[PATCH] AArch64: Add support for __builtin_roundeven[f] [PR100966]

[Wilco Dijkstra]

Enable __builtin_roundeven[f] by adding roundeven as an alias to the
existing frintn support.

Bootstrap OK and passes regress.

ChangeLog:
2021-06-18  Wilco Dijkstra  <wdijkstr@arm.com>

        PR target/100966
        * config/aarch64/aarch64.md (UNSPEC_FRINTR): Add.
        * config/aarch64/aarch64.c (aarch64_frint_unspec_p): Add UNSPEC_FRINTR.
        (aarch64_rtx_cost): Likewise.
        * config/aarch64/iterators.md (FRINT): Add UNSPEC_FRINTR.
        (frint_pattern): Likewise.
        (frint_suffix): Likewise.

gcc/testsuite
        PR target/100966
        * gcc.target/aarch64/frint.x: Add roundeven tests.	
        * gcc.target/aarch64/frint_double.c: Likewise.
        * gcc.target/aarch64/frint_float.c: Likewise.

---

diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index f4d264bbc817153b330bac9ab423bf561689ebf2..63bd49d475433c04faa89bb380a9d17e4ad4bc6c 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -12253,6 +12253,7 @@ aarch64_frint_unspec_p (unsigned int u)
       case UNSPEC_FRINTM:
       case UNSPEC_FRINTA:
       case UNSPEC_FRINTN:
+      case UNSPEC_FRINTR:
       case UNSPEC_FRINTX:
       case UNSPEC_FRINTI:
         return true;
@@ -13648,6 +13649,7 @@ cost_plus:
               || uns_code == UNSPEC_FRINTM
               || uns_code == UNSPEC_FRINTN
               || uns_code == UNSPEC_FRINTP
+	      || uns_code == UNSPEC_FRINTR
               || uns_code == UNSPEC_FRINTZ)
             x = XVECEXP (x, 0, 0);
         }
diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index 30effca6f3562f6870a6cc8097750e63bb0d424d..70e46f28259640a273d444a2b963246ed9a91109 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -167,6 +167,7 @@ (define_c_enum "unspec" [
     UNSPEC_FRINTM
     UNSPEC_FRINTN
     UNSPEC_FRINTP
+    UNSPEC_FRINTR
     UNSPEC_FRINTX
     UNSPEC_FRINTZ
     UNSPEC_GOTSMALLPIC
diff --git a/gcc/config/aarch64/iterators.md b/gcc/config/aarch64/iterators.md
index cac33ae812b382cd55611b0da8a6e9eac3a513c4..1542661c6d101ed53c6e1c8683cbca32baefebbd 100644
--- a/gcc/config/aarch64/iterators.md
+++ b/gcc/config/aarch64/iterators.md
@@ -2291,7 +2291,7 @@ (define_int_iterator REVERSE [UNSPEC_REV64 UNSPEC_REV32 UNSPEC_REV16])
 
 (define_int_iterator FRINT [UNSPEC_FRINTZ UNSPEC_FRINTP UNSPEC_FRINTM
 			     UNSPEC_FRINTN UNSPEC_FRINTI UNSPEC_FRINTX
-			     UNSPEC_FRINTA])
+			     UNSPEC_FRINTA UNSPEC_FRINTR ])
 
 (define_int_iterator FCVT [UNSPEC_FRINTZ UNSPEC_FRINTP UNSPEC_FRINTM
 			    UNSPEC_FRINTA UNSPEC_FRINTN])
@@ -3079,13 +3079,14 @@ (define_int_attr frint_pattern [(UNSPEC_FRINTZ "btrunc")
 				(UNSPEC_FRINTI "nearbyint")
 				(UNSPEC_FRINTX "rint")
 				(UNSPEC_FRINTA "round")
-				(UNSPEC_FRINTN "frintn")])
+				(UNSPEC_FRINTN "frintn")
+				(UNSPEC_FRINTR "roundeven")])
 
 ;; frint suffix for floating-point rounding instructions.
 (define_int_attr frint_suffix [(UNSPEC_FRINTZ "z") (UNSPEC_FRINTP "p")
 			       (UNSPEC_FRINTM "m") (UNSPEC_FRINTI "i")
 			       (UNSPEC_FRINTX "x") (UNSPEC_FRINTA "a")
-			       (UNSPEC_FRINTN "n")])
+			       (UNSPEC_FRINTN "n") (UNSPEC_FRINTR "n")])
 
 (define_int_attr fcvt_pattern [(UNSPEC_FRINTZ "btrunc") (UNSPEC_FRINTA "round")
 			       (UNSPEC_FRINTP "ceil") (UNSPEC_FRINTM "floor")
diff --git a/gcc/testsuite/gcc.target/aarch64/frint.x b/gcc/testsuite/gcc.target/aarch64/frint.x
index 1403740686ea3927d2c39eb2466ef8cc67e223b2..d598a25ff21b8feeca6a96de79848b2fbde7f31e 100644
--- a/gcc/testsuite/gcc.target/aarch64/frint.x
+++ b/gcc/testsuite/gcc.target/aarch64/frint.x
@@ -4,6 +4,7 @@ extern GPF SUFFIX(floor) (GPF);
 extern GPF SUFFIX(nearbyint) (GPF);
 extern GPF SUFFIX(rint) (GPF);
 extern GPF SUFFIX(round) (GPF);
+extern GPF SUFFIX(roundeven) (GPF);
 
 GPF test1a (GPF x)
 {
@@ -64,3 +65,14 @@ GPF test6b (GPF x)
 {
   return SUFFIX(round)(x);
 }
+
+GPF test7a (GPF x)
+{
+  return SUFFIX(__builtin_roundeven)(x);
+}
+
+GPF test7b (GPF x)
+{
+  return SUFFIX(roundeven)(x);
+}
+
diff --git a/gcc/testsuite/gcc.target/aarch64/frint_double.c b/gcc/testsuite/gcc.target/aarch64/frint_double.c
index 96139496ca454cebd41d31e8b018dab7ffa33a3f..1d28eb09e11842802ab632a7696de4407263f8ce 100644
--- a/gcc/testsuite/gcc.target/aarch64/frint_double.c
+++ b/gcc/testsuite/gcc.target/aarch64/frint_double.c
@@ -12,3 +12,4 @@
 /* { dg-final { scan-assembler-times "frinti\td\[0-9\]" 2 } } */
 /* { dg-final { scan-assembler-times "frintx\td\[0-9\]" 2 } } */
 /* { dg-final { scan-assembler-times "frinta\td\[0-9\]" 2 } } */
+/* { dg-final { scan-assembler-times "frintn\td\[0-9\]" 2 } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/frint_float.c b/gcc/testsuite/gcc.target/aarch64/frint_float.c
index 493ec37f940a6e8cb01ea7e324073fa22099636c..530cf975db3d52c30bce43d0c40229b2b375cdea 100644
--- a/gcc/testsuite/gcc.target/aarch64/frint_float.c
+++ b/gcc/testsuite/gcc.target/aarch64/frint_float.c
@@ -12,3 +12,4 @@
 /* { dg-final { scan-assembler-times "frinti\ts\[0-9\]" 2 } } */
 /* { dg-final { scan-assembler-times "frintx\ts\[0-9\]" 2 } } */
 /* { dg-final { scan-assembler-times "frinta\ts\[0-9\]" 2 } } */
+/* { dg-final { scan-assembler-times "frintn\ts\[0-9\]" 2 } } */