diff --git a/llvm/lib/Target/CSKY/CSKYInstrInfo.td b/llvm/lib/Target/CSKY/CSKYInstrInfo.td
--- a/llvm/lib/Target/CSKY/CSKYInstrInfo.td
+++ b/llvm/lib/Target/CSKY/CSKYInstrInfo.td
@@ -158,6 +158,21 @@
   let DecoderMethod = "decodeImmShiftOpValue";
 }
 
+// Optimize constant materialization with BMASKI32.
+def imm_bmask_XFORM : SDNodeXForm<imm, [{
+  uint32_t I = N->getZExtValue() + 1;
+  if (I == 0)
+    return CurDAG->getTargetConstant(32, SDLoc(N),
+                                     N->getValueType(0));
+  else
+    return CurDAG->getTargetConstant(llvm::Log2_32(I), SDLoc(N),
+                                     N->getValueType(0));
+}]>;
+def imm_bmask : PatLeaf<(imm), [{
+  uint32_t I = N->getZExtValue() + 1;
+  return (llvm::popcount(I) == 1 && I >= 0x20000) || I == 0;
+}]>;
+
 def CSKYSymbol : AsmOperandClass {
   let Name = "CSKYSymbol";
   let RenderMethod = "addImmOperands";
@@ -1413,9 +1428,12 @@
 }
 
 // Constant materialize patterns.
-let Predicates = [iHasE2] in
+let Predicates = [iHasE2] in {
   def : Pat<(i32 imm:$imm),
             (ORI32 (MOVIH32 (uimm32_hi16 imm:$imm)), (uimm32_lo16 imm:$imm))>;
+  def : Pat<(i32 imm_bmask:$imm),
+            (BMASKI32 (imm_bmask_XFORM imm_bmask:$imm))>;
+}
 
 // Other operations.
 let Predicates = [iHasE2] in {
diff --git a/llvm/test/CodeGen/CSKY/base-i.ll b/llvm/test/CodeGen/CSKY/base-i.ll
--- a/llvm/test/CodeGen/CSKY/base-i.ll
+++ b/llvm/test/CodeGen/CSKY/base-i.ll
@@ -86,6 +86,35 @@
   ret i32 %add
 }
 
+define i32 @addRI_0x1ffff(i32 %x) {
+; CHECK-LABEL: addRI_0x1ffff:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    bmaski32 a1, 17
+; CHECK-NEXT:    addu16 a0, a1
+; CHECK-NEXT:    rts16
+;
+; GENERIC-LABEL: addRI_0x1ffff:
+; GENERIC:       # %bb.0: # %entry
+; GENERIC-NEXT:    .cfi_def_cfa_offset 0
+; GENERIC-NEXT:    subi16 sp, sp, 4
+; GENERIC-NEXT:    .cfi_def_cfa_offset 4
+; GENERIC-NEXT:    movi16 a1, 0
+; GENERIC-NEXT:    lsli16 a1, a1, 24
+; GENERIC-NEXT:    movi16 a2, 1
+; GENERIC-NEXT:    lsli16 a2, a2, 16
+; GENERIC-NEXT:    or16 a2, a1
+; GENERIC-NEXT:    movi16 a1, 255
+; GENERIC-NEXT:    lsli16 a3, a1, 8
