diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index 23cd496adeb..0d97669b225 100644
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -2002,6 +2002,46 @@ let Predicates = [HasLZCNT], Defs = [EFLAGS] in {
                       (implicit EFLAGS)]>, XS;
 }
 
+let Predicates = [HasLZCNT] in {
+  def : Pat<(X86cmov (ctlz GR16:$src), (i16 16), (X86_COND_E),
+              (X86cmp GR16:$src, (i16 0))), 
+            (LZCNT16rr GR16:$src)>;
+  def : Pat<(X86cmov (ctlz GR32:$src), (i32 32), (X86_COND_E),
+              (X86cmp GR32:$src, (i32 0))),
+            (LZCNT32rr GR32:$src)>;
+  def : Pat<(X86cmov (ctlz GR64:$src), (i64 64), (X86_COND_E),
+              (X86cmp GR64:$src, (i64 0))),
+            (LZCNT64rr GR64:$src)>;
+  def : Pat<(X86cmov (i16 16), (ctlz GR16:$src), (X86_COND_E),
+              (X86cmp GR16:$src, (i16 0))),
+            (LZCNT16rr GR16:$src)>;
+  def : Pat<(X86cmov (i32 32), (ctlz GR32:$src), (X86_COND_E),
+              (X86cmp GR32:$src, (i32 0))),
+            (LZCNT32rr GR32:$src)>;
+  def : Pat<(X86cmov (i64 64), (ctlz GR64:$src), (X86_COND_E),
+              (X86cmp GR64:$src, (i64 0))),
+            (LZCNT64rr GR64:$src)>;
+
+  def : Pat<(X86cmov (ctlz (loadi16 addr:$src)), (i16 16), (X86_COND_E),
+              (X86cmp (loadi16 addr:$src), (i16 0))), 
+            (LZCNT16rm addr:$src)>;
+  def : Pat<(X86cmov (ctlz (loadi32 addr:$src)), (i32 32), (X86_COND_E),
+              (X86cmp (loadi32 addr:$src), (i32 0))), 
+            (LZCNT32rm addr:$src)>;
+  def : Pat<(X86cmov (ctlz (loadi64 addr:$src)), (i64 64), (X86_COND_E),
+              (X86cmp (loadi64 addr:$src), (i64 0))), 
+            (LZCNT64rm addr:$src)>;
+  def : Pat<(X86cmov (i16 16), (ctlz (loadi16 addr:$src)), (X86_COND_E),
+              (X86cmp (loadi16 addr:$src), (i16 0))), 
+            (LZCNT16rm addr:$src)>;
+  def : Pat<(X86cmov (i32 32), (ctlz (loadi32 addr:$src)), (X86_COND_E),
+              (X86cmp (loadi32 addr:$src), (i32 0))), 
+            (LZCNT32rm addr:$src)>;
+  def : Pat<(X86cmov (i64 64), (ctlz (loadi64 addr:$src)), (X86_COND_E),
+              (X86cmp (loadi64 addr:$src), (i64 0))), 
+            (LZCNT64rm addr:$src)>;
+}
+
 //===----------------------------------------------------------------------===//
 // BMI Instructions
 //
@@ -2078,6 +2118,47 @@ let Predicates = [HasBMI] in {
             (BLSI64rr GR64:$src)>;
 }
 
+let Predicates = [HasBMI] in {
+  def : Pat<(X86cmov (cttz GR16:$src), (i16 16), (X86_COND_E),
+              (X86cmp GR16:$src, (i16 0))),
+            (TZCNT16rr GR16:$src)>;
+  def : Pat<(X86cmov (cttz GR32:$src), (i32 32), (X86_COND_E),
+              (X86cmp GR32:$src, (i32 0))),
+            (TZCNT32rr GR32:$src)>;
+  def : Pat<(X86cmov (cttz GR64:$src), (i64 64), (X86_COND_E),
+              (X86cmp GR64:$src, (i64 0))),
+            (TZCNT64rr GR64:$src)>;
+  def : Pat<(X86cmov (i16 16), (cttz GR16:$src), (X86_COND_E),
+              (X86cmp GR16:$src, (i16 0))),
+            (TZCNT16rr GR16:$src)>;
+  def : Pat<(X86cmov (i32 32), (cttz GR32:$src), (X86_COND_E),
