Index: llvm/lib/Target/AVR/AVRISelLowering.cpp
===================================================================
--- llvm/lib/Target/AVR/AVRISelLowering.cpp
+++ llvm/lib/Target/AVR/AVRISelLowering.cpp
@@ -2142,16 +2142,41 @@
   insertMultibyteShift(MI, BB, Registers, ShiftAmt, ArithmeticShift);
 
   // Combine the 8-bit registers into 16-bit register pairs.
-  BuildMI(*BB, MI, dl, TII.get(AVR::REG_SEQUENCE), MI.getOperand(1).getReg())
-      .addReg(Registers[0].first, 0, Registers[0].second)
-      .addImm(AVR::sub_hi)
-      .addReg(Registers[1].first, 0, Registers[1].second)
-      .addImm(AVR::sub_lo);
-  BuildMI(*BB, MI, dl, TII.get(AVR::REG_SEQUENCE), MI.getOperand(0).getReg())
-      .addReg(Registers[2].first, 0, Registers[2].second)
-      .addImm(AVR::sub_hi)
-      .addReg(Registers[3].first, 0, Registers[3].second)
-      .addImm(AVR::sub_lo);
+  // This done either from LSB to MSB or from MSB to LSB, depending on the
+  // shift. It's an optimization so that the register allocator will use the
+  // fewest movs possible (which order we use isn't a correctness issue, just an
+  // optimization issue).
+  //   - lsl prefers starting from the most significant byte (2nd case).
+  //   - lshr prefers starting from the least significant byte (1st case).
+  //   - for ashr it depends on the number of shifted bytes.
+  // Some shift operations still don't get the most optimal mov sequences even
+  // with this distinction. TODO: figure out why and try to fix it (but we're
+  // already equal to or faster than avr-gcc in all cases except ashr 8).
+  if (ShiftAmt > 0 && (!ArithmeticShift || (ShiftAmt < 16 || ShiftAmt >= 22))) {
+    // Use the resulting registers starting with the least significant byte.
+    BuildMI(*BB, MI, dl, TII.get(AVR::REG_SEQUENCE), MI.getOperand(0).getReg())
+        .addReg(Registers[3].first, 0, Registers[3].second)
+        .addImm(AVR::sub_lo)
+        .addReg(Registers[2].first, 0, Registers[2].second)
+        .addImm(AVR::sub_hi);
+    BuildMI(*BB, MI, dl, TII.get(AVR::REG_SEQUENCE), MI.getOperand(1).getReg())
+        .addReg(Registers[1].first, 0, Registers[1].second)
+        .addImm(AVR::sub_lo)
+        .addReg(Registers[0].first, 0, Registers[0].second)
+        .addImm(AVR::sub_hi);
+  } else {
+    // Use the resulting registers starting with the most significant byte.
+    BuildMI(*BB, MI, dl, TII.get(AVR::REG_SEQUENCE), MI.getOperand(1).getReg())
+        .addReg(Registers[0].first, 0, Registers[0].second)
+        .addImm(AVR::sub_hi)
+        .addReg(Registers[1].first, 0, Registers[1].second)
+        .addImm(AVR::sub_lo);
+    BuildMI(*BB, MI, dl, TII.get(AVR::REG_SEQUENCE), MI.getOperand(0).getReg())
+        .addReg(Registers[2].first, 0, Registers[2].second)
+        .addImm(AVR::sub_hi)
+        .addReg(Registers[3].first, 0, Registers[3].second)
+        .addImm(AVR::sub_lo);
+  }
 
   // Remove the pseudo instruction.