+; GENERIC-NEXT:    or16 a3, a2
+; GENERIC-NEXT:    or16 a3, a1
+; GENERIC-NEXT:    addu16 a0, a0, a3
+; GENERIC-NEXT:    addi16 sp, sp, 4
+; GENERIC-NEXT:    rts16
+entry:
+  %add = add nsw i32 %x, 131071
+  ret i32 %add
+}
+
 define i32 @addRI_X(i32 %x) {
 ; CHECK-LABEL: addRI_X:
 ; CHECK:       # %bb.0: # %entry
@@ -393,8 +422,7 @@
 ; CHECK-LABEL: SUB_LONG_I:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    clrc32
-; CHECK-NEXT:    movih32 a2, 65535
-; CHECK-NEXT:    ori32 a2, a2, 65535
+; CHECK-NEXT:    bmaski32 a2, 32
 ; CHECK-NEXT:    addc16 a0, a2
 ; CHECK-NEXT:    addc16 a1, a2
 ; CHECK-NEXT:    rts16
@@ -660,7 +688,7 @@
 ; GENERIC-NEXT:    subi16 sp, sp, 4
 ; GENERIC-NEXT:    .cfi_def_cfa_offset 8
 ; GENERIC-NEXT:    mov16 a2, a0
-; GENERIC-NEXT:    lrw32 a3, [.LCPI29_0]
+; GENERIC-NEXT:    lrw32 a3, [.LCPI30_0]
 ; GENERIC-NEXT:    mov16 a0, a1
 ; GENERIC-NEXT:    mov16 a1, a2
 ; GENERIC-NEXT:    jsr16 a3
@@ -671,7 +699,7 @@
 ; GENERIC-NEXT:    .p2align 1
 ; GENERIC-NEXT:  # %bb.1:
 ; GENERIC-NEXT:    .p2align 2, 0x0
-; GENERIC-NEXT:  .LCPI29_0:
+; GENERIC-NEXT:  .LCPI30_0:
 ; GENERIC-NEXT:    .long __udivsi3
 entry:
   %udiv = udiv  i32 %y, %x
@@ -693,7 +721,7 @@
 ; GENERIC-NEXT:    .cfi_offset lr, -4
 ; GENERIC-NEXT:    subi16 sp, sp, 4
 ; GENERIC-NEXT:    .cfi_def_cfa_offset 8
-; GENERIC-NEXT:    lrw32 a2, [.LCPI30_0]
+; GENERIC-NEXT:    lrw32 a2, [.LCPI31_0]
 ; GENERIC-NEXT:    movi16 a1, 10
 ; GENERIC-NEXT:    jsr16 a2
 ; GENERIC-NEXT:    addi16 sp, sp, 4
@@ -703,7 +731,7 @@
 ; GENERIC-NEXT:    .p2align 1
 ; GENERIC-NEXT:  # %bb.1:
 ; GENERIC-NEXT:    .p2align 2, 0x0
-; GENERIC-NEXT:  .LCPI30_0:
+; GENERIC-NEXT:  .LCPI31_0:
 ; GENERIC-NEXT:    .long __udivsi3
 entry:
   %udiv = udiv  i32 %x, 10
@@ -734,7 +762,7 @@
 ; GENERIC-NEXT:    or16 a2, a1
 ; GENERIC-NEXT:    movi16 a1, 1
 ; GENERIC-NEXT:    or16 a1, a2
-; GENERIC-NEXT:    lrw32 a2, [.LCPI31_0]
+; GENERIC-NEXT:    lrw32 a2, [.LCPI32_0]
 ; GENERIC-NEXT:    jsr16 a2
 ; GENERIC-NEXT:    addi16 sp, sp, 4
 ; GENERIC-NEXT:    ld32.w lr, (sp, 0) # 4-byte Folded Reload
@@ -743,7 +771,7 @@
