Index: llvm/trunk/lib/Target/X86/X86ISelLowering.h
===================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.h
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.h
@@ -1478,6 +1478,9 @@
 
     /// Reassociate floating point divisions into multiply by reciprocal.
     unsigned combineRepeatedFPDivisors() const override;
+
+    SDValue BuildSDIVPow2(SDNode *N, const APInt &Divisor, SelectionDAG &DAG,
+                          SmallVectorImpl<SDNode *> &Created) const override;
   };
 
   namespace X86 {
Index: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
@@ -20080,6 +20080,61 @@
   return 2;
 }
 
+SDValue
+X86TargetLowering::BuildSDIVPow2(SDNode *N, const APInt &Divisor,
+                                 SelectionDAG &DAG,
+                                 SmallVectorImpl<SDNode *> &Created) const {
+  AttributeList Attr = DAG.getMachineFunction().getFunction().getAttributes();
+  if (isIntDivCheap(N->getValueType(0), Attr))
+    return SDValue(N,0); // Lower SDIV as SDIV
+
+  assert((Divisor.isPowerOf2() || (-Divisor).isPowerOf2()) &&
+         "Unexpected divisor!");
+
+  // Only perform this transform if CMOV is supported otherwise the select
+  // below will become a branch.
+  if (!Subtarget.hasCMov())
+    return SDValue();
+
+  // fold (sdiv X, pow2)
+  EVT VT = N->getValueType(0);
+  // FIXME: Support i8/i16.
+  if ((VT != MVT::i32 && !(Subtarget.is64Bit() && VT == MVT::i64)))
+    return SDValue();
+
+  unsigned Lg2 = Divisor.countTrailingZeros();
+
+  // If the divisor is 2 or -2, the default expansion is better.
+  if (Lg2 == 1)
+    return SDValue();
+
+  SDLoc DL(N);
+  SDValue N0 = N->getOperand(0);
+  SDValue Zero = DAG.getConstant(0, DL, VT);
+  SDValue Pow2MinusOne = DAG.getConstant((1ULL << Lg2) - 1, DL, VT);
+
+  // If N0 is negative, we need to add (Pow2 - 1) to it before shifting right.
+  SDValue Cmp = DAG.getSetCC(DL, MVT::i8, N0, Zero, ISD::SETLT);
+  SDValue Add = DAG.getNode(ISD::ADD, DL, VT, N0, Pow2MinusOne);
+  SDValue CMov = DAG.getNode(ISD::SELECT, DL, VT, Cmp, Add, N0);
+
+  Created.push_back(Cmp.getNode());
+  Created.push_back(Add.getNode());
+  Created.push_back(CMov.getNode());
+
+  // Divide by pow2.
+  SDValue SRA =
+      DAG.getNode(ISD::SRA, DL, VT, CMov, DAG.getConstant(Lg2, DL, MVT::i64));
+
+  // If we're dividing by a positive value, we're done.  Otherwise, we must
+  // negate the result.
+  if (Divisor.isNonNegative())
+    return SRA;
+
+  Created.push_back(SRA.getNode());
+  return DAG.getNode(ISD::SUB, DL, VT, Zero, SRA);
+}
+
 /// Result of 'and' is compared against zero. Change to a BT node if possible.
 /// Returns the BT node and the condition code needed to use it.
 static SDValue LowerAndToBT(SDValue And, ISD::CondCode CC,
Index: llvm/trunk/test/CodeGen/X86/combine-sdiv.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/combine-sdiv.ll
+++ llvm/trunk/test/CodeGen/X86/combine-sdiv.ll
@@ -3200,10 +3200,9 @@
 ; CHECK-LABEL: combine_i32_sdiv_pow2:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    # kill: def $edi killed $edi def $rdi
-; CHECK-NEXT:    movl %edi, %eax
-; CHECK-NEXT:    sarl $31, %eax
-; CHECK-NEXT:    shrl $28, %eax
-; CHECK-NEXT:    addl %edi, %eax
+; CHECK-NEXT:    leal 15(%rdi), %eax
+; CHECK-NEXT:    testl %edi, %edi
+; CHECK-NEXT:    cmovnsl %edi, %eax
 ; CHECK-NEXT:    sarl $4, %eax
 ; CHECK-NEXT:    retq
   %1 = sdiv i32 %x, 16
@@ -3214,10 +3213,9 @@
 ; CHECK-LABEL: combine_i32_sdiv_negpow2:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    # kill: def $edi killed $edi def $rdi
-; CHECK-NEXT:    movl %edi, %eax
-; CHECK-NEXT:    sarl $31, %eax
-; CHECK-NEXT:    shrl $24, %eax
-; CHECK-NEXT:    addl %edi, %eax
+; CHECK-NEXT:    leal 255(%rdi), %eax
+; CHECK-NEXT:    testl %edi, %edi
+; CHECK-NEXT:    cmovnsl %edi, %eax
 ; CHECK-NEXT:    sarl $8, %eax
 ; CHECK-NEXT:    negl %eax
 ; CHECK-NEXT:    retq
@@ -3228,10 +3226,9 @@
 define i64 @combine_i64_sdiv_pow2(i64 %x) {
 ; CHECK-LABEL: combine_i64_sdiv_pow2:
 ; CHECK:       # %bb.0:
-; CHECK-NEXT:    movq %rdi, %rax
-; CHECK-NEXT:    sarq $63, %rax
-; CHECK-NEXT:    shrq $60, %rax
-; CHECK-NEXT:    addq %rdi, %rax
+; CHECK-NEXT:    leaq 15(%rdi), %rax
+; CHECK-NEXT:    testq %rdi, %rdi
+; CHECK-NEXT:    cmovnsq %rdi, %rax
 ; CHECK-NEXT:    sarq $4, %rax
 ; CHECK-NEXT:    retq
   %1 = sdiv i64 %x, 16
@@ -3241,10 +3238,9 @@
 define i64 @combine_i64_sdiv_negpow2(i64 %x) {
 ; CHECK-LABEL: combine_i64_sdiv_negpow2:
 ; CHECK:       # %bb.0:
-; CHECK-NEXT:    movq %rdi, %rax
-; CHECK-NEXT:    sarq $63, %rax
-; CHECK-NEXT:    shrq $56, %rax
-; CHECK-NEXT:    addq %rdi, %rax
+; CHECK-NEXT:    leaq 255(%rdi), %rax
+; CHECK-NEXT:    testq %rdi, %rdi
+; CHECK-NEXT:    cmovnsq %rdi, %rax
 ; CHECK-NEXT:    sarq $8, %rax
 ; CHECK-NEXT:    negq %rax
 ; CHECK-NEXT:    retq
Index: llvm/trunk/test/CodeGen/X86/combine-srem.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/combine-srem.ll
+++ llvm/trunk/test/CodeGen/X86/combine-srem.ll
@@ -56,10 +56,9 @@
 ; CHECK-LABEL: combine_srem_by_minsigned:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    # kill: def $edi killed $edi def $rdi
-; CHECK-NEXT:    movl %edi, %eax
-; CHECK-NEXT:    sarl $31, %eax
-; CHECK-NEXT:    shrl %eax
-; CHECK-NEXT:    addl %edi, %eax
+; CHECK-NEXT:    leal 2147483647(%rdi), %eax
+; CHECK-NEXT:    testl %edi, %edi
+; CHECK-NEXT:    cmovnsl %edi, %eax
 ; CHECK-NEXT:    andl $-2147483648, %eax # imm = 0x80000000
 ; CHECK-NEXT:    addl %edi, %eax
 ; CHECK-NEXT:    retq
@@ -513,12 +512,12 @@
 ; CHECK-LABEL: combine_srem_pow2:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    movl %edi, %eax
-; CHECK-NEXT:    movl %edi, %ecx
-; CHECK-NEXT:    sarl $31, %ecx
-; CHECK-NEXT:    shrl $28, %ecx
-; CHECK-NEXT:    addl %edi, %ecx
+; CHECK-NEXT:    leal 15(%rax), %ecx
+; CHECK-NEXT:    testl %edi, %edi
+; CHECK-NEXT:    cmovnsl %edi, %ecx
 ; CHECK-NEXT:    andl $-16, %ecx
 ; CHECK-NEXT:    subl %ecx, %eax
+; CHECK-NEXT:    # kill: def $eax killed $eax killed $rax
 ; CHECK-NEXT:    retq
   %1 = srem i32 %x, 16
   ret i32 %1
@@ -528,12 +527,12 @@
 ; CHECK-LABEL: combine_srem_negpow2:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    movl %edi, %eax
-; CHECK-NEXT:    movl %edi, %ecx
-; CHECK-NEXT:    sarl $31, %ecx
-; CHECK-NEXT:    shrl $24, %ecx
-; CHECK-NEXT:    addl %edi, %ecx
+; CHECK-NEXT:    leal 255(%rax), %ecx
+; CHECK-NEXT:    testl %edi, %edi
+; CHECK-NEXT:    cmovnsl %edi, %ecx
 ; CHECK-NEXT:    andl $-256, %ecx
 ; CHECK-NEXT:    subl %ecx, %eax
+; CHECK-NEXT:    # kill: def $eax killed $eax killed $rax
 ; CHECK-NEXT:    retq
   %1 = srem i32 %x, -256
   ret i32 %1
@@ -543,10 +542,9 @@
 ; CHECK-LABEL: combine_i64_srem_pow2:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    movq %rdi, %rax
-; CHECK-NEXT:    movq %rdi, %rcx
-; CHECK-NEXT:    sarq $63, %rcx
-; CHECK-NEXT:    shrq $60, %rcx
-; CHECK-NEXT:    addq %rdi, %rcx
+; CHECK-NEXT:    leaq 15(%rdi), %rcx
+; CHECK-NEXT:    testq %rdi, %rdi
+; CHECK-NEXT:    cmovnsq %rdi, %rcx
 ; CHECK-NEXT:    andq $-16, %rcx
 ; CHECK-NEXT:    subq %rcx, %rax
 ; CHECK-NEXT:    retq
@@ -558,10 +556,9 @@
 ; CHECK-LABEL: combine_i64_srem_negpow2:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    movq %rdi, %rax
-; CHECK-NEXT:    movq %rdi, %rcx
-; CHECK-NEXT:    sarq $63, %rcx
-; CHECK-NEXT:    shrq $56, %rcx
-; CHECK-NEXT:    addq %rdi, %rcx
+; CHECK-NEXT:    leaq 255(%rdi), %rcx
+; CHECK-NEXT:    testq %rdi, %rdi
+; CHECK-NEXT:    cmovnsq %rdi, %rcx
 ; CHECK-NEXT:    andq $-256, %rcx
 ; CHECK-NEXT:    subq %rcx, %rax
 ; CHECK-NEXT:    retq
Index: llvm/trunk/test/CodeGen/X86/rem.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/rem.ll
+++ llvm/trunk/test/CodeGen/X86/rem.ll
@@ -27,10 +27,9 @@
 ; CHECK-LABEL: test2:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    movl {{[0-9]+}}(%esp), %eax
-; CHECK-NEXT:    movl %eax, %ecx
-; CHECK-NEXT:    sarl $31, %ecx
-; CHECK-NEXT:    shrl $24, %ecx
-; CHECK-NEXT:    addl %eax, %ecx
+; CHECK-NEXT:    leal 255(%eax), %ecx
+; CHECK-NEXT:    testl %eax, %eax
+; CHECK-NEXT:    cmovnsl %eax, %ecx
 ; CHECK-NEXT:    andl $-256, %ecx
 ; CHECK-NEXT:    subl %ecx, %eax
 ; CHECK-NEXT:    retl
Index: llvm/trunk/test/CodeGen/X86/srem-seteq.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/srem-seteq.ll
+++ llvm/trunk/test/CodeGen/X86/srem-seteq.ll
@@ -318,10 +318,9 @@
 ; X86-LABEL: test_srem_pow2:
 ; X86:       # %bb.0:
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %ecx
-; X86-NEXT:    movl %ecx, %edx
-; X86-NEXT:    sarl $31, %edx
-; X86-NEXT:    shrl $28, %edx
-; X86-NEXT:    addl %ecx, %edx
+; X86-NEXT:    leal 15(%ecx), %edx
+; X86-NEXT:    testl %ecx, %ecx
+; X86-NEXT:    cmovnsl %ecx, %edx
 ; X86-NEXT:    andl $-16, %edx
 ; X86-NEXT:    xorl %eax, %eax
 ; X86-NEXT:    cmpl %edx, %ecx
@@ -330,10 +329,10 @@
 ;
 ; X64-LABEL: test_srem_pow2:
 ; X64:       # %bb.0:
-; X64-NEXT:    movl %edi, %ecx
-; X64-NEXT:    sarl $31, %ecx
-; X64-NEXT:    shrl $28, %ecx
-; X64-NEXT:    addl %edi, %ecx
+; X64-NEXT:    # kill: def $edi killed $edi def $rdi
+; X64-NEXT:    leal 15(%rdi), %ecx
+; X64-NEXT:    testl %edi, %edi
+; X64-NEXT:    cmovnsl %edi, %ecx
 ; X64-NEXT:    andl $-16, %ecx
 ; X64-NEXT:    xorl %eax, %eax
 ; X64-NEXT:    cmpl %ecx, %edi
@@ -350,10 +349,9 @@
 ; X86-LABEL: test_srem_int_min:
 ; X86:       # %bb.0:
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %ecx
-; X86-NEXT:    movl %ecx, %edx
-; X86-NEXT:    sarl $31, %edx
-; X86-NEXT:    shrl %edx
-; X86-NEXT:    addl %ecx, %edx
+; X86-NEXT:    leal 2147483647(%ecx), %edx
+; X86-NEXT:    testl %ecx, %ecx
+; X86-NEXT:    cmovnsl %ecx, %edx
 ; X86-NEXT:    andl $-2147483648, %edx # imm = 0x80000000
 ; X86-NEXT:    xorl %eax, %eax
 ; X86-NEXT:    addl %ecx, %edx
@@ -362,10 +360,10 @@
 ;
 ; X64-LABEL: test_srem_int_min:
 ; X64:       # %bb.0:
-; X64-NEXT:    movl %edi, %ecx
-; X64-NEXT:    sarl $31, %ecx
-; X64-NEXT:    shrl %ecx
-; X64-NEXT:    addl %edi, %ecx
+; X64-NEXT:    # kill: def $edi killed $edi def $rdi
+; X64-NEXT:    leal 2147483647(%rdi), %ecx
+; X64-NEXT:    testl %edi, %edi
+; X64-NEXT:    cmovnsl %edi, %ecx
 ; X64-NEXT:    andl $-2147483648, %ecx # imm = 0x80000000
 ; X64-NEXT:    xorl %eax, %eax
 ; X64-NEXT:    addl %edi, %ecx