Index: lib/Target/X86/X86ISelDAGToDAG.cpp
===================================================================
--- lib/Target/X86/X86ISelDAGToDAG.cpp
+++ lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -2064,8 +2064,8 @@
                   Segment))
     return false;
 
-  auto SelectOpcodeForSize = [&](unsigned Opc64, unsigned Opc32, unsigned Opc16,
-                                 unsigned Opc8) {
+  auto SelectOpcode = [&](unsigned Opc64, unsigned Opc32, unsigned Opc16,
+                                 unsigned Opc8 = 0) {
     switch (MemVT.getSimpleVT().SimpleTy) {
     case MVT::i64:
       return Opc64;
@@ -2084,11 +2084,10 @@
   switch (Opc) {
   case X86ISD::INC:
   case X86ISD::DEC: {
-    unsigned NewOpc = Opc == X86ISD::INC
-                          ? SelectOpcodeForSize(X86::INC64m, X86::INC32m,
-                                                X86::INC16m, X86::INC8m)
-                          : SelectOpcodeForSize(X86::DEC64m, X86::DEC32m,
-                                                X86::DEC16m, X86::DEC8m);
+    unsigned NewOpc =
+        Opc == X86ISD::INC
+            ? SelectOpcode(X86::INC64m, X86::INC32m, X86::INC16m, X86::INC8m)
+            : SelectOpcode(X86::DEC64m, X86::DEC32m, X86::DEC16m, X86::DEC8m);
     const SDValue Ops[] = {Base, Scale, Index, Disp, Segment, InputChain};
     Result =
         CurDAG->getMachineNode(NewOpc, SDLoc(Node), MVT::i32, MVT::Other, Ops);
@@ -2096,14 +2095,77 @@
   }
   case X86ISD::ADD:
   case X86ISD::SUB: {
-    unsigned NewOpc = Opc == X86ISD::ADD
-                          ? SelectOpcodeForSize(X86::ADD64mr, X86::ADD32mr,
-                                                X86::ADD16mr, X86::ADD8mr)
-                          : SelectOpcodeForSize(X86::SUB64mr, X86::SUB32mr,
-                                                X86::SUB16mr, X86::SUB8mr);
-    const SDValue Ops[] = {Base,      Scale,   Index,
-                           Disp,      Segment, StoredVal->getOperand(1),
-                           InputChain};
+    auto SelectRegOpcode = [SelectOpcode](unsigned Opc) {
+      switch (Opc) {
+      case X86ISD::ADD:
+        return SelectOpcode(X86::ADD64mr, X86::ADD32mr, X86::ADD16mr,
+                            X86::ADD8mr);
+      case X86ISD::SUB:
+        return SelectOpcode(X86::SUB64mr, X86::SUB32mr, X86::SUB16mr,
+                            X86::SUB8mr);
+      default:
+        llvm_unreachable("Invalid opcode!");
+      }
+    };
+    auto SelectImm8Opcode = [SelectOpcode](unsigned Opc) {
+      switch (Opc) {
+      case X86ISD::ADD:
+        return SelectOpcode(X86::ADD64mi8, X86::ADD32mi8, X86::ADD16mi8);
+      case X86ISD::SUB:
+        return SelectOpcode(X86::SUB64mi8, X86::SUB32mi8, X86::SUB16mi8);
+      default:
+        llvm_unreachable("Invalid opcode!");
+      }
+    };
+    auto SelectImmOpcode = [SelectOpcode](unsigned Opc) {
+      switch (Opc) {
+      case X86ISD::ADD:
+        return SelectOpcode(X86::ADD64mi32, X86::ADD32mi, X86::ADD16mi,
+                            X86::ADD8mi);
+      case X86ISD::SUB:
+        return SelectOpcode(X86::SUB64mi32, X86::SUB32mi, X86::SUB16mi,
+                            X86::SUB8mi);
+      default:
+        llvm_unreachable("Invalid opcode!");
+      }
+    };
+
+    unsigned NewOpc = SelectRegOpcode(Opc);
+    SDValue Operand = StoredVal->getOperand(1);
+
+    // See if the operand is a constant that we can fold into an immediate
+    // operand.
+    if (auto *OperandC = dyn_cast<ConstantSDNode>(Operand)) {
+      auto OperandV = OperandC->getAPIntValue();
+
+      // Check if we can shrink the operand enough to fit in an immediate (or
+      // fit into a smaller immediate) by negating it and switching the
+      // operation.
+      if ((MemVT != MVT::i8 && OperandV.getMinSignedBits() > 8 &&
+           (-OperandV).getMinSignedBits() <= 8) ||
+          (MemVT == MVT::i64 && OperandV.getMinSignedBits() > 32 &&
+           (-OperandV).getMinSignedBits() <= 32)) {
+        OperandV = -OperandV;
+        Opc = Opc == X86ISD::ADD ? X86ISD::SUB : X86ISD::ADD;
+      }
+
+      // First try to fit this into an Imm8 operand. If it doesn't fit, then try the larger immediate operand.
