Index: lib/Target/AMDGPU/AMDGPUISelLowering.cpp
===================================================================
--- lib/Target/AMDGPU/AMDGPUISelLowering.cpp
+++ lib/Target/AMDGPU/AMDGPUISelLowering.cpp
@@ -2595,27 +2595,49 @@
 
 SDValue AMDGPUTargetLowering::performShlCombine(SDNode *N,
                                                 DAGCombinerInfo &DCI) const {
-  if (N->getValueType(0) != MVT::i64)
+  EVT VT = N->getValueType(0);
+  if (VT != MVT::i64)
     return SDValue();
 
-  // i64 (shl x, C) -> (build_pair 0, (shl x, C -32))
-
-  // On some subtargets, 64-bit shift is a quarter rate instruction. In the
-  // common case, splitting this into a move and a 32-bit shift is faster and
-  // the same code size.
-  const ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(N->getOperand(1));
+  ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(N->getOperand(1));
   if (!RHS)
     return SDValue();
 
-  unsigned RHSVal = RHS->getZExtValue();
-  if (RHSVal < 32)
-    return SDValue();
-
   SDValue LHS = N->getOperand(0);
+  unsigned RHSVal = RHS->getZExtValue();
+  if (!RHSVal)
+    return LHS;
 
   SDLoc SL(N);
   SelectionDAG &DAG = DCI.DAG;
 
+  switch (LHS->getOpcode()) {
+  default:
+    break;
+  case ISD::ZERO_EXTEND:
+  case ISD::SIGN_EXTEND:
+  case ISD::ANY_EXTEND: {
+    // shl (ext x) => zext (shl x), if shift does not overflow int
+    KnownBits Known;
+    SDValue X = LHS->getOperand(0);
+    DAG.computeKnownBits(X, Known);
+    unsigned LZ = Known.countMinLeadingZeros();
+    if (LZ < RHSVal)
+      break;
+    EVT XVT = X.getValueType();
+    SDValue Shl = DAG.getNode(ISD::SHL, SL, XVT, X, SDValue(RHS, 0));
+    return DAG.getZExtOrTrunc(Shl, SL, VT);
+  }
+  }
+
+  // i64 (shl x, C) -> (build_pair 0, (shl x, C -32))
+
+  // On some subtargets, 64-bit shift is a quarter rate instruction. In the
+  // common case, splitting this into a move and a 32-bit shift is faster and
+  // the same code size.
+  if (RHSVal < 32)
+    return SDValue();
+
   SDValue ShiftAmt = DAG.getConstant(RHSVal - 32, SL, MVT::i32);
 
   SDValue Lo = DAG.getNode(ISD::TRUNCATE, SL, MVT::i32, LHS);
Index: test/CodeGen/AMDGPU/add.i16.ll
===================================================================
--- test/CodeGen/AMDGPU/add.i16.ll
+++ test/CodeGen/AMDGPU/add.i16.ll
@@ -84,11 +84,10 @@
 
 ; FIXME: Need to handle non-uniform case for function below (load without gep).
 ; GCN-LABEL: {{^}}v_test_add_i16_zext_to_i64:
-; VI-DAG: v_mov_b32_e32 v[[VZERO:[0-9]+]], 0
 ; VI: flat_load_ushort [[A:v[0-9]+]]
 ; VI: flat_load_ushort [[B:v[0-9]+]]
 ; VI-DAG: v_add_u16_e32 v[[ADD:[0-9]+]], [[B]], [[A]]
-; VI: buffer_store_dwordx2 v{{\[}}[[ADD]]:[[VZERO]]{{\]}}, off, {{s\[[0-9]+:[0-9]+\]}}, 0{{$}}
+; VI: buffer_store_dwordx2 v{{\[}}[[ADD]]:{{[0-9]+\]}}, off, {{s\[[0-9]+:[0-9]+\]}}, 0{{$}}
 define amdgpu_kernel void @v_test_add_i16_zext_to_i64(i64 addrspace(1)* %out, i16 addrspace(1)* %in0, i16 addrspace(1)* %in1) #1 {
   %tid = call i32 @llvm.amdgcn.workitem.id.x()
   %gep.out = getelementptr inbounds i64, i64 addrspace(1)* %out, i32 %tid
Index: test/CodeGen/AMDGPU/add.v2i16.ll
===================================================================
--- test/CodeGen/AMDGPU/add.v2i16.ll
+++ test/CodeGen/AMDGPU/add.v2i16.ll
@@ -202,10 +202,10 @@
 ; VI: flat_load_ushort v[[B_LO:[0-9]+]]
 ; VI: flat_load_ushort v[[B_HI:[0-9]+]]
 
-; VI: v_mov_b32_e32 v{{[0-9]+}}, 0{{$}}
-; VI: v_mov_b32_e32 v{{[0-9]+}}, 0{{$}}
-; VI: v_add_u16_e32
-; VI: v_add_u16_e32
+; VI-DAG: v_mov_b32_e32 v{{[0-9]+}}, 0{{$}}
+; VI-DAG: v_mov_b32_e32 v{{[0-9]+}}, 0{{$}}
+; VI-DAG: v_add_u16_e32
+; VI-DAG: v_add_u16_e32
 
 ; VI: buffer_store_dwordx4
 define amdgpu_kernel void @v_test_add_v2i16_zext_to_v2i64(<2 x i64> addrspace(1)* %out, <2 x i16> addrspace(1)* %in0, <2 x i16> addrspace(1)* %in1) #1 {
Index: test/CodeGen/AMDGPU/bfe-patterns.ll
===================================================================
--- test/CodeGen/AMDGPU/bfe-patterns.ll
+++ test/CodeGen/AMDGPU/bfe-patterns.ll
@@ -50,7 +50,7 @@
 ; GCN-LABEL: {{^}}s_ubfe_sub_i32:
 ; GCN: s_load_dword [[SRC:s[0-9]+]]
 ; GCN: s_load_dword [[WIDTH:s[0-9]+]]
-; GCN: v_mov_b32_e32 [[VWIDTH:v[0-9]+]], {{s[0-9]+}}
+; GCN: v_mov_b32_e32 [[VWIDTH:v[0-9]+]], [[WIDTH]]
 ; GCN: v_bfe_u32 v{{[0-9]+}}, [[SRC]], 0, [[VWIDTH]]
 define amdgpu_kernel void @s_ubfe_sub_i32(i32 addrspace(1)* %out, i32 %src, i32 %width) #1 {
   %id.x = tail call i32 @llvm.amdgcn.workitem.id.x()
@@ -128,7 +128,7 @@
 ; GCN-LABEL: {{^}}s_sbfe_sub_i32:
 ; GCN: s_load_dword [[SRC:s[0-9]+]]
 ; GCN: s_load_dword [[WIDTH:s[0-9]+]]
-; GCN: v_mov_b32_e32 [[VWIDTH:v[0-9]+]], {{s[0-9]+}}
+; GCN: v_mov_b32_e32 [[VWIDTH:v[0-9]+]], [[WIDTH]]
 ; GCN: v_bfe_i32 v{{[0-9]+}}, [[SRC]], 0, [[VWIDTH]]
 define amdgpu_kernel void @s_sbfe_sub_i32(i32 addrspace(1)* %out, i32 %src, i32 %width) #1 {
   %id.x = tail call i32 @llvm.amdgcn.workitem.id.x()
Index: test/CodeGen/AMDGPU/ctlz.ll
===================================================================
--- test/CodeGen/AMDGPU/ctlz.ll
+++ test/CodeGen/AMDGPU/ctlz.ll
@@ -135,7 +135,6 @@
 }
 
 ; FUNC-LABEL: {{^}}v_ctlz_i64:
-; GCN-DAG: v_mov_b32_e32 v[[CTLZ_HI:[0-9]+]], 0{{$}}
 ; GCN-DAG: {{buffer|flat}}_load_dwordx2 v{{\[}}[[LO:[0-9]+]]:[[HI:[0-9]+]]{{\]}}
 ; GCN-DAG: v_cmp_eq_u32_e64 [[CMPHI:s\[[0-9]+:[0-9]+\]]], 0, v[[HI]]
 ; GCN-DAG: v_ffbh_u32_e32 [[FFBH_LO:v[0-9]+]], v[[LO]]
@@ -145,7 +144,7 @@
 ; GCN-DAG: v_or_b32_e32 [[OR:v[0-9]+]], v[[HI]], v[[LO]]
 ; GCN-DAG: v_cmp_ne_u32_e32 vcc, 0, [[OR]]
 ; GCN-DAG: v_cndmask_b32_e32 v[[CLTZ_LO:[0-9]+]], 64, v[[CTLZ:[0-9]+]], vcc
-; GCN: {{buffer|flat}}_store_dwordx2 {{.*}}v{{\[}}[[CLTZ_LO]]:[[CTLZ_HI]]{{\]}}
+; GCN: {{buffer|flat}}_store_dwordx2 {{.*}}v{{\[}}[[CLTZ_LO]]:[[CTLZ_HI:[0-9]+]]{{\]}}
 define amdgpu_kernel void @v_ctlz_i64(i64 addrspace(1)* noalias %out, i64 addrspace(1)* noalias %in) nounwind {
   %tid = call i32 @llvm.r600.read.tidig.x()
   %in.gep = getelementptr i64, i64 addrspace(1)* %in, i32 %tid
Index: test/CodeGen/AMDGPU/ctlz_zero_undef.ll
===================================================================
--- test/CodeGen/AMDGPU/ctlz_zero_undef.ll
+++ test/CodeGen/AMDGPU/ctlz_zero_undef.ll
@@ -121,8 +121,7 @@
 ; GCN-DAG: v_add_i32_e32 [[ADD:v[0-9]+]], vcc, 32, [[FFBH_LO]]
 ; GCN-DAG: v_ffbh_u32_e32 [[FFBH_HI:v[0-9]+]], v[[HI]]
 ; GCN-DAG: v_cndmask_b32_e64 v[[CTLZ:[0-9]+]], [[FFBH_HI]], [[FFBH_LO]]
-; GCN-DAG: v_mov_b32_e32 v[[CTLZ_HI:[0-9]+]], 0{{$}}
-; GCN: {{buffer|flat}}_store_dwordx2 {{.*}}v{{\[}}[[CTLZ]]:[[CTLZ_HI]]{{\]}}
+; GCN: {{buffer|flat}}_store_dwordx2 {{.*}}v{{\[}}[[CTLZ]]:[[CTLZ_HI:[0-9]+]]{{\]}}
 define amdgpu_kernel void @v_ctlz_zero_undef_i64(i64 addrspace(1)* noalias %out, i64 addrspace(1)* noalias %in) nounwind {
   %tid = call i32 @llvm.r600.read.tidig.x()
   %in.gep = getelementptr i64, i64 addrspace(1)* %in, i32 %tid
Index: test/CodeGen/AMDGPU/ds_write2.ll
===================================================================
--- test/CodeGen/AMDGPU/ds_write2.ll
+++ test/CodeGen/AMDGPU/ds_write2.ll
@@ -266,8 +266,8 @@
 }
 
 ; SI-LABEL: @simple_write2_one_val_f64
-; SI: buffer_load_dwordx2 [[VAL:v\[[0-9]+:[0-9]+\]]],
-; SI: v_lshlrev_b32_e32 [[VPTR:v[0-9]+]], 3, v{{[0-9]+}}
+; SI-DAG: buffer_load_dwordx2 [[VAL:v\[[0-9]+:[0-9]+\]]],
+; SI-DAG: v_lshlrev_b32_e32 [[VPTR:v[0-9]+]], 3, v{{[0-9]+}}
 ; SI: ds_write2_b64 [[VPTR]], [[VAL]], [[VAL]] offset1:8
 ; SI: s_endpgm
 define amdgpu_kernel void @simple_write2_one_val_f64(double addrspace(1)* %C, double addrspace(1)* %in) #0 {
Index: test/CodeGen/AMDGPU/fmed3.ll
===================================================================
--- test/CodeGen/AMDGPU/fmed3.ll
+++ test/CodeGen/AMDGPU/fmed3.ll
@@ -845,10 +845,10 @@
 ; GCN: {{buffer_|flat_}}load_dword [[A:v[0-9]+]]
 ; GCN: {{buffer_|flat_}}load_dword [[B:v[0-9]+]]
 ; GCN: {{buffer_|flat_}}load_dword [[C:v[0-9]+]]
-; GCN: v_min_f32
-; GCN: v_max_f32
-; GCN: v_min_f32
-; GCN: v_max_f32
+; GCN-DAG: v_min_f32
+; GCN-DAG: v_max_f32
+; GCN-DAG: v_min_f32
+; GCN-DAG: v_max_f32
 define amdgpu_kernel void @v_test_global_nnans_med3_f32_pat0_srcmod0_mismatch(float addrspace(1)* %out, float addrspace(1)* %aptr, float addrspace(1)* %bptr, float addrspace(1)* %cptr) #2 {
   %tid = call i32 @llvm.amdgcn.workitem.id.x()
   %gep0 = getelementptr float, float addrspace(1)* %aptr, i32 %tid
Index: test/CodeGen/AMDGPU/llvm.amdgcn.atomic.dec.ll
===================================================================
--- test/CodeGen/AMDGPU/llvm.amdgcn.atomic.dec.ll
+++ test/CodeGen/AMDGPU/llvm.amdgcn.atomic.dec.ll
@@ -356,6 +356,7 @@
 
 ; GCN-LABEL: {{^}}global_atomic_dec_ret_i64_offset_addr64:
 ; GCN: v_mov_b32_e32 v[[KLO:[0-9]+]], 42
+; CI: v_mov_b32_e32 v{{[0-9]+}}, 0{{$}}
 ; GCN: v_mov_b32_e32 v[[KHI:[0-9]+]], 0{{$}}
 ; CI: buffer_atomic_dec_x2 v{{\[}}[[KLO]]:[[KHI]]{{\]}}, v{{\[[0-9]+:[0-9]+\]}}, s{{\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:40 glc{{$}}
 ; VI: flat_atomic_dec_x2 v{{\[[0-9]+:[0-9]+\]}}, v{{\[[0-9]+:[0-9]+\]}}, v{{\[}}[[KLO]]:[[KHI]]{{\]}} glc{{$}}
@@ -371,6 +372,7 @@
 
 ; GCN-LABEL: {{^}}global_atomic_dec_noret_i64_offset_addr64:
 ; GCN: v_mov_b32_e32 v[[KLO:[0-9]+]], 42
+; CI: v_mov_b32_e32 v{{[0-9]+}}, 0{{$}}
 ; GCN: v_mov_b32_e32 v[[KHI:[0-9]+]], 0{{$}}
 ; CI: buffer_atomic_dec_x2 v{{\[}}[[KLO]]:[[KHI]]{{\]}}, v{{\[[0-9]+:[0-9]+\]}}, s{{\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:40{{$}}
 ; VI: flat_atomic_dec_x2 v{{\[[0-9]+:[0-9]+\]}}, v{{\[}}[[KLO]]:[[KHI]]{{\]}}{{$}}
Index: test/CodeGen/AMDGPU/llvm.amdgcn.atomic.inc.ll
===================================================================
--- test/CodeGen/AMDGPU/llvm.amdgcn.atomic.inc.ll
+++ test/CodeGen/AMDGPU/llvm.amdgcn.atomic.inc.ll
@@ -207,6 +207,7 @@
 
 ; GCN-LABEL: {{^}}global_atomic_inc_ret_i64_offset_addr64:
 ; GCN: v_mov_b32_e32 v[[KLO:[0-9]+]], 42
+; CI: v_mov_b32_e32 v{{[0-9]+}}, 0{{$}}
 ; GCN: v_mov_b32_e32 v[[KHI:[0-9]+]], 0{{$}}
 ; CI: buffer_atomic_inc_x2 v{{\[}}[[KLO]]:[[KHI]]{{\]}}, v{{\[[0-9]+:[0-9]+\]}}, s{{\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:40 glc{{$}}
 ; VI: flat_atomic_inc_x2 v{{\[[0-9]+:[0-9]+\]}}, v{{\[[0-9]+:[0-9]+\]}}, v{{\[}}[[KLO]]:[[KHI]]{{\]}} glc{{$}}
@@ -222,6 +223,7 @@
 
