2014-09-03 Andreas Krebbel <Andreas.Krebbel@de.ibm.com>

	PR target/61078
	* config/s390/s390.md ("*negdi2_31"): Add s390_split_ok_p check
	and add a second splitter to handle the remaining cases.

2014-09-03  Andreas Krebbel  <Andreas.Krebbel@de.ibm.com>

	PR target/61078
	* gcc.target/s390/pr61078.c: New testcase.




git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@214850 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 51 insertions, 3 deletions

diff --git a/gcc/config/s390/s390.md b/gcc/config/s390/s390.md
index dde529cc684..bcfe8f94f7a 100644
--- a/gcc/config/s390/s390.md
+++ b/gcc/config/s390/s390.md
@@ -7366,13 +7366,27 @@
   [(set_attr "op_type"  "RR<E>")
    (set_attr "z10prop" "z10_super_c_E1")])
 
-(define_insn_and_split "*negdi2_31"
+(define_insn "*negdi2_31"
   [(set (match_operand:DI 0 "register_operand" "=d")
         (neg:DI (match_operand:DI 1 "register_operand" "d")))
    (clobber (reg:CC CC_REGNUM))]
   "!TARGET_ZARCH"
-  "#"
-  "&& reload_completed"
+  "#")
+
+; Split a DImode NEG on 31bit into 2 SImode NEGs
+
+; Doing the twos complement separately on the SImode parts does an
+; unwanted +1 on the high part which needs to be subtracted afterwards
+; ... unless the +1 on the low part created an overflow.
+
+(define_split
+  [(set (match_operand:DI 0 "register_operand" "")
+        (neg:DI (match_operand:DI 1 "register_operand" "")))
+   (clobber (reg:CC CC_REGNUM))]
+  "!TARGET_ZARCH
+   && (REGNO (operands[0]) == REGNO (operands[1])
+      || s390_split_ok_p (operands[0], operands[1], DImode, 0))
+   && reload_completed"
   [(parallel
     [(set (match_dup 2) (neg:SI (match_dup 3)))
      (clobber (reg:CC CC_REGNUM))])
@@ -7394,6 +7408,40 @@
    operands[5] = operand_subword (operands[1], 1, 0, DImode);
    operands[6] = gen_label_rtx ();")
 
+; Like above but first make a copy of the low part of the src operand
+; since it might overlap with the high part of the destination.
+
+(define_split
+  [(set (match_operand:DI 0 "register_operand" "")
+        (neg:DI (match_operand:DI 1 "register_operand" "")))
+   (clobber (reg:CC CC_REGNUM))]
+  "!TARGET_ZARCH
+   && s390_split_ok_p (operands[0], operands[1], DImode, 1)
+   && reload_completed"
+  [; Make a backup of op5 first
+   (set (match_dup 4) (match_dup 5))
+   ; Setting op2 here might clobber op5
+   (parallel
+    [(set (match_dup 2) (neg:SI (match_dup 3)))
+     (clobber (reg:CC CC_REGNUM))])
+   (parallel
+    [(set (reg:CCAP CC_REGNUM)
+          (compare:CCAP (neg:SI (match_dup 4)) (const_int 0)))
+     (set (match_dup 4) (neg:SI (match_dup 4)))])
+   (set (pc)
+        (if_then_else (ne (reg:CCAP CC_REGNUM) (const_int 0))
+                      (pc)
+                      (label_ref (match_dup 6))))
+   (parallel
+    [(set (match_dup 2) (plus:SI (match_dup 2) (const_int -1)))
+     (clobber (reg:CC CC_REGNUM))])
+   (match_dup 6)]
+  "operands[2] = operand_subword (operands[0], 0, 0, DImode);
+   operands[3] = operand_subword (operands[1], 0, 0, DImode);
+   operands[4] = operand_subword (operands[0], 1, 0, DImode);
+   operands[5] = operand_subword (operands[1], 1, 0, DImode);
+   operands[6] = gen_label_rtx ();")
+
 ;
 ; neg(df|sf)2 instruction pattern(s).
 ;