Fix instruction encoding for "isel" on PowerPC,
using a new instruction format AForm_4.

llvm-svn: 167860
diff --git a/llvm/lib/Target/PowerPC/PPCInstr64Bit.td b/llvm/lib/Target/PowerPC/PPCInstr64Bit.td
index 6c2249a..4f24d2a 100644
--- a/llvm/lib/Target/PowerPC/PPCInstr64Bit.td
+++ b/llvm/lib/Target/PowerPC/PPCInstr64Bit.td
@@ -511,7 +511,7 @@
                      "rlwinm $rA, $rS, $SH, $MB, $ME", IntGeneral,
                      []>;
 
-def ISEL8   : AForm_1<31, 15,
+def ISEL8   : AForm_4<31, 15,
                      (outs G8RC:$rT), (ins G8RC:$rA, G8RC:$rB, pred:$cond),
                      "isel $rT, $rA, $rB, $cond", IntGeneral,
                      []>;