   MI.eraseFromParent();
Index: llvm/test/CodeGen/AVR/shift32.ll
===================================================================
--- llvm/test/CodeGen/AVR/shift32.ll
+++ llvm/test/CodeGen/AVR/shift32.ll
@@ -310,10 +310,9 @@
 ; CHECK-NEXT:    rol r24
 ; CHECK-NEXT:    rol r25
 ; CHECK-NEXT:    rol r19
+; CHECK-NEXT:    mov r22, r23
+; CHECK-NEXT:    mov r23, r24
 ; CHECK-NEXT:    mov r18, r25
-; CHECK-NEXT:    mov r25, r24
-; CHECK-NEXT:    mov r24, r23
-; CHECK-NEXT:    movw r22, r24
 ; CHECK-NEXT:    movw r24, r18
 ; CHECK-NEXT:    ret
   %res = lshr i32 %a, 6
@@ -329,10 +328,9 @@
 ; CHECK-NEXT:    rol r25
 ; CHECK-NEXT:    mov r19, r1
 ; CHECK-NEXT:    rol r19
+; CHECK-NEXT:    mov r22, r23
+; CHECK-NEXT:    mov r23, r24
 ; CHECK-NEXT:    mov r18, r25
-; CHECK-NEXT:    mov r25, r24
-; CHECK-NEXT:    mov r24, r23
-; CHECK-NEXT:    movw r22, r24
 ; CHECK-NEXT:    movw r24, r18
 ; CHECK-NEXT:    ret
   %res = lshr i32 %a, 7
@@ -342,12 +340,10 @@
 define i32 @lshr_i32_8(i32 %a) {
 ; CHECK-LABEL: lshr_i32_8:
 ; CHECK:       ; %bb.0:
-; CHECK-NEXT:    mov r19, r1
-; CHECK-NEXT:    mov r18, r25
-; CHECK-NEXT:    mov r25, r24
-; CHECK-NEXT:    mov r24, r23
-; CHECK-NEXT:    movw r22, r24
-; CHECK-NEXT:    movw r24, r18
+; CHECK-NEXT:    mov r22, r23
+; CHECK-NEXT:    mov r23, r24
+; CHECK-NEXT:    mov r24, r25
+; CHECK-NEXT:    mov r25, r1
 ; CHECK-NEXT:    ret
   %res = lshr i32 %a, 8
   ret i32 %res
@@ -356,11 +352,10 @@
 define i32 @lshr_i32_24(i32 %a) {
 ; CHECK-LABEL: lshr_i32_24:
 ; CHECK:       ; %bb.0:
-; CHECK-NEXT:    mov r19, r1
-; CHECK-NEXT:    mov r18, r1
-; CHECK-NEXT:    mov r23, r1
 ; CHECK-NEXT:    mov r22, r25
-; CHECK-NEXT:    movw r24, r18
+; CHECK-NEXT:    mov r23, r1
+; CHECK-NEXT:    mov r24, r1
+; CHECK-NEXT:    mov r25, r1
 ; CHECK-NEXT:    ret
   %res = lshr i32 %a, 24
   ret i32 %res
@@ -372,9 +367,9 @@
 ; CHECK-NEXT:    lsl r25
 ; CHECK-NEXT:    mov r22, r1
 ; CHECK-NEXT:    rol r22
-; CHECK-NEXT:    mov r25, r1
-; CHECK-NEXT:    mov r24, r1
 ; CHECK-NEXT:    mov r23, r1
+; CHECK-NEXT:    mov r24, r1
+; CHECK-NEXT:    mov r25, r1
 ; CHECK-NEXT:    ret
   %res = lshr i32 %a, 31
   ret i32 %res
@@ -441,27 +436,25 @@
 ; CHECK-NEXT:    rol r24
 ; CHECK-NEXT:    rol r25
 ; CHECK-NEXT:    sbc r19, r19
+; CHECK-NEXT:    mov r22, r23
+; CHECK-NEXT:    mov r23, r24
 ; CHECK-NEXT:    mov r18, r25
-; CHECK-NEXT:    mov r25, r24
-; CHECK-NEXT:    mov r24, r23
-; CHECK-NEXT:    movw r22, r24
 ; CHECK-NEXT:    movw r24, r18
 ; CHECK-NEXT:    ret
   %res = ashr i32 %a, 7
   ret i32 %res
 }
 
-; TODO: this could be optimized to 4 movs, instead of 6.
