[PATCH] S/390: Implement SD<->TD conversions

[Andreas Krebbel]

Hi,

on S/390 we have DFP conversions for SD<->DD and DD<->TD but miss
SD<->TD. The attached patch expands the missing patterns to SD->DD->TD
and TD->DD->SD to avoid library calls being emitted.

No regressions on s390 and s390x.

Bye,

-Andreas-

2014-09-10  Andreas Krebbel  <Andreas.Krebbel@de.ibm.com>

	* config/s390/s390.md ("trunctdsd2", "extendsdtd2"): New
	expanders.

2014-09-10  Andreas Krebbel  <Andreas.Krebbel@de.ibm.com>

	* gcc.target/s390/dfp-conv1.c: New testcase.

diff --git a/gcc/config/s390/s390.md b/gcc/config/s390/s390.md
index bcfe8f9..73ac0dc 100644
--- a/gcc/config/s390/s390.md
+++ b/gcc/config/s390/s390.md
@@ -4406,6 +4406,18 @@
   [(set_attr "op_type" "RRF")
    (set_attr "type"    "ftruncsd")])
 
+(define_expand "trunctdsd2"
+  [(parallel
+    [(set (match_dup 3)
+	  (float_truncate:DD (match_operand:TD 1 "register_operand" "")))
+     (clobber (match_scratch:TD 2 ""))])
+   (set (match_operand:SD 0 "register_operand" "")
+	(float_truncate:SD (match_dup 3)))]
+  "TARGET_HARD_DFP"
+{
+  operands[3] = gen_reg_rtx (DDmode);
+})
+
 ;
 ; extend(sf|df)(df|tf)2 instruction pattern(s).
 ;
@@ -4442,6 +4454,16 @@
   [(set_attr "op_type" "RRF")
    (set_attr "type"    "fsimptf")])
 
+(define_expand "extendsdtd2"
+  [(set (match_dup 2)
+	(float_extend:DD (match_operand:SD 1 "register_operand" "")))
+   (set (match_operand:TD 0 "register_operand" "")
+	(float_extend:TD (match_dup 2)))]
+  "TARGET_HARD_DFP"
+{
+  operands[2] = gen_reg_rtx (DDmode);
+})
+
 ; Binary Floating Point - load fp integer
 
 ; Expanders for: floor, btrunc, round, ceil, and nearbyint
diff --git a/gcc/testsuite/gcc.target/s390/dfp-conv1.c b/gcc/testsuite/gcc.target/s390/dfp-conv1.c
new file mode 100644
index 0000000..3c553a3
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/dfp-conv1.c
@@ -0,0 +1,22 @@
+/* We do not have hardware instructions which do a direct conversion
+   between the 32 and 128 bit DFP types.  But we can easily do it in
+   two steps.  Older libdfp implementations require this not to call
+   into a lib in order to prevent an endless loop.  */
+
+/* { dg-do compile } */
+/* { dg-options "-O3 -march=z10 -mzarch" } */
+
+_Decimal32 
+foo (_Decimal128 a)
+{
+  return (_Decimal32)a;
+}
+
+_Decimal128
+bar (_Decimal32 a)
+{
+  return (_Decimal128)a;
+}
+
+/* Make sure no library call is emitted.  */
+/* { dg-final { scan-assembler-not "brasl" } } */
-- 
1.7.11.4