+      if (MemVT != MVT::i8 && OperandV.getMinSignedBits() <= 8) {
+        Operand =
+            CurDAG->getTargetConstant(OperandV.trunc(8), SDLoc(Node), MVT::i8);
+        NewOpc = SelectImm8Opcode(Opc);
+      } else if (OperandV.getActiveBits() <= MemVT.getSizeInBits() &&
+                 (MemVT != MVT::i64 || OperandV.getMinSignedBits() <= 32)) {
+        MVT ImmVT = MemVT == MVT::i64 ? MVT::i32 : MemVT.getSimpleVT();
+        if (MemVT == MVT::i64)
+          OperandV = OperandV.trunc(32);
+        Operand = CurDAG->getTargetConstant(OperandV, SDLoc(Node), ImmVT);
+        NewOpc = SelectImmOpcode(Opc);
+      }
+    }
+
+    const SDValue Ops[] = {Base,    Scale,   Index,     Disp,
+                           Segment, Operand, InputChain};
     Result =
         CurDAG->getMachineNode(NewOpc, SDLoc(Node), MVT::i32, MVT::Other, Ops);
     break;
Index: test/CodeGen/X86/add.ll
===================================================================
--- test/CodeGen/X86/add.ll
+++ test/CodeGen/X86/add.ll
@@ -340,8 +340,7 @@
 define void @test12(i64* inreg %a) nounwind {
 ; X32-LABEL: test12:
 ; X32:       # BB#0: # %entry
-; X32-NEXT:    movl $-2147483648, %ecx # imm = 0x80000000
-; X32-NEXT:    addl %ecx, (%eax)
+; X32-NEXT:    addl $-2147483648, (%eax) # imm = 0x80000000
 ; X32-NEXT:    adcl $0, 4(%eax)
 ; X32-NEXT:    retl
 ;
@@ -364,8 +363,7 @@
 define void @test13(i64* inreg %a) nounwind {
 ; X32-LABEL: test13:
 ; X32:       # BB#0: # %entry
-; X32-NEXT:    movl $128, %ecx
-; X32-NEXT:    addl %ecx, (%eax)
+; X32-NEXT:    subl $-128, (%eax)
 ; X32-NEXT:    adcl $0, 4(%eax)
 ; X32-NEXT:    retl
 ;
Index: test/CodeGen/X86/fold-rmw-ops.ll
===================================================================
--- test/CodeGen/X86/fold-rmw-ops.ll
+++ test/CodeGen/X86/fold-rmw-ops.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
-; RUN: llc < %s -verify-machineinstrs | FileCheck %s
+; RUN: llc < %s -verify-machineinstrs -show-mc-encoding | FileCheck %s
 
 target triple = "x86_64-unknown-unknown"
 
@@ -11,19 +11,188 @@
 declare void @a()
 declare void @b()
 
-define void @add64_imm_br() nounwind {
-; CHECK-LABEL: add64_imm_br:
+define void @add64_imm32_br() nounwind {
+; CHECK-LABEL: add64_imm32_br:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    movl $42, %eax
-; CHECK-NEXT:    addq %rax, {{.*}}(%rip)
-; CHECK-NEXT:    js .LBB0_1
+; CHECK-NEXT:    addq $16777214, {{.*}}(%rip) # encoding: [0x48,0x81,0x05,A,A,A,A,0xfe,0xff,0xff,0x00]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g64-8, kind: reloc_riprel_4byte
+; CHECK-NEXT:    # imm = 0xFFFFFE
+; CHECK-NEXT:    js .LBB0_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB0_1-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  # BB#2: # %b
 ; CHECK-NEXT:    jmp b # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  .LBB0_1: # %a
 ; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
 entry:
   %load1 = load i64, i64* @g64
-  %add = add nsw i64 %load1, 42
+  ; Add 0x00FFFFFE, a positive immediate requiring 24-bits.
+  %add = add i64 %load1, 16777214
+  store i64 %add, i64* @g64
+  %cond = icmp slt i64 %add, 0
+  br i1 %cond, label %a, label %b
+
+a:
+  tail call void @a()
+  ret void
+
+b:
+  tail call void @b()
+  ret void
+}
+
+define void @add64_sext_imm32_br() nounwind {
+; CHECK-LABEL: add64_sext_imm32_br:
+; CHECK:       # BB#0: # %entry
+; CHECK-NEXT:    addq $-2147483648, {{.*}}(%rip) # encoding: [0x48,0x81,0x05,A,A,A,A,0x00,0x00,0x00,0x80]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g64-8, kind: reloc_riprel_4byte
+; CHECK-NEXT:    # imm = 0x80000000
+; CHECK-NEXT:    js .LBB1_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB1_1-1, kind: FK_PCRel_1
+; CHECK-NEXT:  # BB#2: # %b
+; CHECK-NEXT:    jmp b # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB1_1: # %a
+; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
+entry:
+  %load1 = load i64, i64* @g64
+  ; Add -0x80000000, which requires sign-extended 32 bits.
+  %add = add i64 %load1, -2147483648
+  store i64 %add, i64* @g64
+  %cond = icmp slt i64 %add, 0
+  br i1 %cond, label %a, label %b
+
+a:
+  tail call void @a()
+  ret void
+
+b:
+  tail call void @b()
+  ret void
+}
+
+define void @add64_too_large_imm32_br() nounwind {
+; CHECK-LABEL: add64_too_large_imm32_br:
+; CHECK:       # BB#0: # %entry
+; CHECK-NEXT:    subq $-2147483648, {{.*}}(%rip) # encoding: [0x48,0x81,0x2d,A,A,A,A,0x00,0x00,0x00,0x80]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g64-8, kind: reloc_riprel_4byte
+; CHECK-NEXT:    # imm = 0x80000000
+; CHECK-NEXT:    js .LBB2_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB2_1-1, kind: FK_PCRel_1
+; CHECK-NEXT:  # BB#2: # %b
+; CHECK-NEXT:    jmp b # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB2_1: # %a
+; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
+entry:
+  %load1 = load i64, i64* @g64
+  ; Add 0x80000000, which cannot fit in a sign extended 32-bit immediate. This
+  ; should *not* get folded into an immediate operand!
