Index: lib/Target/AMDGPU/SIShrinkInstructions.cpp
===================================================================
--- lib/Target/AMDGPU/SIShrinkInstructions.cpp
+++ lib/Target/AMDGPU/SIShrinkInstructions.cpp
@@ -226,6 +226,30 @@
         continue;
       }
 
+      if (MI.getOpcode() == AMDGPU::V_MOV_B32_e32) {
+        // If this has a literal constant source that is the same as the
+        // reversed bits reversed of an inline immediate, replace with a
+        // bitreverse of that constant. This saves 4 bytes in the common case of
+        // materializing sign bits.
+
+        // Test if we are after regalloc. We only want to do this after any
+        // optimizations happen because this will confuse them.
+        // XXX - not exactly a check for post-regalloc run.
+        MachineOperand &Src = MI.getOperand(1);
+        if (Src.isImm() &&
+            TargetRegisterInfo::isPhysicalRegister(MI.getOperand(0).getReg())) {
+          int64_t Imm = Src.getImm();
+          if (isInt<32>(Imm) && !TII->isInlineConstant(Src, 4)) {
+            int32_t ReverseImm = reverseBits<int32_t>(static_cast<int32_t>(Imm));
+            if (ReverseImm >= -16 && ReverseImm <= 64) {
+              MI.setDesc(TII->get(AMDGPU::V_BFREV_B32_e32));
+              Src.setImm(ReverseImm);
+              continue;
+            }
+          }
+        }
+      }
+
       if (!TII->hasVALU32BitEncoding(MI.getOpcode()))
         continue;
 