+; TODO: this could be optimized to 4 movs, instead of 5.
 define i32 @ashr_i32_8(i32 %a) {
 ; CHECK-LABEL: ashr_i32_8:
 ; CHECK:       ; %bb.0:
 ; CHECK-NEXT:    mov r19, r25
 ; CHECK-NEXT:    lsl r19
 ; CHECK-NEXT:    sbc r19, r19
+; CHECK-NEXT:    mov r22, r23
+; CHECK-NEXT:    mov r23, r24
 ; CHECK-NEXT:    mov r18, r25
-; CHECK-NEXT:    mov r25, r24
-; CHECK-NEXT:    mov r24, r23
-; CHECK-NEXT:    movw r22, r24
 ; CHECK-NEXT:    movw r24, r18
 ; CHECK-NEXT:    ret
   %res = ashr i32 %a, 8
@@ -485,13 +478,13 @@
 ; CHECK:       ; %bb.0:
 ; CHECK-NEXT:    lsl r24
 ; CHECK-NEXT:    rol r25
-; CHECK-NEXT:    sbc r19, r19
+; CHECK-NEXT:    sbc r18, r18
 ; CHECK-NEXT:    lsl r24
 ; CHECK-NEXT:    rol r25
-; CHECK-NEXT:    mov r23, r19
+; CHECK-NEXT:    mov r23, r18
 ; CHECK-NEXT:    rol r23
-; CHECK-NEXT:    mov r18, r19
 ; CHECK-NEXT:    mov r22, r25
+; CHECK-NEXT:    mov r19, r18
 ; CHECK-NEXT:    movw r24, r18
 ; CHECK-NEXT:    ret
   %res = ashr i32 %a, 22
@@ -503,11 +496,10 @@
 ; CHECK:       ; %bb.0:
 ; CHECK-NEXT:    lsl r24
 ; CHECK-NEXT:    rol r25
-; CHECK-NEXT:    sbc r19, r19
-; CHECK-NEXT:    mov r18, r19
-; CHECK-NEXT:    mov r23, r19
+; CHECK-NEXT:    sbc r23, r23
 ; CHECK-NEXT:    mov r22, r25
-; CHECK-NEXT:    movw r24, r18
+; CHECK-NEXT:    mov r24, r23
+; CHECK-NEXT:    mov r25, r23
 ; CHECK-NEXT:    ret
   %res = ashr i32 %a, 23
   ret i32 %res
@@ -517,13 +509,12 @@
 ; CHECK-LABEL: ashr_i32_30:
 ; CHECK:       ; %bb.0:
 ; CHECK-NEXT:    lsl r25
-; CHECK-NEXT:    sbc r19, r19
+; CHECK-NEXT:    sbc r23, r23
 ; CHECK-NEXT:    lsl r25
-; CHECK-NEXT:    mov r22, r19
+; CHECK-NEXT:    mov r22, r23
 ; CHECK-NEXT:    rol r22
-; CHECK-NEXT:    mov r18, r19
-; CHECK-NEXT:    mov r23, r19
-; CHECK-NEXT:    movw r24, r18
+; CHECK-NEXT:    mov r24, r23
+; CHECK-NEXT:    mov r25, r23
 ; CHECK-NEXT:    ret
   %res = ashr i32 %a, 30
   ret i32 %res
@@ -533,8 +524,8 @@
 ; CHECK-LABEL: ashr_i32_31:
 ; CHECK:       ; %bb.0:
 ; CHECK-NEXT:    lsl r25
-; CHECK-NEXT:    sbc r23, r23
-; CHECK-NEXT:    mov r22, r23
+; CHECK-NEXT:    sbc r22, r22
+; CHECK-NEXT:    mov r23, r22
 ; CHECK-NEXT:    movw r24, r22
 ; CHECK-NEXT:    ret
   %res = ashr i32 %a, 31