Index: lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp
===================================================================
--- lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp
+++ lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp
@@ -89,9 +89,15 @@
   setAction({G_CONSTANT, S1}, Legal);
 
   getActionDefinitionsBuilder(
-    { G_FADD, G_FMUL })
+    { G_FADD, G_FMUL, G_FNEG, G_FABS})
     .legalFor({S32, S64});
 
+  // Use actual fsub instruction
+  setAction({G_FSUB, S32}, Legal);
+
+  // Must use fadd + fneg
+  setAction({G_FSUB, S64}, Lower);
+
   setAction({G_FCMP, S1}, Legal);
   setAction({G_FCMP, 1, S32}, Legal);
   setAction({G_FCMP, 1, S64}, Legal);
Index: lib/Target/AMDGPU/AMDGPURegisterBankInfo.cpp
===================================================================
--- lib/Target/AMDGPU/AMDGPURegisterBankInfo.cpp
+++ lib/Target/AMDGPU/AMDGPURegisterBankInfo.cpp
@@ -410,7 +410,9 @@
   case AMDGPU::G_CTTZ:
   case AMDGPU::G_CTTZ_ZERO_UNDEF:
   case AMDGPU::G_CTPOP:
-  case AMDGPU::G_BSWAP: {
+  case AMDGPU::G_BSWAP:
+  case AMDGPU::G_FABS:
+  case AMDGPU::G_FNEG: {
     unsigned Size = MRI.getType(MI.getOperand(0).getReg()).getSizeInBits();
     unsigned BankID = getRegBankID(MI.getOperand(1).getReg(), MRI, *TRI);
     OpdsMapping[0] = OpdsMapping[1] = AMDGPU::getValueMapping(BankID, Size);
Index: test/CodeGen/AMDGPU/GlobalISel/legalize-fabs.mir
===================================================================
--- /dev/null
+++ test/CodeGen/AMDGPU/GlobalISel/legalize-fabs.mir
@@ -0,0 +1,26 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=fiji -run-pass=legalizer -global-isel %s -o - | FileCheck  %s
+
+---
+name: test_fabs_f32
+body: |
+  bb.0:
+    liveins: $vgpr0
+
+    ; CHECK-LABEL: name: test_fabs_f32
+    ; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY $vgpr0
+    %0:_(s32) = COPY $vgpr0
+    %1:_(s32) = G_FABS %0
+...
+---
+name: test_fabs_f64
+body: |
+  bb.0:
+    liveins: $vgpr0
+
+    ; CHECK-LABEL: name: test_fabs_f64
+    ; CHECK: [[COPY:%[0-9]+]]:_(s64) = COPY $vgpr0_vgpr1
+    %0:_(s64) = COPY $vgpr0_vgpr1
+    %1:_(s64) = G_FABS %0
+...
+
Index: test/CodeGen/AMDGPU/GlobalISel/legalize-fneg.mir
===================================================================
--- /dev/null
+++ test/CodeGen/AMDGPU/GlobalISel/legalize-fneg.mir
@@ -0,0 +1,26 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=fiji -run-pass=legalizer -global-isel %s -o - | FileCheck  %s
+
+---
+name: test_fneg_f32
+body: |
+  bb.0:
+    liveins: $vgpr0
+
+    ; CHECK-LABEL: name: test_fneg_f32
+    ; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY $vgpr0
+    %0:_(s32) = COPY $vgpr0
+    %1:_(s32) = G_FNEG %0
+...
+---
+name: test_fneg_f64
+body: |
+  bb.0:
+    liveins: $vgpr0
+
+    ; CHECK-LABEL: name: test_fneg_f64
+    ; CHECK: [[COPY:%[0-9]+]]:_(s64) = COPY $vgpr0_vgpr1
+    %0:_(s64) = COPY $vgpr0_vgpr1
+    %1:_(s64) = G_FNEG %0
+...