Index: test/CodeGen/AMDGPU/bitreverse-inline-immediates.ll
===================================================================
--- /dev/null
+++ test/CodeGen/AMDGPU/bitreverse-inline-immediates.ll
@@ -0,0 +1,158 @@
+; RUN: llc -march=amdgcn -verify-machineinstrs < %s | FileCheck -check-prefix=GCN %s
+
+; Test that materialization constants that are the bit reversed of
+; inline immediates are replaced with bfrev of the inline immediate to
+; save code size.
+
+; GCN-LABEL: {{^}}materialize_0_i32:
+; GCN: v_mov_b32_e32 [[K:v[0-9]+]], 0{{$}}
+; GCN: buffer_store_dword [[K]]
+define void @materialize_0_i32(i32 addrspace(1)* %out) {
+  store i32 0, i32 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_0_i64:
+; GCN: v_mov_b32_e32 v[[LOK:[0-9]+]], 0{{$}}
+; GCN: v_mov_b32_e32 v[[HIK:[0-9]+]], 0{{$}}
+; GCN: buffer_store_dwordx2 v{{\[}}[[LOK]]:[[HIK]]{{\]}}
+define void @materialize_0_i64(i64 addrspace(1)* %out) {
+  store i64 0, i64 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_neg1_i32:
+; GCN: v_mov_b32_e32 [[K:v[0-9]+]], -1{{$}}
+; GCN: buffer_store_dword [[K]]
+define void @materialize_neg1_i32(i32 addrspace(1)* %out) {
+  store i32 -1, i32 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_neg1_i64:
+; GCN: v_mov_b32_e32 v[[LOK:[0-9]+]], -1{{$}}
+; GCN: v_mov_b32_e32 v[[HIK:[0-9]+]], -1{{$}}
+; GCN: buffer_store_dwordx2 v{{\[}}[[LOK]]:[[HIK]]{{\]}}
+define void @materialize_neg1_i64(i64 addrspace(1)* %out) {
+  store i64 -1, i64 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_signbit_i32:
+; GCN: v_bfrev_b32_e32 [[K:v[0-9]+]], 1{{$}}
+; GCN: buffer_store_dword [[K]]
+define void @materialize_signbit_i32(i32 addrspace(1)* %out) {
+  store i32 -2147483648, i32 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_signbit_i64:
+; GCN-DAG: v_mov_b32_e32 v[[LOK:[0-9]+]], 0{{$}}
+; GCN-DAG: v_bfrev_b32_e32 v[[HIK:[0-9]+]], 1{{$}}
+; GCN: buffer_store_dwordx2 v{{\[}}[[LOK]]:[[HIK]]{{\]}}
+define void @materialize_signbit_i64(i64 addrspace(1)* %out) {
+  store i64  -9223372036854775808, i64 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_rev_neg16_i32:
+; GCN: v_bfrev_b32_e32 [[K:v[0-9]+]], -16{{$}}
+; GCN: buffer_store_dword [[K]]
+define void @materialize_rev_neg16_i32(i32 addrspace(1)* %out) {
+  store i32 268435455, i32 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_rev_neg16_i64:
+; GCN-DAG: v_mov_b32_e32 v[[LOK:[0-9]+]], -1{{$}}
+; GCN-DAG: v_bfrev_b32_e32 v[[HIK:[0-9]+]], -16{{$}}
+; GCN: buffer_store_dwordx2 v{{\[}}[[LOK]]:[[HIK]]{{\]}}
+define void @materialize_rev_neg16_i64(i64 addrspace(1)* %out) {
+  store i64  1152921504606846975, i64 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_rev_neg17_i32:
+; GCN: v_mov_b32_e32 [[K:v[0-9]+]], 0xf7ffffff{{$}}
+; GCN: buffer_store_dword [[K]]
+define void @materialize_rev_neg17_i32(i32 addrspace(1)* %out) {
+  store i32 -134217729, i32 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_rev_neg17_i64:
+; GCN-DAG: v_mov_b32_e32 v[[LOK:[0-9]+]], -1{{$}}
+; GCN-DAG: v_mov_b32_e32 v[[HIK:[0-9]+]], 0xf7ffffff{{$}}
+; GCN: buffer_store_dwordx2 v{{\[}}[[LOK]]:[[HIK]]{{\]}}
+define void @materialize_rev_neg17_i64(i64 addrspace(1)* %out) {
+  store i64 -576460752303423489, i64 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_rev_64_i32:
+; GCN: v_bfrev_b32_e32 [[K:v[0-9]+]], 64{{$}}
+; GCN: buffer_store_dword [[K]]
+define void @materialize_rev_64_i32(i32 addrspace(1)* %out) {
+  store i32 33554432, i32 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_rev_64_i64:
+; GCN-DAG: v_mov_b32_e32 v[[LOK:[0-9]+]], 0{{$}}
+; GCN-DAG: v_bfrev_b32_e32 v[[HIK:[0-9]+]], 64{{$}}
+; GCN: buffer_store_dwordx2 v{{\[}}[[LOK]]:[[HIK]]{{\]}}
+define void @materialize_rev_64_i64(i64 addrspace(1)* %out) {
+  store i64 144115188075855872, i64 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_rev_65_i32:
+; GCN: v_mov_b32_e32 [[K:v[0-9]+]], 0x82000000{{$}}
+; GCN: buffer_store_dword [[K]]
+define void @materialize_rev_65_i32(i32 addrspace(1)* %out) {
+  store i32 -2113929216, i32 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_rev_65_i64:
+; GCN-DAG: v_mov_b32_e32 v[[LOK:[0-9]+]], 0{{$}}
+; GCN-DAG: v_mov_b32_e32 v[[HIK:[0-9]+]], 0x82000000{{$}}
+; GCN: buffer_store_dwordx2 v{{\[}}[[LOK]]:[[HIK]]{{\]}}
+define void @materialize_rev_65_i64(i64 addrspace(1)* %out) {
+  store i64 -9079256848778919936, i64 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_rev_3_i32:
+; GCN: v_mov_b32_e32 [[K:v[0-9]+]], -2.0{{$}}
+; GCN: buffer_store_dword [[K]]
+define void @materialize_rev_3_i32(i32 addrspace(1)* %out) {
+  store i32 -1073741824, i32 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_rev_3_i64:
+; GCN-DAG: v_mov_b32_e32 v[[LOK:[0-9]+]], 0{{$}}
+; GCN-DAG: v_mov_b32_e32 v[[HIK:[0-9]+]], -2.0{{$}}
+; GCN: buffer_store_dwordx2 v{{\[}}[[LOK]]:[[HIK]]{{\]}}
+define void @materialize_rev_3_i64(i64 addrspace(1)* %out) {
+  store i64 -4611686018427387904, i64 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_rev_1.0_i32:
+; GCN: v_mov_b32_e32 [[K:v[0-9]+]], 0x1fc{{$}}
+; GCN: buffer_store_dword [[K]]
+define void @materialize_rev_1.0_i32(i32 addrspace(1)* %out) {
+  store i32 508, i32 addrspace(1)* %out
+  ret void
+}
+
+; GCN-LABEL: {{^}}materialize_rev_1.0_i64:
+; GCN-DAG: v_mov_b32_e32 v[[LOK:[0-9]+]], 0x1fc{{$}}
+; GCN-DAG: v_mov_b32_e32 v[[HIK:[0-9]+]], 0{{$}}
+; GCN: buffer_store_dwordx2 v{{\[}}[[LOK]]:[[HIK]]{{\]}}
+define void @materialize_rev_1.0_i64(i64 addrspace(1)* %out) {
+  store i64 508, i64 addrspace(1)* %out
+  ret void
+}
Index: test/CodeGen/AMDGPU/fmaxnum.ll
===================================================================
--- test/CodeGen/AMDGPU/fmaxnum.ll
+++ test/CodeGen/AMDGPU/fmaxnum.ll
@@ -1,5 +1,5 @@
-; RUN: llc -march=amdgcn -mcpu=SI < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
-; RUN: llc -march=amdgcn -mcpu=tonga < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
+; RUN: llc -march=amdgcn -verify-machineinstrs < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
+; RUN: llc -march=amdgcn -mcpu=tonga -verify-machineinstrs < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
 
 declare float @llvm.maxnum.f32(float, float) #0
 declare <2 x float> @llvm.maxnum.v2f32(<2 x float>, <2 x float>) #0
@@ -207,7 +207,7 @@
 