+  %add = add i64 %load1, 2147483648
+  store i64 %add, i64* @g64
+  %cond = icmp slt i64 %add, 0
+  br i1 %cond, label %a, label %b
+
+a:
+  tail call void @a()
+  ret void
+
+b:
+  tail call void @b()
+  ret void
+}
+
+define void @add64_imm8_via_sub_br() nounwind {
+; CHECK-LABEL: add64_imm8_via_sub_br:
+; CHECK:       # BB#0: # %entry
+; CHECK-NEXT:    subq $-128, {{.*}}(%rip) # encoding: [0x48,0x83,0x2d,A,A,A,A,0x80]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g64-5, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB3_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB3_1-1, kind: FK_PCRel_1
+; CHECK-NEXT:  # BB#2: # %b
+; CHECK-NEXT:    jmp b # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB3_1: # %a
+; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
+entry:
+  %load1 = load i64, i64* @g64
+  ; Add 0x80 which can't quite fit into an imm8 because it would be sign
+  ; extended, but which can fit if we convert to a sub and negate the value.
+  %add = add i64 %load1, 128
+  store i64 %add, i64* @g64
+  %cond = icmp slt i64 %add, 0
+  br i1 %cond, label %a, label %b
+
+a:
+  tail call void @a()
+  ret void
+
+b:
+  tail call void @b()
+  ret void
+}
+
+define void @add64_imm8_br() nounwind {
+; CHECK-LABEL: add64_imm8_br:
+; CHECK:       # BB#0: # %entry
+; CHECK-NEXT:    addq $42, {{.*}}(%rip) # encoding: [0x48,0x83,0x05,A,A,A,A,0x2a]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g64-5, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB4_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB4_1-1, kind: FK_PCRel_1
+; CHECK-NEXT:  # BB#2: # %b
+; CHECK-NEXT:    jmp b # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB4_1: # %a
+; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
+entry:
+  %load1 = load i64, i64* @g64
+  %add = add i64 %load1, 42
+  store i64 %add, i64* @g64
+  %cond = icmp slt i64 %add, 0
+  br i1 %cond, label %a, label %b
+
+a:
+  tail call void @a()
+  ret void
+
+b:
+  tail call void @b()
+  ret void
+}
+
+define void @add64_imm8_neg_br() nounwind {
+; CHECK-LABEL: add64_imm8_neg_br:
+; CHECK:       # BB#0: # %entry
+; CHECK-NEXT:    addq $-42, {{.*}}(%rip) # encoding: [0x48,0x83,0x05,A,A,A,A,0xd6]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g64-5, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB5_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB5_1-1, kind: FK_PCRel_1
+; CHECK-NEXT:  # BB#2: # %b
+; CHECK-NEXT:    jmp b # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB5_1: # %a
+; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
+entry:
+  %load1 = load i64, i64* @g64
+  %add = add i64 %load1, -42
   store i64 %add, i64* @g64
   %cond = icmp slt i64 %add, 0
   br i1 %cond, label %a, label %b
@@ -40,16 +209,85 @@
 define void @add32_imm_br() nounwind {
 ; CHECK-LABEL: add32_imm_br:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    movl $42, %eax
-; CHECK-NEXT:    addl %eax, {{.*}}(%rip)
-; CHECK-NEXT:    js .LBB1_1
+; CHECK-NEXT:    addl $-2147483648, {{.*}}(%rip) # encoding: [0x81,0x05,A,A,A,A,0x00,0x00,0x00,0x80]
+; CHECK-NEXT:    # fixup A - offset: 2, value: g32-8, kind: reloc_riprel_4byte
+; CHECK-NEXT:    # imm = 0x80000000
+; CHECK-NEXT:    js .LBB6_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB6_1-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  # BB#2: # %b
 ; CHECK-NEXT:    jmp b # TAILCALL
-; CHECK-NEXT:  .LBB1_1: # %a
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB6_1: # %a
 ; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
 entry:
   %load1 = load i32, i32* @g32
-  %add = add nsw i32 %load1, 42
+  ; Add 0x80000000, a positive number requiring 32 bits of immediate.
