Add the PPC lfiwax instruction

This instruction is available on modern PPC64 CPUs, and is now used
to improve the SINT_TO_FP lowering (by eliminating the need for the
separate sign extension instruction and decreasing the amount of
needed stack space).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178446 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCISelLowering.h b/lib/Target/PowerPC/PPCISelLowering.h
index bce05a1..a924ac4 100644
--- a/lib/Target/PowerPC/PPCISelLowering.h
+++ b/lib/Target/PowerPC/PPCISelLowering.h
@@ -242,6 +242,11 @@
       /// or i32.
       LBRX,
 
+      /// GPRC, CHAIN = LFIWAX CHAIN, Ptr - This is a floating-point
+      /// load which sign-extends from a 32-bit integer value into the
+      /// destination 64-bit register.
+      LFIWAX,
+
       /// G8RC = ADDIS_TOC_HA %X2, Symbol - For medium and large code model,
       /// produces an ADDIS8 instruction that adds the TOC base register to
       /// sym@toc@ha.