 ; GENERIC-NEXT:    .p2align 1
 ; GENERIC-NEXT:  # %bb.1:
 ; GENERIC-NEXT:    .p2align 2, 0x0
-; GENERIC-NEXT:  .LCPI31_0:
+; GENERIC-NEXT:  .LCPI32_0:
 ; GENERIC-NEXT:    .long __udivsi3
 entry:
   %udiv = udiv  i32 %x, 4097
@@ -779,7 +807,7 @@
 ; GENERIC-NEXT:    or16 a1, a3
 ; GENERIC-NEXT:    and16 a2, a1
 ; GENERIC-NEXT:    and16 a1, a0
-; GENERIC-NEXT:    lrw32 a3, [.LCPI32_0]
+; GENERIC-NEXT:    lrw32 a3, [.LCPI33_0]
 ; GENERIC-NEXT:    mov16 a0, a2
 ; GENERIC-NEXT:    jsr16 a3
 ; GENERIC-NEXT:    addi16 sp, sp, 4
@@ -790,7 +818,7 @@
 ; GENERIC-NEXT:    .p2align 1
 ; GENERIC-NEXT:  # %bb.1:
 ; GENERIC-NEXT:    .p2align 2, 0x0
-; GENERIC-NEXT:  .LCPI32_0:
+; GENERIC-NEXT:  .LCPI33_0:
 ; GENERIC-NEXT:    .long __udivsi3
 entry:
   %udiv = udiv  i16 %y, %x
@@ -854,7 +882,7 @@
 ; GENERIC-NEXT:    movi16 a1, 255
 ; GENERIC-NEXT:    and16 a2, a1
 ; GENERIC-NEXT:    and16 a1, a0
-; GENERIC-NEXT:    lrw32 a3, [.LCPI34_0]
+; GENERIC-NEXT:    lrw32 a3, [.LCPI35_0]
 ; GENERIC-NEXT:    mov16 a0, a2
 ; GENERIC-NEXT:    jsr16 a3
 ; GENERIC-NEXT:    addi16 sp, sp, 4
@@ -864,7 +892,7 @@
 ; GENERIC-NEXT:    .p2align 1
 ; GENERIC-NEXT:  # %bb.1:
 ; GENERIC-NEXT:    .p2align 2, 0x0
-; GENERIC-NEXT:  .LCPI34_0:
+; GENERIC-NEXT:  .LCPI35_0:
 ; GENERIC-NEXT:    .long __udivsi3
 entry:
   %udiv = udiv  i8 %y, %x
@@ -912,7 +940,7 @@
 ; GENERIC-NEXT:    subi16 sp, sp, 4
 ; GENERIC-NEXT:    .cfi_def_cfa_offset 8
 ; GENERIC-NEXT:    mov16 a2, a0
-; GENERIC-NEXT:    lrw32 a3, [.LCPI36_0]
+; GENERIC-NEXT:    lrw32 a3, [.LCPI37_0]
 ; GENERIC-NEXT:    mov16 a0, a1
 ; GENERIC-NEXT:    mov16 a1, a2
 ; GENERIC-NEXT:    jsr16 a3
@@ -923,7 +951,7 @@
 ; GENERIC-NEXT:    .p2align 1
 ; GENERIC-NEXT:  # %bb.1:
 ; GENERIC-NEXT:    .p2align 2, 0x0
-; GENERIC-NEXT:  .LCPI36_0:
+; GENERIC-NEXT:  .LCPI37_0:
 ; GENERIC-NEXT:    .long __divsi3
 entry:
   %sdiv = sdiv  i32 %y, %x
@@ -945,7 +973,7 @@
 ; GENERIC-NEXT:    .cfi_offset lr, -4
 ; GENERIC-NEXT:    subi16 sp, sp, 4
 ; GENERIC-NEXT:    .cfi_def_cfa_offset 8
-; GENERIC-NEXT:    lrw32 a2, [.LCPI37_0]
+; GENERIC-NEXT:    lrw32 a2, [.LCPI38_0]