 ; FUNC-LABEL: @constant_fold_fmax_f32_n0_p0
 ; SI-NOT: v_max_f32_e32
-; SI: v_mov_b32_e32 [[REG:v[0-9]+]], 0x80000000
+; SI: v_bfrev_b32_e32 [[REG:v[0-9]+]], 1{{$}}
 ; SI: buffer_store_dword [[REG]]
 
 ; EG: MEM_RAT_CACHELESS STORE_RAW [[OUT:T[0-9]+\.[XYZW]]]
@@ -221,7 +221,7 @@
 
 ; FUNC-LABEL: @constant_fold_fmax_f32_n0_n0
 ; SI-NOT: v_max_f32_e32
-; SI: v_mov_b32_e32 [[REG:v[0-9]+]], 0x80000000
+; SI: v_bfrev_b32_e32 [[REG:v[0-9]+]], 1{{$}}
 ; SI: buffer_store_dword [[REG]]
 
 ; EG: MEM_RAT_CACHELESS STORE_RAW [[OUT:T[0-9]+\.[XYZW]]]
Index: test/CodeGen/AMDGPU/fminnum.ll
===================================================================
--- test/CodeGen/AMDGPU/fminnum.ll
+++ test/CodeGen/AMDGPU/fminnum.ll
@@ -1,5 +1,5 @@
-; RUN: llc -march=amdgcn -mcpu=SI < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
-; RUN: llc -march=amdgcn -mcpu=tonga < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
+; RUN: llc -march=amdgcn -verify-machineinstrs < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
+; RUN: llc -march=amdgcn -mcpu=tonga -verify-machineinstrs < %s | FileCheck -check-prefix=SI -check-prefix=FUNC %s
 ; RUN: llc -march=r600 -mcpu=cypress < %s | FileCheck -check-prefix=EG -check-prefix=FUNC %s
 
 declare float @llvm.minnum.f32(float, float) #0
@@ -206,7 +206,7 @@
 
 ; FUNC-LABEL: @constant_fold_fmin_f32_n0_p0
 ; SI-NOT: v_min_f32_e32
-; SI: v_mov_b32_e32 [[REG:v[0-9]+]], 0x80000000
+; SI: v_bfrev_b32_e32 [[REG:v[0-9]+]], 1{{$}}
 ; SI: buffer_store_dword [[REG]]
 
 ; EG: MEM_RAT_CACHELESS STORE_RAW [[OUT:T[0-9]+\.[XYZW]]]
@@ -220,7 +220,7 @@
 
 ; FUNC-LABEL: @constant_fold_fmin_f32_n0_n0
 ; SI-NOT: v_min_f32_e32
-; SI: v_mov_b32_e32 [[REG:v[0-9]+]], 0x80000000
+; SI: v_bfrev_b32_e32 [[REG:v[0-9]+]], 1{{$}}
 ; SI: buffer_store_dword [[REG]]
 
 ; EG: MEM_RAT_CACHELESS STORE_RAW [[OUT:T[0-9]+\.[XYZW]]]
Index: test/CodeGen/AMDGPU/fneg-fabs.f64.ll
===================================================================
--- test/CodeGen/AMDGPU/fneg-fabs.f64.ll
+++ test/CodeGen/AMDGPU/fneg-fabs.f64.ll
@@ -44,7 +44,7 @@
 }
 
 ; FUNC-LABEL: {{^}}fneg_fabs_fn_free_f64:
-; SI: v_mov_b32_e32 [[IMMREG:v[0-9]+]], 0x80000000
+; SI: v_bfrev_b32_e32 [[IMMREG:v[0-9]+]], 1{{$}}
 ; SI: v_or_b32_e32 v{{[0-9]+}}, s{{[0-9]+}}, [[IMMREG]]
 define void @fneg_fabs_fn_free_f64(double addrspace(1)* %out, i64 %in) {
   %bc = bitcast i64 %in to double
@@ -57,7 +57,7 @@
 ; FUNC-LABEL: {{^}}fneg_fabs_f64:
 ; SI: s_load_dwordx2 s{{\[}}[[LO_X:[0-9]+]]:[[HI_X:[0-9]+]]{{\]}}
 ; SI: s_load_dwordx2
-; SI: v_mov_b32_e32 [[IMMREG:v[0-9]+]], 0x80000000
+; SI: v_bfrev_b32_e32 [[IMMREG:v[0-9]+]], 1{{$}}
 ; SI-DAG: v_or_b32_e32 v[[HI_V:[0-9]+]], s[[HI_X]], [[IMMREG]]
 ; SI-DAG: v_mov_b32_e32 v[[LO_V:[0-9]+]], s[[LO_X]]
 ; SI: buffer_store_dwordx2 v{{\[}}[[LO_V]]:[[HI_V]]{{\]}}
@@ -69,7 +69,7 @@
 }
 
 ; FUNC-LABEL: {{^}}fneg_fabs_v2f64:
-; SI: v_mov_b32_e32 [[IMMREG:v[0-9]+]], 0x80000000
+; SI: v_bfrev_b32_e32 [[IMMREG:v[0-9]+]], 1{{$}}
 ; SI-NOT: 0x80000000
 ; SI: v_or_b32_e32 v{{[0-9]+}}, s{{[0-9]+}}, [[IMMREG]]
 ; SI: v_or_b32_e32 v{{[0-9]+}}, s{{[0-9]+}}, [[IMMREG]]
@@ -81,7 +81,7 @@
 }
 
 ; FUNC-LABEL: {{^}}fneg_fabs_v4f64:
-; SI: v_mov_b32_e32 [[IMMREG:v[0-9]+]], 0x80000000
+; SI: v_bfrev_b32_e32 [[IMMREG:v[0-9]+]], 1{{$}}
 ; SI-NOT: 0x80000000
 ; SI: v_or_b32_e32 v{{[0-9]+}}, s{{[0-9]+}}, [[IMMREG]]
 ; SI: v_or_b32_e32 v{{[0-9]+}}, s{{[0-9]+}}, [[IMMREG]]
Index: test/CodeGen/AMDGPU/imm.ll
===================================================================
--- test/CodeGen/AMDGPU/imm.ll
+++ test/CodeGen/AMDGPU/imm.ll
@@ -23,7 +23,7 @@
 
 ; CHECK-LABEL: {{^}}store_imm_neg_0.0_i64:
 ; CHECK-DAG: v_mov_b32_e32 v[[LO_VREG:[0-9]+]], 0{{$}}
-; CHECK-DAG: v_mov_b32_e32 v[[HI_VREG:[0-9]+]], 0x80000000
+; CHECK-DAG: v_bfrev_b32_e32 v[[HI_VREG:[0-9]+]], 1{{$}}
 ; CHECK: buffer_store_dwordx2 v{{\[}}[[LO_VREG]]:[[HI_VREG]]{{\]}}
 define void @store_imm_neg_0.0_i64(i64 addrspace(1) *%out) {
   store i64 -9223372036854775808, i64 addrspace(1) *%out
@@ -31,7 +31,7 @@
 }
 
 ; CHECK-LABEL: {{^}}store_inline_imm_neg_0.0_i32:
-; CHECK: v_mov_b32_e32 [[REG:v[0-9]+]], 0x80000000
+; CHECK: v_bfrev_b32_e32 [[REG:v[0-9]+]], 1{{$}}
 ; CHECK: buffer_store_dword [[REG]]
 define void @store_inline_imm_neg_0.0_i32(i32 addrspace(1)* %out) {
   store i32 -2147483648, i32 addrspace(1)* %out
@@ -47,7 +47,7 @@
 }
 
 ; CHECK-LABEL: {{^}}store_imm_neg_0.0_f32:
-; CHECK: v_mov_b32_e32 [[REG:v[0-9]+]], 0x80000000
+; CHECK: v_bfrev_b32_e32 [[REG:v[0-9]+]], 1{{$}}
 ; CHECK: buffer_store_dword [[REG]]
 define void @store_imm_neg_0.0_f32(float addrspace(1)* %out) {
   store float -0.0, float addrspace(1)* %out
@@ -520,7 +520,7 @@
 
 ; CHECK-LABEL: {{^}}store_literal_imm_neg_0.0_f64:
 ; CHECK-DAG: v_mov_b32_e32 v[[LO_VREG:[0-9]+]], 0{{$}}
-; CHECK-DAG: v_mov_b32_e32 v[[HI_VREG:[0-9]+]], 0x80000000
+; CHECK-DAG: v_bfrev_b32_e32 v[[HI_VREG:[0-9]+]], 1{{$}}
 ; CHECK: buffer_store_dwordx2 v{{\[}}[[LO_VREG]]:[[HI_VREG]]{{\]}}
 define void @store_literal_imm_neg_0.0_f64(double addrspace(1)* %out) {
   store double -0.0, double addrspace(1)* %out