Index: lib/Target/PowerPC/PPCInstrInfo.h
===================================================================
--- lib/Target/PowerPC/PPCInstrInfo.h
+++ lib/Target/PowerPC/PPCInstrInfo.h
@@ -414,7 +414,8 @@
                               MachineInstr **KilledDef = nullptr) const;
   void replaceInstrWithLI(MachineInstr &MI, const LoadImmediateInfo &LII) const;
 
-  bool instrHasImmForm(const MachineInstr &MI, ImmInstrInfo &III) const;
+  bool instrHasImmForm(const MachineInstr &MI, ImmInstrInfo &III,
+                       bool PostRA) const;
 
   /// getRegNumForOperand - some operands use different numbering schemes
   /// for the same registers. For example, a VSX instruction may have any of
Index: lib/Target/PowerPC/PPCInstrInfo.cpp
===================================================================
--- lib/Target/PowerPC/PPCInstrInfo.cpp
+++ lib/Target/PowerPC/PPCInstrInfo.cpp
@@ -2319,7 +2319,7 @@
       Opc == PPC::RLDICL_32 || Opc == PPC::RLDICL_32_64 ||
       Opc == PPC::RLWINM || Opc == PPC::RLWINMo ||
       Opc == PPC::RLWINM8 || Opc == PPC::RLWINM8o;
-    if (!instrHasImmForm(MI, III) && !ConvertibleImmForm)
+    if (!instrHasImmForm(MI, III, true) && !ConvertibleImmForm)
       return nullptr;
 
     // Don't convert or %X, %Y, %Y since that's just a register move.
@@ -2421,7 +2421,7 @@
     *KilledDef = DefMI;
 
   ImmInstrInfo III;
-  bool HasImmForm = instrHasImmForm(MI, III);
+  bool HasImmForm = instrHasImmForm(MI, III, PostRA);
   // If this is a reg+reg instruction that has a reg+imm form,
   // and one of the operands is produced by an add-immediate,
   // try to convert it.
@@ -2645,7 +2645,7 @@
 }
 