 ; GENERIC-NEXT:    movi16 a1, 10
 ; GENERIC-NEXT:    jsr16 a2
 ; GENERIC-NEXT:    addi16 sp, sp, 4
@@ -955,7 +983,7 @@
 ; GENERIC-NEXT:    .p2align 1
 ; GENERIC-NEXT:  # %bb.1:
 ; GENERIC-NEXT:    .p2align 2, 0x0
-; GENERIC-NEXT:  .LCPI37_0:
+; GENERIC-NEXT:  .LCPI38_0:
 ; GENERIC-NEXT:    .long __divsi3
 entry:
   %sdiv = sdiv  i32 %x, 10
@@ -986,7 +1014,7 @@
 ; GENERIC-NEXT:    or16 a2, a1
 ; GENERIC-NEXT:    movi16 a1, 1
 ; GENERIC-NEXT:    or16 a1, a2
-; GENERIC-NEXT:    lrw32 a2, [.LCPI38_0]
+; GENERIC-NEXT:    lrw32 a2, [.LCPI39_0]
 ; GENERIC-NEXT:    jsr16 a2
 ; GENERIC-NEXT:    addi16 sp, sp, 4
 ; GENERIC-NEXT:    ld32.w lr, (sp, 0) # 4-byte Folded Reload
@@ -995,7 +1023,7 @@
 ; GENERIC-NEXT:    .p2align 1
 ; GENERIC-NEXT:  # %bb.1:
 ; GENERIC-NEXT:    .p2align 2, 0x0
-; GENERIC-NEXT:  .LCPI38_0:
+; GENERIC-NEXT:  .LCPI39_0:
 ; GENERIC-NEXT:    .long __divsi3
 entry:
   %sdiv = sdiv  i32 %x, 4097
@@ -1020,7 +1048,7 @@
 ; GENERIC-NEXT:    .cfi_def_cfa_offset 8
 ; GENERIC-NEXT:    sexth16 a2, a1
 ; GENERIC-NEXT:    sexth16 a1, a0
-; GENERIC-NEXT:    lrw32 a3, [.LCPI39_0]
+; GENERIC-NEXT:    lrw32 a3, [.LCPI40_0]
 ; GENERIC-NEXT:    mov16 a0, a2
 ; GENERIC-NEXT:    jsr16 a3
 ; GENERIC-NEXT:    addi16 sp, sp, 4
@@ -1030,7 +1058,7 @@
 ; GENERIC-NEXT:    .p2align 1
 ; GENERIC-NEXT:  # %bb.1:
 ; GENERIC-NEXT:    .p2align 2, 0x0
-; GENERIC-NEXT:  .LCPI39_0:
+; GENERIC-NEXT:  .LCPI40_0:
 ; GENERIC-NEXT:    .long __divsi3
 entry:
   %sdiv = sdiv  i16 %y, %x
@@ -1092,7 +1120,7 @@
 ; GENERIC-NEXT:    .cfi_def_cfa_offset 8
 ; GENERIC-NEXT:    sextb16 a2, a1
 ; GENERIC-NEXT:    sextb16 a1, a0
-; GENERIC-NEXT:    lrw32 a3, [.LCPI41_0]
+; GENERIC-NEXT:    lrw32 a3, [.LCPI42_0]
 ; GENERIC-NEXT:    mov16 a0, a2
 ; GENERIC-NEXT:    jsr16 a3
 ; GENERIC-NEXT:    addi16 sp, sp, 4
@@ -1102,7 +1130,7 @@
 ; GENERIC-NEXT:    .p2align 1
 ; GENERIC-NEXT:  # %bb.1:
 ; GENERIC-NEXT:    .p2align 2, 0x0
-; GENERIC-NEXT:  .LCPI41_0:
+; GENERIC-NEXT:  .LCPI42_0:
 ; GENERIC-NEXT:    .long __divsi3
 entry:
   %sdiv = sdiv  i8 %y, %x
diff --git a/llvm/test/CodeGen/CSKY/switch.ll b/llvm/test/CodeGen/CSKY/switch.ll