+              (X86cmp GR32:$src, (i32 0))),
+            (TZCNT32rr GR32:$src)>;
+  def : Pat<(X86cmov (i64 64), (cttz GR64:$src), (X86_COND_E),
+              (X86cmp GR64:$src, (i64 0))),
+            (TZCNT64rr GR64:$src)>;
+
+  def : Pat<(X86cmov (cttz (loadi16 addr:$src)), (i16 16), (X86_COND_E),
+              (X86cmp (loadi16 addr:$src), (i16 0))), 
+            (TZCNT16rm addr:$src)>;
+  def : Pat<(X86cmov (cttz (loadi32 addr:$src)), (i32 32), (X86_COND_E),
+              (X86cmp (loadi32 addr:$src), (i32 0))), 
+            (TZCNT32rm addr:$src)>;
+  def : Pat<(X86cmov (cttz (loadi64 addr:$src)), (i64 64), (X86_COND_E),
+              (X86cmp (loadi64 addr:$src), (i64 0))), 
+            (TZCNT64rm addr:$src)>;
+  def : Pat<(X86cmov (i16 16), (cttz (loadi16 addr:$src)), (X86_COND_E),
+              (X86cmp (loadi16 addr:$src), (i16 0))), 
+            (TZCNT16rm addr:$src)>;
+  def : Pat<(X86cmov (i32 32), (cttz (loadi32 addr:$src)), (X86_COND_E),
+              (X86cmp (loadi32 addr:$src), (i32 0))), 
+            (TZCNT32rm addr:$src)>;
+  def : Pat<(X86cmov (i64 64), (cttz (loadi64 addr:$src)), (X86_COND_E),
+              (X86cmp (loadi64 addr:$src), (i64 0))), 
+            (TZCNT64rm addr:$src)>;
+}
+
+
 multiclass bmi_bextr_bzhi<bits<8> opc, string mnemonic, RegisterClass RC,
                           X86MemOperand x86memop, Intrinsic Int,
                           PatFrag ld_frag> {
diff --git a/test/CodeGen/X86/lzcnt-tzcnt.ll b/test/CodeGen/X86/lzcnt-tzcnt.ll
new file mode 100644
index 00000000000..07e4b9d8ce6
--- /dev/null
+++ b/test/CodeGen/X86/lzcnt-tzcnt.ll
@@ -0,0 +1,447 @@
+; RUN: llc < %s -mtriple=x86_64-pc-linux -mattr=+bmi,+lzcnt | FileCheck %s
+
+; LZCNT and TZCNT will always produce the operand size when the input operand
+; is zero. This test is to verify that we efficiently select LZCNT/TZCNT
+; based on the fact that the 'icmp+select' sequence is always redundant
+; in every function defined below.
+
+
+define i16 @test1_ctlz(i16 %v) {
+  %cnt = tail call i16 @llvm.ctlz.i16(i16 %v, i1 true)
+  %tobool = icmp eq i16 %v, 0
+  %cond = select i1 %tobool, i16 16, i16 %cnt
+  ret i16 %cond
+}
+; CHECK-LABEL: test1_ctlz
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i32 @test2_ctlz(i32 %v) {
+  %cnt = tail call i32 @llvm.ctlz.i32(i32 %v, i1 true)
+  %tobool = icmp eq i32 %v, 0
+  %cond = select i1 %tobool, i32 32, i32 %cnt
+  ret i32 %cond
+}
+; CHECK-LABEL: test2_ctlz
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i64 @test3_ctlz(i64 %v) {
+  %cnt = tail call i64 @llvm.ctlz.i64(i64 %v, i1 true)
+  %tobool = icmp eq i64 %v, 0
+  %cond = select i1 %tobool, i64 64, i64 %cnt
+  ret i64 %cond
+}
+; CHECK-LABEL: test3_ctlz
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i16 @test4_ctlz(i16 %v) {
+  %cnt = tail call i16 @llvm.ctlz.i16(i16 %v, i1 true)
+  %tobool = icmp eq i16 0, %v
+  %cond = select i1 %tobool, i16 16, i16 %cnt
+  ret i16 %cond
+}
+; CHECK-LABEL: test4_ctlz
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i32 @test5_ctlz(i32 %v) {
+  %cnt = tail call i32 @llvm.ctlz.i32(i32 %v, i1 true)
