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/PPCSubtarget.h b/lib/Target/PowerPC/PPCSubtarget.h
index bf5bd84..3958bc9 100644
--- a/lib/Target/PowerPC/PPCSubtarget.h
+++ b/lib/Target/PowerPC/PPCSubtarget.h
@@ -78,6 +78,7 @@
   bool HasQPX;
   bool HasFSQRT;
   bool HasSTFIWX;
+  bool HasLFIWAX;
   bool HasFPRND;
   bool HasISEL;
   bool HasPOPCNTD;
@@ -158,6 +159,7 @@
   // Specific obvious features.
   bool hasFSQRT() const { return HasFSQRT; }
   bool hasSTFIWX() const { return HasSTFIWX; }
+  bool hasLFIWAX() const { return HasLFIWAX; }
   bool hasFPRND() const { return HasFPRND; }
   bool hasAltivec() const { return HasAltivec; }
   bool hasQPX() const { return HasQPX; }