--- a/llvm/test/CodeGen/CSKY/switch.ll
+++ b/llvm/test/CodeGen/CSKY/switch.ll
@@ -17,8 +17,7 @@
 ; CHECK-NEXT:    movi16 a0, 0
 ; CHECK-NEXT:    rts16
 ; CHECK-NEXT:  .LBB0_3: # %otherwise
-; CHECK-NEXT:    movih32 a0, 65535
-; CHECK-NEXT:    ori32 a0, a0, 65535
+; CHECK-NEXT:    bmaski32 a0, 32
 ; CHECK-NEXT:    rts16
 ; CHECK-NEXT:  .LBB0_4: # %onone
 ; CHECK-NEXT:    movi16 a0, 1
@@ -34,7 +33,7 @@
 ; CHECK-NEXT:    rts16
 ; CHECK-NEXT:    .p2align 1
 ; CHECK-NEXT:  # %bb.8:
-; CHECK-NEXT:    .p2align 2
+; CHECK-NEXT:    .p2align 2, 0x0
 ; CHECK-NEXT:  .LCPI0_0:
 ; CHECK-NEXT:    .long .LJTI0_0
 ;
@@ -59,8 +58,7 @@
 ; CHECK-PIC-SMALL-NEXT:    movi16 a0, 0
 ; CHECK-PIC-SMALL-NEXT:    br32 .LBB0_8
 ; CHECK-PIC-SMALL-NEXT:  .LBB0_3: # %otherwise
-; CHECK-PIC-SMALL-NEXT:    movih32 a0, 65535
-; CHECK-PIC-SMALL-NEXT:    ori32 a0, a0, 65535
+; CHECK-PIC-SMALL-NEXT:    bmaski32 a0, 32
 ; CHECK-PIC-SMALL-NEXT:    br32 .LBB0_8
 ; CHECK-PIC-SMALL-NEXT:  .LBB0_4: # %onone
 ; CHECK-PIC-SMALL-NEXT:    movi16 a0, 1
@@ -79,7 +77,7 @@
 ; CHECK-PIC-SMALL-NEXT:    rts16
 ; CHECK-PIC-SMALL-NEXT:    .p2align 1
 ; CHECK-PIC-SMALL-NEXT:  # %bb.9:
-; CHECK-PIC-SMALL-NEXT:    .p2align 2
+; CHECK-PIC-SMALL-NEXT:    .p2align 2, 0x0
 ; CHECK-PIC-SMALL-NEXT:  .LCPI0_0:
 ; CHECK-PIC-SMALL-NEXT:    .long _GLOBAL_OFFSET_TABLE_
 ; CHECK-PIC-SMALL-NEXT:  .LCPI0_1:
@@ -106,8 +104,7 @@
 ; CHECK-PIC-LARGE-NEXT:    movi16 a0, 0
 ; CHECK-PIC-LARGE-NEXT:    br32 .LBB0_8
 ; CHECK-PIC-LARGE-NEXT:  .LBB0_3: # %otherwise
-; CHECK-PIC-LARGE-NEXT:    movih32 a0, 65535
-; CHECK-PIC-LARGE-NEXT:    ori32 a0, a0, 65535
+; CHECK-PIC-LARGE-NEXT:    bmaski32 a0, 32
 ; CHECK-PIC-LARGE-NEXT:    br32 .LBB0_8
 ; CHECK-PIC-LARGE-NEXT:  .LBB0_4: # %onone
 ; CHECK-PIC-LARGE-NEXT:    movi16 a0, 1
@@ -126,7 +123,7 @@
 ; CHECK-PIC-LARGE-NEXT:    rts16
 ; CHECK-PIC-LARGE-NEXT:    .p2align 1
 ; CHECK-PIC-LARGE-NEXT:  # %bb.9:
-; CHECK-PIC-LARGE-NEXT:    .p2align 2
+; CHECK-PIC-LARGE-NEXT:    .p2align 2, 0x0
 ; CHECK-PIC-LARGE-NEXT:  .LCPI0_0:
 ; CHECK-PIC-LARGE-NEXT:    .long _GLOBAL_OFFSET_TABLE_
 ; CHECK-PIC-LARGE-NEXT:  .LCPI0_1: