Index: llvm/trunk/lib/Target/X86/X86InstrInfo.cpp
===================================================================
--- llvm/trunk/lib/Target/X86/X86InstrInfo.cpp
+++ llvm/trunk/lib/Target/X86/X86InstrInfo.cpp
@@ -3954,13 +3954,14 @@
   case X86::MOV32rm:
   case X86::MOVSSrm:
   case X86::VMOVSSZrm:
+  case X86::VMOVSSrm:
   case X86::KMOVDkm:
     MemBytes = 4;
     return true;
   case X86::MOV64rm:
   case X86::LD_Fp64m:
   case X86::MOVSDrm:
-  case X86::VMOVSSrm:
+  case X86::VMOVSDrm:
   case X86::VMOVSDZrm:
   case X86::MMX_MOVD64rm:
   case X86::MMX_MOVQ64rm:
@@ -3973,7 +3974,6 @@
   case X86::MOVUPDrm:
   case X86::MOVDQArm:
   case X86::MOVDQUrm:
-  case X86::VMOVSDrm:
   case X86::VMOVAPSrm:
   case X86::VMOVUPSrm:
   case X86::VMOVAPDrm:
Index: llvm/trunk/test/CodeGen/X86/pr30821.mir
===================================================================
--- llvm/trunk/test/CodeGen/X86/pr30821.mir
+++ llvm/trunk/test/CodeGen/X86/pr30821.mir
@@ -111,6 +111,74 @@
 
     MOVUPDmr %stack.2.india, 1, $noreg, 0, $noreg, killed %2 :: (volatile dereferenceable store 16 into %ir.india)
 
+
+    ; Test some sequences that _should_ be eliminated
+    %3:vr128 = MOVUPDrm %stack.2.india, 1, $noreg, 0, $noreg :: (volatile dereferenceable load 16 from %ir.india)
+
+    %32:fr64 = VMOVSDrm %stack.2.india, 1, $noreg, 0, $noreg :: (dereferenceable load 8 from %ir.india)
+    %33:fr64 = COPY killed %32
+    VMOVSDmr %stack.2.india, 1, $noreg, 0, $noreg, killed %33 :: (store 8 into %ir.india)
+
+    ; This is the spill introduced by regalloc; we check that the inner dead
+    ; store and load were eliminated
+    ; CHECK: MOVAPSmr %stack.3, 1, $noreg, 0, $noreg, killed renamable $xmm{{[0-9]+}} :: (store 16 into %stack.3)
+    ; CHECK-NEXT:renamable $xmm{{[0-9]+}} = MOVAPSrm %stack.3, 1, $noreg, 0, $noreg :: (load 16 from %stack.3)
+
+    MOVUPDmr %stack.2.india, 1, $noreg, 0, $noreg, killed %3 :: (volatile dereferenceable store 16 into %ir.india)
+
+
+    ; Moves with different encodings but same size should be eliminated
+    %4:vr128 = MOVUPDrm %stack.2.india, 1, $noreg, 0, $noreg :: (volatile dereferenceable load 16 from %ir.india)
+
+    %42:fr32 = MOVSSrm %stack.2.india, 1, $noreg, 0, $noreg :: (dereferenceable load 4 from %ir.india)
+    %43:fr32 = COPY killed %42
+    VMOVSSZmr %stack.2.india, 1, $noreg, 0, $noreg, killed %43 :: (store 4 into %ir.india)
+
+    ; CHECK: MOVAPSmr %stack.3, 1, $noreg, 0, $noreg, killed renamable $xmm{{[0-9]+}} :: (store 16 into %stack.3)
+    ; CHECK-NEXT:renamable $xmm{{[0-9]+}} = MOVAPSrm %stack.3, 1, $noreg, 0, $noreg :: (load 16 from %stack.3)
+
+    MOVUPDmr %stack.2.india, 1, $noreg, 0, $noreg, killed %4 :: (volatile dereferenceable store 16 into %ir.india)
+
+
+    ; Same deal with double-size
+    %5:vr128 = MOVUPDrm %stack.2.india, 1, $noreg, 0, $noreg :: (volatile dereferenceable load 16 from %ir.india)
+
+    %52:fr64 = MOVSDrm %stack.2.india, 1, $noreg, 0, $noreg :: (dereferenceable load 8 from %ir.india)
+    %53:fr64 = COPY killed %52
+    VMOVSDZmr %stack.2.india, 1, $noreg, 0, $noreg, killed %53 :: (store 8 into %ir.india)
+
+    ; CHECK: MOVAPSmr %stack.3, 1, $noreg, 0, $noreg, killed renamable $xmm{{[0-9]+}} :: (store 16 into %stack.3)
+    ; CHECK-NEXT:renamable $xmm{{[0-9]+}} = MOVAPSrm %stack.3, 1, $noreg, 0, $noreg :: (load 16 from %stack.3)
+
+    MOVUPDmr %stack.2.india, 1, $noreg, 0, $noreg, killed %5 :: (volatile dereferenceable store 16 into %ir.india)
+
+
+    ; Last two repeated, with load/store opcode flipped
+    %6:vr128 = MOVUPDrm %stack.2.india, 1, $noreg, 0, $noreg :: (volatile dereferenceable load 16 from %ir.india)
+
+    %62:fr32 = VMOVSSZrm %stack.2.india, 1, $noreg, 0, $noreg :: (dereferenceable load 4 from %ir.india)
+    %63:fr32 = COPY killed %62
+    MOVSSmr %stack.2.india, 1, $noreg, 0, $noreg, killed %63 :: (store 4 into %ir.india)
+
+    ; CHECK: MOVAPSmr %stack.3, 1, $noreg, 0, $noreg, killed renamable $xmm{{[0-9]+}} :: (store 16 into %stack.3)
+    ; CHECK-NEXT:renamable $xmm{{[0-9]+}} = MOVAPSrm %stack.3, 1, $noreg, 0, $noreg :: (load 16 from %stack.3)
+
+    MOVUPDmr %stack.2.india, 1, $noreg, 0, $noreg, killed %6 :: (volatile dereferenceable store 16 into %ir.india)
+
+
+    ; Flipped double-size different-encoding test
+    %7:vr128 = MOVUPDrm %stack.2.india, 1, $noreg, 0, $noreg :: (volatile dereferenceable load 16 from %ir.india)
+
+    %72:fr64 = VMOVSDZrm %stack.2.india, 1, $noreg, 0, $noreg :: (dereferenceable load 8 from %ir.india)
+    %73:fr64 = COPY killed %72
+    MOVSDmr %stack.2.india, 1, $noreg, 0, $noreg, killed %73 :: (store 8 into %ir.india)
+
+    ; CHECK: MOVAPSmr %stack.3, 1, $noreg, 0, $noreg, killed renamable $xmm{{[0-9]+}} :: (store 16 into %stack.3)
+    ; CHECK-NEXT:renamable $xmm{{[0-9]+}} = MOVAPSrm %stack.3, 1, $noreg, 0, $noreg :: (load 16 from %stack.3)
+
+    MOVUPDmr %stack.2.india, 1, $noreg, 0, $noreg, killed %7 :: (volatile dereferenceable store 16 into %ir.india)
+
+
     ; Stores of first 15 $xmm registers to keep them live across the middle of
     ; this bb.
     MOVUPDmr %stack.2.india, 1, $noreg, 0, $noreg, killed $xmm0 :: (volatile dereferenceable store 16 into %ir.india)