+  %add = add i32 %load1, 2147483648
+  store i32 %add, i32* @g32
+  %cond = icmp slt i32 %add, 0
+  br i1 %cond, label %a, label %b
+
+a:
+  tail call void @a()
+  ret void
+
+b:
+  tail call void @b()
+  ret void
+}
+
+define void @add32_imm8_br() nounwind {
+; CHECK-LABEL: add32_imm8_br:
+; CHECK:       # BB#0: # %entry
+; CHECK-NEXT:    addl $42, {{.*}}(%rip) # encoding: [0x83,0x05,A,A,A,A,0x2a]
+; CHECK-NEXT:    # fixup A - offset: 2, value: g32-5, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB7_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB7_1-1, kind: FK_PCRel_1
+; CHECK-NEXT:  # BB#2: # %b
+; CHECK-NEXT:    jmp b # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB7_1: # %a
+; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
+entry:
+  %load1 = load i32, i32* @g32
+  %add = add i32 %load1, 42
+  store i32 %add, i32* @g32
+  %cond = icmp slt i32 %add, 0
+  br i1 %cond, label %a, label %b
+
+a:
+  tail call void @a()
+  ret void
+
+b:
+  tail call void @b()
+  ret void
+}
+
+define void @add32_imm8_neg_br() nounwind {
+; CHECK-LABEL: add32_imm8_neg_br:
+; CHECK:       # BB#0: # %entry
+; CHECK-NEXT:    addl $-42, {{.*}}(%rip) # encoding: [0x83,0x05,A,A,A,A,0xd6]
+; CHECK-NEXT:    # fixup A - offset: 2, value: g32-5, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB8_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB8_1-1, kind: FK_PCRel_1
+; CHECK-NEXT:  # BB#2: # %b
+; CHECK-NEXT:    jmp b # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB8_1: # %a
+; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
+entry:
+  %load1 = load i32, i32* @g32
+  %add = add i32 %load1, -42
   store i32 %add, i32* @g32
   %cond = icmp slt i32 %add, 0
   br i1 %cond, label %a, label %b
@@ -66,16 +304,85 @@
 define void @add16_imm_br() nounwind {
 ; CHECK-LABEL: add16_imm_br:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    movw $42, %ax
-; CHECK-NEXT:    addw %ax, {{.*}}(%rip)
-; CHECK-NEXT:    js .LBB2_1
+; CHECK-NEXT:    addw $-32768, {{.*}}(%rip) # encoding: [0x66,0x81,0x05,A,A,A,A,0x00,0x80]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g16-6, kind: reloc_riprel_4byte
+; CHECK-NEXT:    # imm = 0x8000
+; CHECK-NEXT:    js .LBB9_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB9_1-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  # BB#2: # %b
 ; CHECK-NEXT:    jmp b # TAILCALL
-; CHECK-NEXT:  .LBB2_1: # %a
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB9_1: # %a
 ; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
 entry:
   %load1 = load i16, i16* @g16
-  %add = add nsw i16 %load1, 42
+  ; Add 0x8000, a positive number requiring 16 bits of immediate.
+  %add = add i16 %load1, 32768
+  store i16 %add, i16* @g16
+  %cond = icmp slt i16 %add, 0
+  br i1 %cond, label %a, label %b
+
+a:
+  tail call void @a()
+  ret void
+
+b:
+  tail call void @b()
+  ret void
+}
+
+define void @add16_imm8_br() nounwind {
+; CHECK-LABEL: add16_imm8_br:
+; CHECK:       # BB#0: # %entry
+; CHECK-NEXT:    addw $42, {{.*}}(%rip) # encoding: [0x66,0x83,0x05,A,A,A,A,0x2a]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g16-5, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB10_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB10_1-1, kind: FK_PCRel_1
+; CHECK-NEXT:  # BB#2: # %b
+; CHECK-NEXT:    jmp b # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB10_1: # %a
+; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
+entry:
+  %load1 = load i16, i16* @g16
+  %add = add i16 %load1, 42
+  store i16 %add, i16* @g16
+  %cond = icmp slt i16 %add, 0
+  br i1 %cond, label %a, label %b
+
+a:
+  tail call void @a()
+  ret void
+
+b:
+  tail call void @b()
+  ret void
+}
+
+define void @add16_imm8_neg_br() nounwind {
+; CHECK-LABEL: add16_imm8_neg_br:
+; CHECK:       # BB#0: # %entry
+; CHECK-NEXT:    addw $-42, {{.*}}(%rip) # encoding: [0x66,0x83,0x05,A,A,A,A,0xd6]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g16-5, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB11_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB11_1-1, kind: FK_PCRel_1
+; CHECK-NEXT:  # BB#2: # %b
+; CHECK-NEXT:    jmp b # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB11_1: # %a
+; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
+entry:
+  %load1 = load i16, i16* @g16
+  %add = add i16 %load1, -42
   store i16 %add, i16* @g16
   %cond = icmp slt i16 %add, 0
   br i1 %cond, label %a, label %b
@@ -92,16 +399,21 @@
 define void @add8_imm_br() nounwind {
 ; CHECK-LABEL: add8_imm_br:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    movb $42, %al
-; CHECK-NEXT:    addb %al, {{.*}}(%rip)
-; CHECK-NEXT:    js .LBB3_1
+; CHECK-NEXT:    addb $-2, {{.*}}(%rip) # encoding: [0x80,0x05,A,A,A,A,0xfe]
+; CHECK-NEXT:    # fixup A - offset: 2, value: g8-5, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB12_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB12_1-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  # BB#2: # %b
 ; CHECK-NEXT:    jmp b # TAILCALL
-; CHECK-NEXT:  .LBB3_1: # %a
