Index: llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.cpp
===================================================================
--- llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.cpp
+++ llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.cpp
@@ -2199,6 +2199,7 @@
   {ARM::tSUBSi8, ARM::tSUBi8},
   {ARM::tSUBSrr, ARM::tSUBrr},
   {ARM::tSBCS, ARM::tSBC},
+  {ARM::tRSBS, ARM::tRSB},
 
   {ARM::t2ADDSri, ARM::t2ADDri},
   {ARM::t2ADDSrr, ARM::t2ADDrr},
Index: llvm/trunk/lib/Target/ARM/ARMInstrThumb.td
===================================================================
--- llvm/trunk/lib/Target/ARM/ARMInstrThumb.td
+++ llvm/trunk/lib/Target/ARM/ARMInstrThumb.td
@@ -1343,6 +1343,12 @@
                                                            tGPR:$Rm))]>,
                 Requires<[IsThumb1Only]>,
                 Sched<[WriteALU]>;
+
+  def tRSBS   : tPseudoInst<(outs tGPR:$Rd), (ins tGPR:$Rn),
+                            2, IIC_iALUr,
+                            [(set tGPR:$Rd, CPSR, (ARMsubc 0, tGPR:$Rn))]>,
+                Requires<[IsThumb1Only]>,
+                Sched<[WriteALU]>;
 }
 
 // Sign-extend byte
Index: llvm/trunk/test/CodeGen/ARM/and-load-combine.ll
===================================================================
--- llvm/trunk/test/CodeGen/ARM/and-load-combine.ll
+++ llvm/trunk/test/CodeGen/ARM/and-load-combine.ll
@@ -28,8 +28,7 @@
 ; THUMB1-NEXT:    ldrb r0, [r0]
 ; THUMB1-NEXT:    ldrb r1, [r1]
 ; THUMB1-NEXT:    eors r1, r0
-; THUMB1-NEXT:    movs r0, #0
-; THUMB1-NEXT:    subs r0, r0, r1
+; THUMB1-NEXT:    rsbs r0, r1, #0
 ; THUMB1-NEXT:    adcs r0, r1
 ; THUMB1-NEXT:    bx lr
 ;
@@ -74,8 +73,7 @@
 ; THUMB1-NEXT:    ldrb r0, [r0]
 ; THUMB1-NEXT:    ldrb r1, [r1]
 ; THUMB1-NEXT:    eors r1, r0
-; THUMB1-NEXT:    movs r0, #0
-; THUMB1-NEXT:    subs r0, r0, r1
+; THUMB1-NEXT:    rsbs r0, r1, #0
 ; THUMB1-NEXT:    adcs r0, r1
 ; THUMB1-NEXT:    bx lr
 ;
@@ -121,8 +119,7 @@
 ; THUMB1-NEXT:    ldrb r0, [r0]
 ; THUMB1-NEXT:    ldrb r1, [r1]
 ; THUMB1-NEXT:    eors r1, r0
-; THUMB1-NEXT:    movs r0, #0
-; THUMB1-NEXT:    subs r0, r0, r1
+; THUMB1-NEXT:    rsbs r0, r1, #0
 ; THUMB1-NEXT:    adcs r0, r1
 ; THUMB1-NEXT:    bx lr
 ;
@@ -167,8 +164,7 @@
 ; THUMB1-NEXT:    ldrh r0, [r0]
 ; THUMB1-NEXT:    ldrh r1, [r1]
 ; THUMB1-NEXT:    eors r1, r0
-; THUMB1-NEXT:    movs r0, #0
-; THUMB1-NEXT:    subs r0, r0, r1
+; THUMB1-NEXT:    rsbs r0, r1, #0
 ; THUMB1-NEXT:    adcs r0, r1
 ; THUMB1-NEXT:    bx lr
 ;
@@ -213,8 +209,7 @@
 ; THUMB1-NEXT:    ldrb r0, [r0]
 ; THUMB1-NEXT:    ldrb r1, [r1]
 ; THUMB1-NEXT:    orrs r1, r0
-; THUMB1-NEXT:    movs r0, #0
-; THUMB1-NEXT:    subs r0, r0, r1
+; THUMB1-NEXT:    rsbs r0, r1, #0
 ; THUMB1-NEXT:    adcs r0, r1
 ; THUMB1-NEXT:    bx lr
 ;
@@ -259,8 +254,7 @@
 ; THUMB1-NEXT:    ldrb r0, [r0]
 ; THUMB1-NEXT:    ldrb r1, [r1]
 ; THUMB1-NEXT:    orrs r1, r0
-; THUMB1-NEXT:    movs r0, #0
-; THUMB1-NEXT:    subs r0, r0, r1
+; THUMB1-NEXT:    rsbs r0, r1, #0
 ; THUMB1-NEXT:    adcs r0, r1
 ; THUMB1-NEXT:    bx lr
 ;
@@ -306,8 +300,7 @@
 ; THUMB1-NEXT:    ldrb r0, [r0]
 ; THUMB1-NEXT:    ldrb r1, [r1]
 ; THUMB1-NEXT:    orrs r1, r0
-; THUMB1-NEXT:    movs r0, #0
-; THUMB1-NEXT:    subs r0, r0, r1
+; THUMB1-NEXT:    rsbs r0, r1, #0
 ; THUMB1-NEXT:    adcs r0, r1
 ; THUMB1-NEXT:    bx lr
 ;
@@ -352,8 +345,7 @@
 ; THUMB1-NEXT:    ldrh r0, [r0]
 ; THUMB1-NEXT:    ldrh r1, [r1]
 ; THUMB1-NEXT:    orrs r1, r0
-; THUMB1-NEXT:    movs r0, #0
-; THUMB1-NEXT:    subs r0, r0, r1
+; THUMB1-NEXT:    rsbs r0, r1, #0
 ; THUMB1-NEXT:    adcs r0, r1
 ; THUMB1-NEXT:    bx lr
 ;
@@ -398,8 +390,7 @@
 ; THUMB1-NEXT:    ldrb r1, [r1]
 ; THUMB1-NEXT:    ldrb r2, [r0]
 ; THUMB1-NEXT:    ands r2, r1
-; THUMB1-NEXT:    movs r0, #0
-; THUMB1-NEXT:    subs r0, r0, r2
+; THUMB1-NEXT:    rsbs r0, r2, #0
 ; THUMB1-NEXT:    adcs r0, r2
 ; THUMB1-NEXT:    bx lr
 ;
@@ -444,8 +435,7 @@
 ; THUMB1-NEXT:    ldrb r0, [r0]
 ; THUMB1-NEXT:    ldrb r1, [r1]
 ; THUMB1-NEXT:    ands r1, r0
-; THUMB1-NEXT:    movs r0, #0
-; THUMB1-NEXT:    subs r0, r0, r1
+; THUMB1-NEXT:    rsbs r0, r1, #0
 ; THUMB1-NEXT:    adcs r0, r1
 ; THUMB1-NEXT:    bx lr
 ;
@@ -491,8 +481,7 @@
 ; THUMB1-NEXT:    ldrb r1, [r1]
 ; THUMB1-NEXT:    ldrb r2, [r0]
 ; THUMB1-NEXT:    ands r2, r1
-; THUMB1-NEXT:    movs r0, #0
-; THUMB1-NEXT:    subs r0, r0, r2
+; THUMB1-NEXT:    rsbs r0, r2, #0
 ; THUMB1-NEXT:    adcs r0, r2
 ; THUMB1-NEXT:    bx lr
 ;
@@ -537,8 +526,7 @@
 ; THUMB1-NEXT:    ldrh r1, [r1]
 ; THUMB1-NEXT:    ldrh r2, [r0]
 ; THUMB1-NEXT:    ands r2, r1
-; THUMB1-NEXT:    movs r0, #0
-; THUMB1-NEXT:    subs r0, r0, r2
+; THUMB1-NEXT:    rsbs r0, r2, #0
 ; THUMB1-NEXT:    adcs r0, r2
 ; THUMB1-NEXT:    bx lr
 ;
@@ -881,8 +869,7 @@
 ; THUMB1-NEXT:    ands r0, r1
 ; THUMB1-NEXT:    uxtb r1, r2
 ; THUMB1-NEXT:    subs r1, r0, r1
-; THUMB1-NEXT:    movs r0, #0
-; THUMB1-NEXT:    subs r0, r0, r1
+; THUMB1-NEXT:    rsbs r0, r1, #0
 ; THUMB1-NEXT:    adcs r0, r1
 ; THUMB1-NEXT:    bx lr
 ;
@@ -929,8 +916,7 @@
 ; THUMB1-NEXT:    ands r0, r1
 ; THUMB1-NEXT:    uxtb r1, r2
 ; THUMB1-NEXT:    subs r1, r0, r1
-; THUMB1-NEXT:    movs r0, #0
-; THUMB1-NEXT:    subs r0, r0, r1
+; THUMB1-NEXT:    rsbs r0, r1, #0
 ; THUMB1-NEXT:    adcs r0, r1
 ; THUMB1-NEXT:    bx lr
 ;
Index: llvm/trunk/test/CodeGen/ARM/atomic-cmpxchg.ll
===================================================================
--- llvm/trunk/test/CodeGen/ARM/atomic-cmpxchg.ll
+++ llvm/trunk/test/CodeGen/ARM/atomic-cmpxchg.ll
@@ -24,8 +24,7 @@
 ; CHECK-THUMB: bl __sync_val_compare_and_swap_1
 ; CHECK-THUMB-NOT: mov [[R1:r[0-7]]], r0
 ; CHECK-THUMB: subs [[R1:r[0-7]]], r0, {{r[0-9]+}}
-; CHECK-THUMB: movs r0, #0
-; CHECK-THUMB: subs r0, r0, [[R1]]
+; CHECK-THUMB: rsbs r0, [[R1]], #0
 ; CHECK-THUMB: adcs r0, [[R1]]
 
 ; CHECK-ARMV6-LABEL: test_cmpxchg_res_i8:
@@ -47,8 +46,7 @@
 ; CHECK-THUMBV6-NEXT:  bl __sync_val_compare_and_swap_1
 ; CHECK-THUMBV6-NEXT:  uxtb r1, r4
 ; CHECK-THUMBV6-NEXT:  subs [[R1:r[0-7]]], r0, {{r[0-9]+}}
-; CHECK-THUMBV6-NEXT:  movs r0, #0
-; CHECK-THUMBV6-NEXT:  subs r0, r0, [[R1]]
+; CHECK-THUMBV6-NEXT:  rsbs r0, [[R1]], #0
 ; CHECK-THUMBV6-NEXT:  adcs r0, [[R1]]
 
 ; CHECK-ARMV7-LABEL: test_cmpxchg_res_i8:
Index: llvm/trunk/test/CodeGen/ARM/select-imm.ll
===================================================================
--- llvm/trunk/test/CodeGen/ARM/select-imm.ll
+++ llvm/trunk/test/CodeGen/ARM/select-imm.ll
@@ -71,8 +71,7 @@
 ; ARMT2: lsr r0, r0, #5
 
 ; THUMB1-LABEL: t3:
-; THUMB1: movs r1, #0
-; THUMB1: subs r1, r1, r0
+; THUMB1: rsbs r1, r0, #0
 ; THUMB1: adcs r0, r1
 
 ; THUMB2-LABEL: t3:
@@ -116,8 +115,7 @@
 
 ; THUMB1-LABEL: t5:
 ; THUMB1-NOT: bne
-; THUMB1: movs r0, #0
-; THUMB1: subs r0, r0, r1
+; THUMB1: rsbs r0, r1, #0
 ; THUMB1: adcs r0, r1
 
 ; THUMB2-LABEL: t5:
@@ -196,8 +194,7 @@
 ; THUMB1: bl t7
 ; THUMB1: mov r1, r0
 ; THUMB1: subs r2, r4, #5
-; THUMB1: movs r0, #0
-; THUMB1: subs r0, r0, r2
+; THUMB1: rsbs r0, r2, #0
 ; THUMB1: adcs r0, r2
 
 ; THUMB2-LABEL: t8:
@@ -302,8 +299,7 @@
 ; ARMT2: lsr r0, r0, #5
 
 ; THUMB1-LABEL: t10:
-; THUMB1: movs r0, #0
-; THUMB1: subs r0, r0, r1
+; THUMB1: rsbs r0, r1, #0
 ; THUMB1: adcs r0, r1
 
 ; THUMB2-LABEL: t10:
Index: llvm/trunk/test/CodeGen/ARM/smml.ll
===================================================================
--- llvm/trunk/test/CodeGen/ARM/smml.ll
+++ llvm/trunk/test/CodeGen/ARM/smml.ll
@@ -44,7 +44,7 @@
 define void @test_used_flags(i32 %in1, i32 %in2) {
 ; CHECK-LABEL: test_used_flags:
 ; CHECK-THUMB: movs    r2, #0
-; CHECK-THUMB: subs    r0, r2, r0
+; CHECK-THUMB: rsbs    r0, r0, #0
 ; CHECK-THUMB: sbcs    r2, r1
 ; CHECK-THUMB: bge
 ; CHECK-V6: smull [[PROD_LO:r[0-9]+]], [[PROD_HI:r[0-9]+]], r0, r1
Index: llvm/trunk/test/CodeGen/Thumb/branchless-cmp.ll
===================================================================
--- llvm/trunk/test/CodeGen/Thumb/branchless-cmp.ll
+++ llvm/trunk/test/CodeGen/Thumb/branchless-cmp.ll
@@ -20,8 +20,7 @@
 ; CHECK-LABEL: test1b:
 ; CHECK-NOT: b{{(ne)|(eq)}}
 ; CHECK:       subs    r1, r0, r1
-; CHECK-NEXT:  movs    r0, #0
-; CHECK-NEXT:  subs    r0, r0, r1
+; CHECK-NEXT:  rsbs    r0, r1, #0
 ; CHECK-NEXT:  adcs    r0, r1
 }
 
@@ -33,8 +32,7 @@
 ; CHECK-LABEL: test2a:
 ; CHECK-NOT: b{{(ne)|(eq)}}
 ; CHECK:       subs    r1, r0, r1
-; CHECK-NEXT:  movs    r0, #0
-; CHECK-NEXT:  subs    r0, r0, r1
+; CHECK-NEXT:  rsbs    r0, r1, #0
 ; CHECK-NEXT:  adcs    r0, r1
 }
 
@@ -71,8 +69,7 @@
 ; CHECK-LABEL: test3b:
 ; CHECK-NOT: b{{(ne)|(eq)}}
 ; CHECK:      subs	r0, r0, r1
-; CHECK-NEXT: movs	r1, #0
-; CHECK-NEXT: subs	r1, r1, r0
+; CHECK-NEXT: rsbs	r1, r0, #0
 ; CHECK-NEXT: adcs	r1, r0
 ; CHECK-NEXT: lsls	r0, r1, #2
 }
Index: llvm/trunk/test/CodeGen/Thumb/long-setcc.ll
===================================================================
--- llvm/trunk/test/CodeGen/Thumb/long-setcc.ll
+++ llvm/trunk/test/CodeGen/Thumb/long-setcc.ll
@@ -9,8 +9,7 @@
 
 define i1 @t2(i64 %x) {
 ; CHECK-LABEL: t2:
-; CHECK: movs  r0, #0
-; CHECK: subs  r0, r0, r1
+; CHECK: rsbs  r0, r1, #0
 ; CHECK: adcs  r0, r1
   %tmp = icmp ult i64 %x, 4294967296
   ret i1 %tmp