+  %tobool = icmp eq i32 0, %v
+  %cond = select i1 %tobool, i32 32, i32 %cnt
+  ret i32 %cond
+}
+; CHECK-LABEL: test5_ctlz
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i64 @test6_ctlz(i64 %v) {
+  %cnt = tail call i64 @llvm.ctlz.i64(i64 %v, i1 true)
+  %tobool = icmp eq i64 0, %v
+  %cond = select i1 %tobool, i64 64, i64 %cnt
+  ret i64 %cond
+}
+; CHECK-LABEL: test6_ctlz
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i16 @test7_ctlz(i16 %v) {
+  %cnt = tail call i16 @llvm.ctlz.i16(i16 %v, i1 true)
+  %tobool = icmp eq i16 0, %v
+  %cond = select i1 %tobool, i16 %cnt, i16 16
+  ret i16 %cond
+}
+; CHECK-LABEL: test7_ctlz
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i32 @test8_ctlz(i32 %v) {
+  %cnt = tail call i32 @llvm.ctlz.i32(i32 %v, i1 true)
+  %tobool = icmp eq i32 0, %v
+  %cond = select i1 %tobool, i32 %cnt, i32 32
+  ret i32 %cond
+}
+; CHECK-LABEL: test8_ctlz
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i64 @test9_ctlz(i64 %v) {
+  %cnt = tail call i64 @llvm.ctlz.i64(i64 %v, i1 true)
+  %tobool = icmp eq i64 0, %v
+  %cond = select i1 %tobool, i64 %cnt, i64 64
+  ret i64 %cond
+}
+; CHECK-LABEL: test9_ctlz
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i16 @test10_ctlz(i16* %ptr) {
+  %v = load i16* %ptr
+  %cnt = tail call i16 @llvm.ctlz.i16(i16 %v, i1 true)
+  %tobool = icmp eq i16 %v, 0
+  %cond = select i1 %tobool, i16 16, i16 %cnt
+  ret i16 %cond
+}
+; CHECK-LABEL: test10_ctlz
+; CHECK-NOT: movw
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i32 @test11_ctlz(i32* %ptr) {
+  %v = load i32* %ptr
+  %cnt = tail call i32 @llvm.ctlz.i32(i32 %v, i1 true)
+  %tobool = icmp eq i32 %v, 0
+  %cond = select i1 %tobool, i32 32, i32 %cnt
+  ret i32 %cond
+}
+; CHECK-LABEL: test11_ctlz
+; CHECK-NOT: movd
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i64 @test12_ctlz(i64* %ptr) {
+  %v = load i64* %ptr
+  %cnt = tail call i64 @llvm.ctlz.i64(i64 %v, i1 true)
+  %tobool = icmp eq i64 %v, 0
+  %cond = select i1 %tobool, i64 64, i64 %cnt
+  ret i64 %cond
+}
+; CHECK-LABEL: test12_ctlz
+; CHECK-NOT: movq
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i16 @test13_ctlz(i16* %ptr) {
+  %v = load i16* %ptr
+  %cnt = tail call i16 @llvm.ctlz.i16(i16 %v, i1 true)
+  %tobool = icmp eq i16 0, %v
+  %cond = select i1 %tobool, i16 16, i16 %cnt
+  ret i16 %cond
+}
+; CHECK-LABEL: test13_ctlz
+; CHECK-NOT: movw
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i32 @test14_ctlz(i32* %ptr) {
+  %v = load i32* %ptr
+  %cnt = tail call i32 @llvm.ctlz.i32(i32 %v, i1 true)
+  %tobool = icmp eq i32 0, %v
+  %cond = select i1 %tobool, i32 32, i32 %cnt
+  ret i32 %cond
+}
+; CHECK-LABEL: test14_ctlz
+; CHECK-NOT: movd
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i64 @test15_ctlz(i64* %ptr) {
+  %v = load i64* %ptr
+  %cnt = tail call i64 @llvm.ctlz.i64(i64 %v, i1 true)
+  %tobool = icmp eq i64 0, %v
+  %cond = select i1 %tobool, i64 64, i64 %cnt
+  ret i64 %cond
+}
+; CHECK-LABEL: test15_ctlz
+; CHECK-NOT: movq
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i16 @test16_ctlz(i16* %ptr) {
+  %v = load i16* %ptr
+  %cnt = tail call i16 @llvm.ctlz.i16(i16 %v, i1 true)
+  %tobool = icmp eq i16 0, %v
+  %cond = select i1 %tobool, i16 %cnt, i16 16
+  ret i16 %cond
+}
+; CHECK-LABEL: test16_ctlz
+; CHECK-NOT: movw
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i32 @test17_ctlz(i32* %ptr) {
+  %v = load i32* %ptr
+  %cnt = tail call i32 @llvm.ctlz.i32(i32 %v, i1 true)
+  %tobool = icmp eq i32 0, %v
+  %cond = select i1 %tobool, i32 %cnt, i32 32
+  ret i32 %cond
+}
+; CHECK-LABEL: test17_ctlz
+; CHECK-NOT: movd
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i64 @test18_ctlz(i64* %ptr) {
+  %v = load i64* %ptr
+  %cnt = tail call i64 @llvm.ctlz.i64(i64 %v, i1 true)
+  %tobool = icmp eq i64 0, %v
+  %cond = select i1 %tobool, i64 %cnt, i64 64
+  ret i64 %cond
+}
+; CHECK-LABEL: test18_ctlz
+; CHECK-NOT: movq
+; CHECK: lzcnt
+; CHECK-NEXT: ret
+
+
+define i16 @test1_cttz(i16 %v) {
+  %cnt = tail call i16 @llvm.cttz.i16(i16 %v, i1 true)
+  %tobool = icmp eq i16 %v, 0
+  %cond = select i1 %tobool, i16 16, i16 %cnt
+  ret i16 %cond
+}
+; CHECK-LABEL: test1_cttz
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i32 @test2_cttz(i32 %v) {
+  %cnt = tail call i32 @llvm.cttz.i32(i32 %v, i1 true)
+  %tobool = icmp eq i32 %v, 0
+  %cond = select i1 %tobool, i32 32, i32 %cnt
+  ret i32 %cond
+}
+; CHECK-LABEL: test2_cttz
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i64 @test3_cttz(i64 %v) {
+  %cnt = tail call i64 @llvm.cttz.i64(i64 %v, i1 true)
+  %tobool = icmp eq i64 %v, 0
+  %cond = select i1 %tobool, i64 64, i64 %cnt
+  ret i64 %cond
+}
+; CHECK-LABEL: test3_cttz
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i16 @test4_cttz(i16 %v) {
+  %cnt = tail call i16 @llvm.cttz.i16(i16 %v, i1 true)
+  %tobool = icmp eq i16 0, %v
+  %cond = select i1 %tobool, i16 16, i16 %cnt
+  ret i16 %cond
+}
+; CHECK-LABEL: test4_cttz
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i32 @test5_cttz(i32 %v) {
+  %cnt = tail call i32 @llvm.cttz.i32(i32 %v, i1 true)
+  %tobool = icmp eq i32 0, %v
+  %cond = select i1 %tobool, i32 32, i32 %cnt
+  ret i32 %cond
+}
+; CHECK-LABEL: test5_cttz
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i64 @test6_cttz(i64 %v) {
+  %cnt = tail call i64 @llvm.cttz.i64(i64 %v, i1 true)
+  %tobool = icmp eq i64 0, %v
+  %cond = select i1 %tobool, i64 64, i64 %cnt
+  ret i64 %cond
+}
+; CHECK-LABEL: test6_cttz
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i16 @test7_cttz(i16 %v) {
+  %cnt = tail call i16 @llvm.cttz.i16(i16 %v, i1 true)
+  %tobool = icmp eq i16 0, %v
+  %cond = select i1 %tobool, i16 %cnt, i16 16
+  ret i16 %cond
+}
+; CHECK-LABEL: test7_cttz
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i32 @test8_cttz(i32 %v) {
+  %cnt = tail call i32 @llvm.cttz.i32(i32 %v, i1 true)
+  %tobool = icmp eq i32 0, %v
+  %cond = select i1 %tobool, i32 %cnt, i32 32
+  ret i32 %cond
+}
+; CHECK-LABEL: test8_cttz
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i64 @test9_cttz(i64 %v) {
+  %cnt = tail call i64 @llvm.cttz.i64(i64 %v, i1 true)
+  %tobool = icmp eq i64 0, %v
+  %cond = select i1 %tobool, i64 %cnt, i64 64
+  ret i64 %cond
+}
+; CHECK-LABEL: test9_cttz
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i16 @test10_cttz(i16* %ptr) {
+  %v = load i16* %ptr
+  %cnt = tail call i16 @llvm.cttz.i16(i16 %v, i1 true)
+  %tobool = icmp eq i16 %v, 0
+  %cond = select i1 %tobool, i16 16, i16 %cnt
+  ret i16 %cond
+}
+; CHECK-LABEL: test10_cttz
+; CHECK-NOT: movw
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i32 @test11_cttz(i32* %ptr) {
+  %v = load i32* %ptr
+  %cnt = tail call i32 @llvm.cttz.i32(i32 %v, i1 true)
+  %tobool = icmp eq i32 %v, 0
+  %cond = select i1 %tobool, i32 32, i32 %cnt
+  ret i32 %cond
+}
+; CHECK-LABEL: test11_cttz
+; CHECK-NOT: movd
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i64 @test12_cttz(i64* %ptr) {
+  %v = load i64* %ptr
+  %cnt = tail call i64 @llvm.cttz.i64(i64 %v, i1 true)
+  %tobool = icmp eq i64 %v, 0
+  %cond = select i1 %tobool, i64 64, i64 %cnt
+  ret i64 %cond
+}
+; CHECK-LABEL: test12_cttz
+; CHECK-NOT: movq
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i16 @test13_cttz(i16* %ptr) {
+  %v = load i16* %ptr
+  %cnt = tail call i16 @llvm.cttz.i16(i16 %v, i1 true)
+  %tobool = icmp eq i16 0, %v
+  %cond = select i1 %tobool, i16 16, i16 %cnt
+  ret i16 %cond
+}
+; CHECK-LABEL: test13_cttz
+; CHECK-NOT: movw
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i32 @test14_cttz(i32* %ptr) {
+  %v = load i32* %ptr
+  %cnt = tail call i32 @llvm.cttz.i32(i32 %v, i1 true)
+  %tobool = icmp eq i32 0, %v
+  %cond = select i1 %tobool, i32 32, i32 %cnt
+  ret i32 %cond
+}
+; CHECK-LABEL: test14_cttz
+; CHECK-NOT: movd
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i64 @test15_cttz(i64* %ptr) {
+  %v = load i64* %ptr
+  %cnt = tail call i64 @llvm.cttz.i64(i64 %v, i1 true)
+  %tobool = icmp eq i64 0, %v
+  %cond = select i1 %tobool, i64 64, i64 %cnt
+  ret i64 %cond
+}
+; CHECK-LABEL: test15_cttz
+; CHECK-NOT: movq
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i16 @test16_cttz(i16* %ptr) {
+  %v = load i16* %ptr
+  %cnt = tail call i16 @llvm.cttz.i16(i16 %v, i1 true)
+  %tobool = icmp eq i16 0, %v
+  %cond = select i1 %tobool, i16 %cnt, i16 16
+  ret i16 %cond
+}
+; CHECK-LABEL: test16_cttz
+; CHECK-NOT: movw
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i32 @test17_cttz(i32* %ptr) {
+  %v = load i32* %ptr
+  %cnt = tail call i32 @llvm.cttz.i32(i32 %v, i1 true)
+  %tobool = icmp eq i32 0, %v
+  %cond = select i1 %tobool, i32 %cnt, i32 32
+  ret i32 %cond
+}
+; CHECK-LABEL: test17_cttz
+; CHECK-NOT: movd
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+define i64 @test18_cttz(i64* %ptr) {
+  %v = load i64* %ptr
+  %cnt = tail call i64 @llvm.cttz.i64(i64 %v, i1 true)
+  %tobool = icmp eq i64 0, %v
+  %cond = select i1 %tobool, i64 %cnt, i64 64
+  ret i64 %cond
+}
+; CHECK-LABEL: test18_cttz
+; CHECK-NOT: movq
+; CHECK: tzcnt
+; CHECK-NEXT: ret
+
+
+declare i64 @llvm.cttz.i64(i64, i1)
+declare i32 @llvm.cttz.i32(i32, i1)
+declare i16 @llvm.cttz.i16(i16, i1)
+declare i64 @llvm.ctlz.i64(i64, i1)
+declare i32 @llvm.ctlz.i32(i32, i1)
+declare i16 @llvm.ctlz.i16(i16, i1)
+