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB12_1: # %a
 ; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
 entry:
   %load1 = load i8, i8* @g8
-  %add = add nsw i8 %load1, 42
+  %add = add i8 %load1, -2
   store i8 %add, i8* @g8
   %cond = icmp slt i8 %add, 0
   br i1 %cond, label %a, label %b
@@ -118,15 +430,21 @@
 define void @add64_reg_br(i64 %arg) nounwind {
 ; CHECK-LABEL: add64_reg_br:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    addq %rdi, {{.*}}(%rip)
-; CHECK-NEXT:    js .LBB4_1
+; CHECK-NEXT:    addq %rdi, {{.*}}(%rip) # encoding: [0x48,0x01,0x3d,A,A,A,A]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g64-4, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB13_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB13_1-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  # BB#2: # %b
 ; CHECK-NEXT:    jmp b # TAILCALL
-; CHECK-NEXT:  .LBB4_1: # %a
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB13_1: # %a
 ; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
 entry:
   %load1 = load i64, i64* @g64
-  %add = add nsw i64 %load1, %arg
+  %add = add i64 %load1, %arg
   store i64 %add, i64* @g64
   %cond = icmp slt i64 %add, 0
   br i1 %cond, label %a, label %b
@@ -143,15 +461,21 @@
 define void @add32_reg_br(i32 %arg) nounwind {
 ; CHECK-LABEL: add32_reg_br:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    addl %edi, {{.*}}(%rip)
-; CHECK-NEXT:    js .LBB5_1
+; CHECK-NEXT:    addl %edi, {{.*}}(%rip) # encoding: [0x01,0x3d,A,A,A,A]
+; CHECK-NEXT:    # fixup A - offset: 2, value: g32-4, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB14_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB14_1-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  # BB#2: # %b
 ; CHECK-NEXT:    jmp b # TAILCALL
-; CHECK-NEXT:  .LBB5_1: # %a
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB14_1: # %a
 ; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
 entry:
   %load1 = load i32, i32* @g32
-  %add = add nsw i32 %load1, %arg
+  %add = add i32 %load1, %arg
   store i32 %add, i32* @g32
   %cond = icmp slt i32 %add, 0
   br i1 %cond, label %a, label %b
@@ -168,15 +492,21 @@
 define void @add16_reg_br(i16 %arg) nounwind {
 ; CHECK-LABEL: add16_reg_br:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    addw %di, {{.*}}(%rip)
-; CHECK-NEXT:    js .LBB6_1
+; CHECK-NEXT:    addw %di, {{.*}}(%rip) # encoding: [0x66,0x01,0x3d,A,A,A,A]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g16-4, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB15_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB15_1-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  # BB#2: # %b
 ; CHECK-NEXT:    jmp b # TAILCALL
-; CHECK-NEXT:  .LBB6_1: # %a
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB15_1: # %a
 ; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
 entry:
   %load1 = load i16, i16* @g16
-  %add = add nsw i16 %load1, %arg
+  %add = add i16 %load1, %arg
   store i16 %add, i16* @g16
   %cond = icmp slt i16 %add, 0
   br i1 %cond, label %a, label %b
@@ -193,15 +523,21 @@
 define void @add8_reg_br(i8 %arg) nounwind {
 ; CHECK-LABEL: add8_reg_br:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    addb %dil, {{.*}}(%rip)
-; CHECK-NEXT:    js .LBB7_1
+; CHECK-NEXT:    addb %dil, {{.*}}(%rip) # encoding: [0x40,0x00,0x3d,A,A,A,A]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g8-4, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB16_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB16_1-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  # BB#2: # %b
 ; CHECK-NEXT:    jmp b # TAILCALL
-; CHECK-NEXT:  .LBB7_1: # %a
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB16_1: # %a
 ; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
 entry:
   %load1 = load i8, i8* @g8
-  %add = add nsw i8 %load1, %arg
+  %add = add i8 %load1, %arg
   store i8 %add, i8* @g8
   %cond = icmp slt i8 %add, 0
   br i1 %cond, label %a, label %b
@@ -215,19 +551,95 @@
   ret void
 }
 
-define void @sub64_imm_br() nounwind {
-; CHECK-LABEL: sub64_imm_br:
+define void @sub64_imm32_br() nounwind {
+; CHECK-LABEL: sub64_imm32_br:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    movq $-42, %rax
-; CHECK-NEXT:    addq %rax, {{.*}}(%rip)
-; CHECK-NEXT:    js .LBB8_1
+; CHECK-NEXT:    subq $-2147483648, {{.*}}(%rip) # encoding: [0x48,0x81,0x2d,A,A,A,A,0x00,0x00,0x00,0x80]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g64-8, kind: reloc_riprel_4byte
+; CHECK-NEXT:    # imm = 0x80000000
+; CHECK-NEXT:    js .LBB17_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB17_1-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  # BB#2: # %b
 ; CHECK-NEXT:    jmp b # TAILCALL
-; CHECK-NEXT:  .LBB8_1: # %a
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB17_1: # %a
+; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
+entry:
+  %load1 = load i64, i64* @g64
+  ; Subtract -0x80000000, which can't be negated into a sign-extended 32-bit
+  ; immediate, so that we have to select sub here.
+  %sub = sub i64 %load1, -2147483648
+  store i64 %sub, i64* @g64
+  %cond = icmp slt i64 %sub, 0
+  br i1 %cond, label %a, label %b
+
+a:
+  tail call void @a()
+  ret void
+
+b:
+  tail call void @b()
+  ret void
+}
+
+define void @sub64_too_large_imm32_br() nounwind {
+; CHECK-LABEL: sub64_too_large_imm32_br:
+; CHECK:       # BB#0: # %entry
+; CHECK-NEXT:    movabsq $-4294967295, %rax # encoding: [0x48,0xb8,0x01,0x00,0x00,0x00,0xff,0xff,0xff,0xff]
+; CHECK-NEXT:    # imm = 0xFFFFFFFF00000001
+; CHECK-NEXT:    addq %rax, {{.*}}(%rip) # encoding: [0x48,0x01,0x05,A,A,A,A]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g64-4, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB18_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB18_1-1, kind: FK_PCRel_1
+; CHECK-NEXT:  # BB#2: # %b
+; CHECK-NEXT:    jmp b # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB18_1: # %a
 ; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
 entry:
   %load1 = load i64, i64* @g64
-  %sub = sub nsw i64 %load1, 42
+  ; Subtract 0xFFFFFFFF, which cannot fit in a sign extended 32-bit immediate,
+  ; even if negated and sign extended as an add.
+  %sub = sub i64 %load1, 4294967295
+  store i64 %sub, i64* @g64
+  %cond = icmp slt i64 %sub, 0
+  br i1 %cond, label %a, label %b
+
+a:
+  tail call void @a()
+  ret void
+
+b:
+  tail call void @b()
+  ret void
+}
+
+define void @sub64_imm8_br() nounwind {
+; CHECK-LABEL: sub64_imm8_br:
+; CHECK:       # BB#0: # %entry
+; CHECK-NEXT:    subq $-128, {{.*}}(%rip) # encoding: [0x48,0x83,0x2d,A,A,A,A,0x80]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g64-5, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB19_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB19_1-1, kind: FK_PCRel_1
+; CHECK-NEXT:  # BB#2: # %b
+; CHECK-NEXT:    jmp b # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB19_1: # %a
+; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
+entry:
+  %load1 = load i64, i64* @g64
+  ; Subtract -0x80, which can be done with an 8-bit immediate but only as
+  ; a subtract where that immediate can be negative.
+  %sub = sub i64 %load1, -128
   store i64 %sub, i64* @g64
   %cond = icmp slt i64 %sub, 0
   br i1 %cond, label %a, label %b
@@ -244,16 +656,57 @@
 define void @sub32_imm_br() nounwind {
 ; CHECK-LABEL: sub32_imm_br:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    movl $-42, %eax
-; CHECK-NEXT:    addl %eax, {{.*}}(%rip)
-; CHECK-NEXT:    js .LBB9_1
+; CHECK-NEXT:    addl $-2147483648, {{.*}}(%rip) # encoding: [0x81,0x05,A,A,A,A,0x00,0x00,0x00,0x80]
+; CHECK-NEXT:    # fixup A - offset: 2, value: g32-8, kind: reloc_riprel_4byte
+; CHECK-NEXT:    # imm = 0x80000000
+; CHECK-NEXT:    js .LBB20_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB20_1-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  # BB#2: # %b
 ; CHECK-NEXT:    jmp b # TAILCALL
-; CHECK-NEXT:  .LBB9_1: # %a
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB20_1: # %a
 ; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
 entry:
   %load1 = load i32, i32* @g32
-  %sub = sub nsw i32 %load1, 42
+  ; Subtract -0x80000000, which requires 32 bits of immediate but still gets
+  ; lowered as an add.
+  %sub = sub i32 %load1, -2147483648
+  store i32 %sub, i32* @g32
+  %cond = icmp slt i32 %sub, 0
+  br i1 %cond, label %a, label %b
+
+a:
+  tail call void @a()
+  ret void
+
+b:
+  tail call void @b()
+  ret void
+}
+
+define void @sub32_imm8_br() nounwind {
+; CHECK-LABEL: sub32_imm8_br:
+; CHECK:       # BB#0: # %entry
+; CHECK-NEXT:    subl $-128, {{.*}}(%rip) # encoding: [0x83,0x2d,A,A,A,A,0x80]
+; CHECK-NEXT:    # fixup A - offset: 2, value: g32-5, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB21_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB21_1-1, kind: FK_PCRel_1
+; CHECK-NEXT:  # BB#2: # %b
+; CHECK-NEXT:    jmp b # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB21_1: # %a
+; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
+entry:
+  %load1 = load i32, i32* @g32
+  ; Subtract -0x80, which can be done with an 8-bit immediate but only as
+  ; a subtract where that immediate can be negative.
+  %sub = sub i32 %load1, -128
   store i32 %sub, i32* @g32
   %cond = icmp slt i32 %sub, 0
   br i1 %cond, label %a, label %b
@@ -270,16 +723,57 @@
 define void @sub16_imm_br() nounwind {
 ; CHECK-LABEL: sub16_imm_br:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    movw $-42, %ax
-; CHECK-NEXT:    addw %ax, {{.*}}(%rip)
-; CHECK-NEXT:    js .LBB10_1
+; CHECK-NEXT:    addw $-32768, {{.*}}(%rip) # encoding: [0x66,0x81,0x05,A,A,A,A,0x00,0x80]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g16-6, kind: reloc_riprel_4byte
+; CHECK-NEXT:    # imm = 0x8000
+; CHECK-NEXT:    js .LBB22_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB22_1-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  # BB#2: # %b
 ; CHECK-NEXT:    jmp b # TAILCALL
-; CHECK-NEXT:  .LBB10_1: # %a
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB22_1: # %a
+; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
+entry:
+  %load1 = load i16, i16* @g16
+  ; Subtract -0x8000, which requires a 16 bits of immediate but still gets
+  ; lowered as an add.
+  %sub = sub i16 %load1, -32768
+  store i16 %sub, i16* @g16
+  %cond = icmp slt i16 %sub, 0
+  br i1 %cond, label %a, label %b
+
+a:
+  tail call void @a()
+  ret void
+
+b:
+  tail call void @b()
+  ret void
+}
+
+define void @sub16_imm8_br() nounwind {
+; CHECK-LABEL: sub16_imm8_br:
+; CHECK:       # BB#0: # %entry
+; CHECK-NEXT:    subw $-128, {{.*}}(%rip) # encoding: [0x66,0x83,0x2d,A,A,A,A,0x80]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g16-5, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB23_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB23_1-1, kind: FK_PCRel_1
+; CHECK-NEXT:  # BB#2: # %b
+; CHECK-NEXT:    jmp b # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB23_1: # %a
 ; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
 entry:
   %load1 = load i16, i16* @g16
-  %sub = sub nsw i16 %load1, 42
+  ; Subtract -0x80, which can be done with an 8-bit immediate but only as
+  ; a subtract where that immediate can be negative.
+  %sub = sub i16 %load1, -128
   store i16 %sub, i16* @g16
   %cond = icmp slt i16 %sub, 0
   br i1 %cond, label %a, label %b
@@ -296,16 +790,23 @@
 define void @sub8_imm_br() nounwind {
 ; CHECK-LABEL: sub8_imm_br:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    movb $-42, %al
-; CHECK-NEXT:    addb %al, {{.*}}(%rip)
-; CHECK-NEXT:    js .LBB11_1
+; CHECK-NEXT:    addb $-128, {{.*}}(%rip) # encoding: [0x80,0x05,A,A,A,A,0x80]
+; CHECK-NEXT:    # fixup A - offset: 2, value: g8-5, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB24_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB24_1-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  # BB#2: # %b
 ; CHECK-NEXT:    jmp b # TAILCALL
-; CHECK-NEXT:  .LBB11_1: # %a
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB24_1: # %a
 ; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
 entry:
   %load1 = load i8, i8* @g8
-  %sub = sub nsw i8 %load1, 42
+  ; Subtract -0x80, which requires an 8-bit immediate but still gets lowered as
+  ; an add.
+  %sub = sub i8 %load1, -128
   store i8 %sub, i8* @g8
   %cond = icmp slt i8 %sub, 0
   br i1 %cond, label %a, label %b
@@ -322,15 +823,21 @@
 define void @sub64_reg_br(i64 %arg) nounwind {
 ; CHECK-LABEL: sub64_reg_br:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    subq %rdi, {{.*}}(%rip)
-; CHECK-NEXT:    js .LBB12_1
+; CHECK-NEXT:    subq %rdi, {{.*}}(%rip) # encoding: [0x48,0x29,0x3d,A,A,A,A]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g64-4, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB25_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB25_1-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  # BB#2: # %b
 ; CHECK-NEXT:    jmp b # TAILCALL
-; CHECK-NEXT:  .LBB12_1: # %a
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB25_1: # %a
 ; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
 entry:
   %load1 = load i64, i64* @g64
-  %sub = sub nsw i64 %load1, %arg
+  %sub = sub i64 %load1, %arg
   store i64 %sub, i64* @g64
   %cond = icmp slt i64 %sub, 0
   br i1 %cond, label %a, label %b
@@ -347,15 +854,21 @@
 define void @sub32_reg_br(i32 %arg) nounwind {
 ; CHECK-LABEL: sub32_reg_br:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    subl %edi, {{.*}}(%rip)
-; CHECK-NEXT:    js .LBB13_1
+; CHECK-NEXT:    subl %edi, {{.*}}(%rip) # encoding: [0x29,0x3d,A,A,A,A]
+; CHECK-NEXT:    # fixup A - offset: 2, value: g32-4, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB26_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB26_1-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  # BB#2: # %b
 ; CHECK-NEXT:    jmp b # TAILCALL
-; CHECK-NEXT:  .LBB13_1: # %a
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB26_1: # %a
 ; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
 entry:
   %load1 = load i32, i32* @g32
-  %sub = sub nsw i32 %load1, %arg
+  %sub = sub i32 %load1, %arg
   store i32 %sub, i32* @g32
   %cond = icmp slt i32 %sub, 0
   br i1 %cond, label %a, label %b
@@ -372,15 +885,21 @@
 define void @sub16_reg_br(i16 %arg) nounwind {
 ; CHECK-LABEL: sub16_reg_br:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    subw %di, {{.*}}(%rip)
-; CHECK-NEXT:    js .LBB14_1
+; CHECK-NEXT:    subw %di, {{.*}}(%rip) # encoding: [0x66,0x29,0x3d,A,A,A,A]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g16-4, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB27_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB27_1-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  # BB#2: # %b
 ; CHECK-NEXT:    jmp b # TAILCALL
-; CHECK-NEXT:  .LBB14_1: # %a
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB27_1: # %a
 ; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
 entry:
   %load1 = load i16, i16* @g16
-  %sub = sub nsw i16 %load1, %arg
+  %sub = sub i16 %load1, %arg
   store i16 %sub, i16* @g16
   %cond = icmp slt i16 %sub, 0
   br i1 %cond, label %a, label %b
@@ -397,15 +916,21 @@
 define void @sub8_reg_br(i8 %arg) nounwind {
 ; CHECK-LABEL: sub8_reg_br:
 ; CHECK:       # BB#0: # %entry
-; CHECK-NEXT:    subb %dil, {{.*}}(%rip)
-; CHECK-NEXT:    js .LBB15_1
+; CHECK-NEXT:    subb %dil, {{.*}}(%rip) # encoding: [0x40,0x28,0x3d,A,A,A,A]
+; CHECK-NEXT:    # fixup A - offset: 3, value: g8-4, kind: reloc_riprel_4byte
+; CHECK-NEXT:    js .LBB28_1 # encoding: [0x78,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: .LBB28_1-1, kind: FK_PCRel_1
 ; CHECK-NEXT:  # BB#2: # %b
 ; CHECK-NEXT:    jmp b # TAILCALL
-; CHECK-NEXT:  .LBB15_1: # %a
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: b-1, kind: FK_PCRel_1
+; CHECK-NEXT:  .LBB28_1: # %a
 ; CHECK-NEXT:    jmp a # TAILCALL
+; CHECK-NEXT:    # encoding: [0xeb,A]
+; CHECK-NEXT:    # fixup A - offset: 1, value: a-1, kind: FK_PCRel_1
 entry:
   %load1 = load i8, i8* @g8
-  %sub = sub nsw i8 %load1, %arg
+  %sub = sub i8 %load1, %arg
   store i8 %sub, i8* @g8
   %cond = icmp slt i8 %sub, 0
   br i1 %cond, label %a, label %b
Index: test/CodeGen/X86/peephole-na-phys-copy-folding.ll
===================================================================
--- test/CodeGen/X86/peephole-na-phys-copy-folding.ll
+++ test/CodeGen/X86/peephole-na-phys-copy-folding.ll
@@ -66,8 +66,7 @@
 ; CHECK32-LABEL: plus_forty_two:
 ; CHECK32:       # BB#0: # %entry
 ; CHECK32-NEXT:    movb M, %al
-; CHECK32-NEXT:    movl $42, %ecx
-; CHECK32-NEXT:    addl %ecx, L
+; CHECK32-NEXT:    addl $42, L
 ; CHECK32-NEXT:    jne .LBB1_2
 ; CHECK32-NEXT:  # BB#1: # %entry
 ; CHECK32-NEXT:    andb $8, %al
@@ -82,8 +81,7 @@
 ; CHECK64-LABEL: plus_forty_two:
 ; CHECK64:       # BB#0: # %entry
 ; CHECK64-NEXT:    movb {{.*}}(%rip), %al
-; CHECK64-NEXT:    movl $42, %ecx
-; CHECK64-NEXT:    addl %ecx, {{.*}}(%rip)
+; CHECK64-NEXT:    addl $42, {{.*}}(%rip)
 ; CHECK64-NEXT:    jne .LBB1_2
 ; CHECK64-NEXT:  # BB#1: # %entry
 ; CHECK64-NEXT:    andb $8, %al
@@ -164,8 +162,7 @@
 ; CHECK32-LABEL: minus_forty_two:
 ; CHECK32:       # BB#0: # %entry
 ; CHECK32-NEXT:    movb M, %al
-; CHECK32-NEXT:    movl $-42, %ecx
-; CHECK32-NEXT:    addl %ecx, L
+; CHECK32-NEXT:    addl $-42, L
 ; CHECK32-NEXT:    jne .LBB3_2
 ; CHECK32-NEXT:  # BB#1: # %entry
 ; CHECK32-NEXT:    andb $8, %al
@@ -180,8 +177,7 @@
 ; CHECK64-LABEL: minus_forty_two:
 ; CHECK64:       # BB#0: # %entry
 ; CHECK64-NEXT:    movb {{.*}}(%rip), %al
-; CHECK64-NEXT:    movl $-42, %ecx
-; CHECK64-NEXT:    addl %ecx, {{.*}}(%rip)
+; CHECK64-NEXT:    addl $-42, {{.*}}(%rip)
 ; CHECK64-NEXT:    jne .LBB3_2
 ; CHECK64-NEXT:  # BB#1: # %entry
 ; CHECK64-NEXT:    andb $8, %al
Index: test/CodeGen/X86/pr32659.ll
===================================================================
--- test/CodeGen/X86/pr32659.ll
+++ test/CodeGen/X86/pr32659.ll
@@ -50,9 +50,7 @@
 ; CHECK-NEXT:    sarl $31, %eax
 ; CHECK-NEXT:    andl %eax, e+4
 ; CHECK-NEXT:    decl g
-; CHECK-NEXT:    xorl %eax, %eax
-; CHECK-NEXT:    incl %eax
-; CHECK-NEXT:    addl %eax, f
+; CHECK-NEXT:    addl $1, f
 ; CHECK-NEXT:    adcl $0, f+4
 ; CHECK-NEXT:    addl $8, %esp
 ; CHECK-NEXT:    popl %ebx