 ; GCN-LABEL: {{^}}global_atomic_inc_noret_i64_offset_addr64:
 ; GCN: v_mov_b32_e32 v[[KLO:[0-9]+]], 42
+; CI: v_mov_b32_e32 v{{[0-9]+}}, 0{{$}}
 ; GCN: v_mov_b32_e32 v[[KHI:[0-9]+]], 0{{$}}
 ; CI: buffer_atomic_inc_x2 v{{\[}}[[KLO]]:[[KHI]]{{\]}}, v{{\[[0-9]+:[0-9]+\]}}, s{{\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:40{{$}}
 ; VI: flat_atomic_inc_x2 v{{\[[0-9]+:[0-9]+\]}}, v{{\[}}[[KLO]]:[[KHI]]{{\]}}{{$}}
Index: test/CodeGen/AMDGPU/lshl64-to-32.ll
===================================================================
--- /dev/null
+++ test/CodeGen/AMDGPU/lshl64-to-32.ll
@@ -0,0 +1,45 @@
+; RUN: llc -march=amdgcn < %s | FileCheck %s
+
+; CHECK-LABEL: {{^}}zext_shl64_to_32:
+; CHECK: s_lshl_b32
+; CHECK-NOT: s_lshl_b64
+define amdgpu_kernel void @zext_shl64_to_32(i64 addrspace(1)* nocapture %out, i32 %x) {
+  %and = and i32 %x, 1073741823
+  %ext = zext i32 %and to i64
+  %shl = shl i64 %ext, 2
+  store i64 %shl, i64 addrspace(1)* %out, align 4
+  ret void
+}
+
+; CHECK-LABEL: {{^}}sext_shl64_to_32:
+; CHECK: s_lshl_b32
+; CHECK-NOT: s_lshl_b64
+define amdgpu_kernel void @sext_shl64_to_32(i64 addrspace(1)* nocapture %out, i32 %x) {
+  %and = and i32 %x, 536870911
+  %ext = sext i32 %and to i64
+  %shl = shl i64 %ext, 2
+  store i64 %shl, i64 addrspace(1)* %out, align 4
+  ret void
+}
+
+; CHECK-LABEL: {{^}}zext_shl64_overflow:
+; CHECK: s_lshl_b64
+; CHECK-NOT: s_lshl_b32
+define amdgpu_kernel void @zext_shl64_overflow(i64 addrspace(1)* nocapture %out, i32 %x) {
+  %and = and i32 %x, 2147483647
+  %ext = zext i32 %and to i64
+  %shl = shl i64 %ext, 2
+  store i64 %shl, i64 addrspace(1)* %out, align 4
+  ret void
+}
+
+; CHECK-LABEL: {{^}}sext_shl64_overflow:
+; CHECK: s_lshl_b64
+; CHECK-NOT: s_lshl_b32
+define amdgpu_kernel void @sext_shl64_overflow(i64 addrspace(1)* nocapture %out, i32 %x) {
+  %and = and i32 %x, 2147483647
+  %ext = sext i32 %and to i64
+  %shl = shl i64 %ext, 2
+  store i64 %shl, i64 addrspace(1)* %out, align 4
+  ret void
+}
Index: test/CodeGen/AMDGPU/shift-and-i64-ubfe.ll
===================================================================
--- test/CodeGen/AMDGPU/shift-and-i64-ubfe.ll
+++ test/CodeGen/AMDGPU/shift-and-i64-ubfe.ll
@@ -299,10 +299,10 @@
 }
 
 ; GCN-LABEL: {{^}}and_not_mask_i64:
-; GCN: buffer_load_dwordx2 v{{\[}}[[VALLO:[0-9]+]]:[[VALHI:[0-9]+]]{{\]}}
-; GCN: v_mov_b32_e32 v[[SHRHI]], 0{{$}}
+; GCN-DAG: buffer_load_dwordx2 v{{\[}}[[VALLO:[0-9]+]]:[[VALHI:[0-9]+]]{{\]}}
+; GCN: v_mov_b32_e32 v[[SHRHI:[0-9]+]], 0{{$}}
 ; GCN: v_lshrrev_b32_e32 [[SHR:v[0-9]+]], 20, v[[VALLO]]
-; GCN-DAG: v_and_b32_e32 v[[SHRLO]], 4, [[SHR]]
+; GCN-DAG: v_and_b32_e32 v[[SHRLO:[0-9]+]], 4, [[SHR]]
 ; GCN-NOT: v[[SHRLO]]
 ; GCN-NOT: v[[SHRHI]]
 ; GCN: buffer_store_dwordx2 v{{\[}}[[SHRLO]]:[[SHRHI]]{{\]}}
@@ -360,10 +360,9 @@
 }
 
 ; GCN-LABEL: {{^}}v_uextract_bit_33_36_use_upper_half_shift_i64:
-; GCN: buffer_load_dword [[VAL:v[0-9]+]], v{{\[[0-9]+:[0-9]+\]}}, s{{\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:4{{$}}
+; GCN-DAG: buffer_load_dword [[VAL:v[0-9]+]], v{{\[[0-9]+:[0-9]+\]}}, s{{\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:4{{$}}
 ; GCN-DAG: v_bfe_u32 v[[BFE:[0-9]+]], [[VAL]], 1, 3
-; GCN-DAG: v_mov_b32_e32 v[[ZERO:[0-9]+]], 0{{$}}
-; GCN: buffer_store_dwordx2 v{{\[}}[[BFE]]:[[ZERO]]{{\]}}
+; GCN: buffer_store_dwordx2 v{{\[}}[[BFE]]:{{[0-9]+\]}}
 ; GCN: buffer_store_dword v[[ZERO]]
 define amdgpu_kernel void @v_uextract_bit_33_36_use_upper_half_shift_i64(i64 addrspace(1)* %out0, i32 addrspace(1)* %out1, i64 addrspace(1)* %in) #1 {
   %id.x = tail call i32 @llvm.amdgcn.workitem.id.x()
Index: test/CodeGen/AMDGPU/srl.ll
===================================================================
--- test/CodeGen/AMDGPU/srl.ll
+++ test/CodeGen/AMDGPU/srl.ll
@@ -201,7 +201,8 @@
 
 ; GCN-LABEL: {{^}}v_lshr_32_i64:
 ; GCN-DAG: buffer_load_dword v[[HI_A:[0-9]+]], v{{\[[0-9]+:[0-9]+\]}}, s{{\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:4
-; GCN-DAG: v_mov_b32_e32 v[[VHI:[0-9]+]], 0{{$}}
+; GCN-DAG: v_mov_b32_e32 v[[VHI1:[0-9]+]], 0{{$}}
+; GCN-DAG: v_mov_b32_e32 v[[VHI:[0-9]+]], v[[VHI1]]{{$}}
 ; GCN: buffer_store_dwordx2 v{{\[}}[[HI_A]]:[[VHI]]{{\]}}
 define amdgpu_kernel void @v_lshr_32_i64(i64 addrspace(1)* %out, i64 addrspace(1)* %in) {
   %tid = call i32 @llvm.r600.read.tidig.x() #0
Index: test/CodeGen/AMDGPU/sub.i16.ll
===================================================================
--- test/CodeGen/AMDGPU/sub.i16.ll
+++ test/CodeGen/AMDGPU/sub.i16.ll
@@ -85,9 +85,9 @@
 
 ; FIXME: Need to handle non-uniform case for function below (load without gep).
 ; GCN-LABEL: {{^}}v_test_sub_i16_zext_to_i64:
-; VI-DAG: v_mov_b32_e32 v[[VZERO:[0-9]+]], 0
 ; VI: flat_load_ushort [[A:v[0-9]+]]
 ; VI: flat_load_ushort [[B:v[0-9]+]]
+; VI-DAG: v_mov_b32_e32 v[[VZERO:[0-9]+]], 0
 ; VI-DAG: v_subrev_u16_e32 v[[ADD:[0-9]+]], [[B]], [[A]]
 ; VI: buffer_store_dwordx2 v{{\[}}[[ADD]]:[[VZERO]]{{\]}}, off, {{s\[[0-9]+:[0-9]+\]}}, 0{{$}}
 define amdgpu_kernel void @v_test_sub_i16_zext_to_i64(i64 addrspace(1)* %out, i16 addrspace(1)* %in0, i16 addrspace(1)* %in1) #1 {