S/390: PR69709 Fix risbg splitter

This fixes a wrong code generation problem with the splitters introduced
with that patch: https://gcc.gnu.org/ml/gcc-patches/2015-07/msg01840.html

The target operand is used as temporary.  This fails if it matches the
source of the left shift which is read after writing the temporary.

Thanks to Dominik for debugging it and thanks to Richard for the fix!

Bootstrapped and regtested on s390x with-arch=z13.

Bye,

-Andreas-

gcc/ChangeLog:

2016-02-26  Richard Henderson  <rth@redhat.com>

	PR target/69709
	* config/s390/s390.md (risbg and risbgn splitters): Allocate new
	pseudo in case the target rtx matches the source of the left
	shift.

gcc/testsuite/ChangeLog:

2016-02-26  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	PR target/69709
	* gcc.target/s390/pr69709.c: New test.

From-SVN: r233752

4 files changed, 71 insertions, 4 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6550115..2668f2e 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2016-02-26  Richard Henderson  <rth@redhat.com>
+
+	PR target/69709
+	* config/s390/s390.md (risbg and risbgn splitters): Allocate new
+	pseudo in case the target rtx matches the source of the left
+	shift.
+
 2016-02-26  Martin Jambor  <mjambor@suse.cz>
 
 	PR hsa/69568
diff --git a/gcc/config/s390/s390.md b/gcc/config/s390/s390.md
index 2c90eae..8f92018 100644
--- a/gcc/config/s390/s390.md
+++ b/gcc/config/s390/s390.md
@@ -3876,13 +3876,21 @@
 		 (ashift:GPR (match_operand:GPR 3 "nonimmediate_operand" "")
 			     (match_operand:GPR 4 "nonzero_shift_count_operand" ""))))]
   "TARGET_ZEC12 && UINTVAL (operands[2]) + UINTVAL (operands[4]) >= <bitsize>"
-  [(set (match_dup 0)
+  [(set (match_dup 6)
 	(lshiftrt:GPR (match_dup 1) (match_dup 2)))
    (set (match_dup 0)
-	(ior:GPR (and:GPR (match_dup 0) (match_dup 5))
+	(ior:GPR (and:GPR (match_dup 6) (match_dup 5))
 		 (ashift:GPR (match_dup 3) (match_dup 4))))]
 {
   operands[5] = GEN_INT ((1UL << UINTVAL (operands[4])) - 1);
+  if (rtx_equal_p (operands[0], operands[3]))
+    {
+      if (!can_create_pseudo_p ())
+	FAIL;
+      operands[6] = gen_reg_rtx (<MODE>mode);
+    }
+  else
+    operands[6] = operands[0];
 })
 
 (define_split
@@ -3894,15 +3902,23 @@
 			       (match_operand:GPR 4 "nonzero_shift_count_operand" ""))))
      (clobber (reg:CC CC_REGNUM))])]
   "TARGET_Z10 && !TARGET_ZEC12 && UINTVAL (operands[2]) + UINTVAL (operands[4]) >= <bitsize>"
-  [(set (match_dup 0)
+  [(set (match_dup 6)
 	(lshiftrt:GPR (match_dup 1) (match_dup 2)))
    (parallel
     [(set (match_dup 0)
-	  (ior:GPR (and:GPR (match_dup 0) (match_dup 5))
+	  (ior:GPR (and:GPR (match_dup 6) (match_dup 5))
 		   (ashift:GPR (match_dup 3) (match_dup 4))))
      (clobber (reg:CC CC_REGNUM))])]
 {
   operands[5] = GEN_INT ((1UL << UINTVAL (operands[4])) - 1);
+  if (rtx_equal_p (operands[0], operands[3]))
+    {
+      if (!can_create_pseudo_p ())
+	FAIL;
+      operands[6] = gen_reg_rtx (<MODE>mode);
+    }
+  else
+    operands[6] = operands[0];
 })
 
 (define_insn "*r<noxa>sbg_<mode>_noshift"
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 99e0f2f..a70a069 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2016-02-26  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
+
+	PR target/69709
+	* gcc.target/s390/pr69709.c: New test.
+
 2016-02-26  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	PR target/69245
diff --git a/gcc/testsuite/gcc.target/s390/pr69709.c b/gcc/testsuite/gcc.target/s390/pr69709.c
new file mode 100644
index 0000000..e9aa024
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/pr69709.c
@@ -0,0 +1,39 @@
+/* PR69709 This testcase used to fail due to a broken risbg
+   splitter.  */
+
+/* { dg-do run } */
+/* { dg-options "-O3 -march=z10" } */
+
+
+typedef struct
+{
+  unsigned int sig[2];
+}
+val_t;
+
+unsigned int __attribute__ ((noinline))
+div_significands (const val_t * a)
+{
+  val_t u = *a;
+  int bit = 64;
+  unsigned int r;
+  do
+    {
+      u.sig[1] = (u.sig[1] << 1) | (u.sig[0] >> 31);
+      u.sig[0] = 42;
+
+      if (bit == 64)
+	r = u.sig[1];
+    }
+  while (--bit >= 0);
+  return r;
+}
+
+int
+main (void)
+{
+  val_t a = { { 0x1, 0x1 } };
+  if (div_significands (&a) != 2)
+    __builtin_abort ();
+  return 0;
+}