) -> ()
+  apply %3 (%0#0, %0#1, %0#2, %2, %1#0, %1#1, %1#2, %2): $@thin (Builtin.RawPointer, Builtin.Int64, Builtin.Int1, String.metatype, Builtin.RawPointer, Builtin.Int64, Builtin.Int1, String.metatype) -> ()
+  %4 = tuple()
+  return %4 : $()
+}