 bool PPCInstrInfo::instrHasImmForm(const MachineInstr &MI,
-                                   ImmInstrInfo &III) const {
+                                   ImmInstrInfo &III, bool PostRA) const {
   unsigned Opc = MI.getOpcode();
   // The vast majority of the instructions would need their operand 2 replaced
   // with an immediate when switching to the reg+imm form. A marked exception
@@ -2946,7 +2946,9 @@
     case PPC::STFDUX: III.ImmOpcode = PPC::STFDU; break;
     }
     break;
-  // Power9 only.
+  // Power9 only. Some of these are being replaced by pseudo-instructions which
+  // are expanded post-ra. We cannot do anything about these if we are already
+  // post-ra.
   case PPC::LXVX:
   case PPC::LXSSPX:
   case PPC::LXSDX:
@@ -2969,11 +2971,15 @@
       III.ImmMustBeMultipleOf = 16;
       break;
     case PPC::LXSSPX:
-      III.ImmOpcode = PPC::LXSSP;
+      if (PostRA)
+        return false;
+      III.ImmOpcode = PPC::DFLOADf32;
       III.ImmMustBeMultipleOf = 4;
       break;
     case PPC::LXSDX:
-      III.ImmOpcode = PPC::LXSD;
+      if (PostRA)
+        return false;
+      III.ImmOpcode = PPC::DFLOADf64;
       III.ImmMustBeMultipleOf = 4;
       break;
     case PPC::STXVX:
@@ -2981,11 +2987,15 @@
       III.ImmMustBeMultipleOf = 16;
       break;
     case PPC::STXSSPX:
-      III.ImmOpcode = PPC::STXSSP;
+      if (PostRA)
+        return false;
+      III.ImmOpcode = PPC::DFSTOREf32;
       III.ImmMustBeMultipleOf = 4;
       break;
     case PPC::STXSDX:
-      III.ImmOpcode = PPC::STXSD;
+      if (PostRA)
+        return false;
+      III.ImmOpcode = PPC::DFSTOREf64;
       III.ImmMustBeMultipleOf = 4;
       break;
     }
Index: test/CodeGen/PowerPC/convert-rr-to-ri-instrs.mir
===================================================================
--- test/CodeGen/PowerPC/convert-rr-to-ri-instrs.mir
+++ test/CodeGen/PowerPC/convert-rr-to-ri-instrs.mir
@@ -3265,15 +3265,15 @@
     %4 = INSERT_SUBREG %5, killed %3, 1
     %6 = LI8 100
     %7 = LXSDX %0, killed %6, implicit $rm :: (load 8 from %ir.arrayidx, !tbaa !12)
-    ; CHECK: LXSD 100, %0
-    ; CHECK-LATE: lxsd 0, 100(3)
+    ; CHECK: DFLOADf64 100, %0
+    ; FIXME: We should be able to transform this in pre-emit based on reg number
     %8 = ADDI %2, 2
     %10 = IMPLICIT_DEF
     %9 = INSERT_SUBREG %10, killed %8, 1
     %11 = LI8 -120
     %12 = LXSDX %0, killed %11, implicit $rm :: (load 8 from %ir.arrayidx3, !tbaa !12)
-    ; CHECK: LXSD -120, %0
-    ; CHECK-LATE: lxsd 1, -120(3)
+    ; CHECK: DFLOADf64 -120, %0
+    ; FIXME: We should be able to transform this in pre-emit based on reg number
     %13 = XSADDDP killed %7, killed %12, implicit $rm
     $f1 = COPY %13
     BLR8 implicit $lr8, implicit $rm, implicit $f1
@@ -3338,15 +3338,15 @@
     %4 = INSERT_SUBREG %5, killed %3, 1
     %6 = LI8 96
     %7 = LXSSPX %0, killed %6 :: (load 4 from %ir.arrayidx, !tbaa !14)
-    ; CHECK: LXSSP 96, %0
-    ; CHECK-LATE: lxssp 0, 96(3)
+    ; CHECK: DFLOADf32 96, %0
+    ; FIXME: We should be able to transform this in pre-emit based on reg number
     %8 = ADDI %2, 2
     %10 = IMPLICIT_DEF
     %9 = INSERT_SUBREG %10, killed %8, 1
     %11 = LI8 -92
     %12 = LXSSPX %0, killed %11 :: (load 4 from %ir.arrayidx3, !tbaa !14)
-    ; CHECK: LXSSP -92, %0
-    ; CHECK-LATE: lxssp 1, -92(3)
+    ; CHECK: DFLOADf32 -92, %0
+    ; FIXME: We should be able to transform this in pre-emit based on reg number
     %13 = XSADDSP killed %7, killed %12
     $f1 = COPY %13
     BLR8 implicit $lr8, implicit $rm, implicit $f1
@@ -6031,8 +6031,8 @@
     %0 = COPY $x3
     %3 = LI8 444
     STXSSPX %1, %0, killed %3 :: (store 4 into %ir.arrayidx, !tbaa !14)
-    ; CHECK: STXSSP %1, 444, %0
-    ; CHECK-LATE: stxssp 1, 444(3)
+    ; CHECK: DFSTOREf32 %1, 444, %0
+    ; FIXME: We should be able to transform this in pre-emit based on reg number
     BLR8 implicit $lr8, implicit $rm
 
 ...
@@ -6083,8 +6083,8 @@
     %0 = COPY $x3
     %3 = LI8 4
     STXSDX %1, %0, killed %3, implicit $rm :: (store 8 into %ir.arrayidx, !tbaa !12)
-    ; CHECK: STXSD %1, 4, %0
-    ; CHECK-LATE: stxsd 1, 4(3)
+    ; CHECK: DFSTOREf64 %1, 4, %0
+    ; FIXME: We should be able to transform this in pre-emit based on reg number
     BLR8 implicit $lr8, implicit $rm
 
 ...