+
Index: test/CodeGen/AMDGPU/GlobalISel/legalize-fsub.mir
===================================================================
--- /dev/null
+++ test/CodeGen/AMDGPU/GlobalISel/legalize-fsub.mir
@@ -0,0 +1,36 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=amdgcn-mesa-mesa3d -mcpu=fiji -run-pass=legalizer %s -o - | FileCheck %s
+
+---
+name: test_fsub_f32
+body: |
+  bb.0:
+    liveins: $vgpr0, $vgpr1
+
+    ; CHECK-LABEL: name: test_fsub_f32
+    ; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY $vgpr0
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s32) = COPY $vgpr1
+    ; CHECK: [[FSUB:%[0-9]+]]:_(s32) = G_FSUB [[COPY]], [[COPY1]]
+    ; CHECK: $vgpr0 = COPY [[FSUB]](s32)
+    %0:_(s32) = COPY $vgpr0
+    %1:_(s32) = COPY $vgpr1
+    %2:_(s32) = G_FSUB %0, %1
+    $vgpr0 = COPY %2
+...
+---
+name: test_fsub_f64
+body: |
+  bb.0:
+    liveins: $vgpr0_vgpr1, $vgpr2_vgpr3
+
+    ; CHECK-LABEL: name: test_fsub_f64
+    ; CHECK: [[COPY:%[0-9]+]]:_(s64) = COPY $vgpr0_vgpr1
+    ; CHECK: [[COPY1:%[0-9]+]]:_(s64) = COPY $vgpr2_vgpr3
+    ; CHECK: [[FNEG:%[0-9]+]]:_(s64) = G_FNEG [[COPY1]]
+    ; CHECK: [[FADD:%[0-9]+]]:_(s64) = G_FADD [[COPY]], [[FNEG]]
+    ; CHECK: $vgpr0_vgpr1 = COPY [[FADD]](s64)
+    %0:_(s64) = COPY $vgpr0_vgpr1
+    %1:_(s64) = COPY $vgpr2_vgpr3
+    %2:_(s64) = G_FSUB %0, %1
+    $vgpr0_vgpr1 = COPY %2
+...
Index: test/CodeGen/AMDGPU/GlobalISel/regbankselect-fabs.mir
===================================================================
--- /dev/null
+++ test/CodeGen/AMDGPU/GlobalISel/regbankselect-fabs.mir
@@ -0,0 +1,35 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -march=amdgcn -run-pass=regbankselect %s -verify-machineinstrs -o - -regbankselect-fast | FileCheck %s
+# RUN: llc -march=amdgcn -run-pass=regbankselect %s -verify-machineinstrs -o - -regbankselect-greedy | FileCheck %s
+
+---
+name: fabs_s
+legalized: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0_sgpr1
+    ; CHECK-LABEL: name: fabs_s
+    ; CHECK: [[COPY:%[0-9]+]]:sgpr(s32) = COPY $sgpr0
+    ; CHECK: [[FABS:%[0-9]+]]:sgpr(s32) = G_FABS [[COPY]]
+    ; CHECK: $vgpr0 = COPY [[FABS]](s32)
+    %0:_(s32) = COPY $sgpr0
+    %1:_(s32) = G_FABS %0
+    $vgpr0 = COPY %1
+...
+
+---
+name: fabs_v
+legalized: true
+
+body: |
+  bb.0:
+    liveins: $vgpr0_vgpr1
+    ; CHECK-LABEL: name: fabs_v
+    ; CHECK: [[COPY:%[0-9]+]]:vgpr(s32) = COPY $vgpr0
+    ; CHECK: [[FABS:%[0-9]+]]:vgpr(s32) = G_FABS [[COPY]]
+    ; CHECK: $vgpr0 = COPY [[FABS]](s32)
+    %0:_(s32) = COPY $vgpr0
+    %1:_(s32) = G_FABS %0
+    $vgpr0 = COPY %1
+...
Index: test/CodeGen/AMDGPU/GlobalISel/regbankselect-fneg.mir
===================================================================
--- /dev/null
+++ test/CodeGen/AMDGPU/GlobalISel/regbankselect-fneg.mir
@@ -0,0 +1,35 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -march=amdgcn -run-pass=regbankselect %s -verify-machineinstrs -o - -regbankselect-fast | FileCheck %s
+# RUN: llc -march=amdgcn -run-pass=regbankselect %s -verify-machineinstrs -o - -regbankselect-greedy | FileCheck %s
+
+---
+name: fneg_s
+legalized: true
+
+body: |
+  bb.0:
+    liveins: $sgpr0_sgpr1
+    ; CHECK-LABEL: name: fneg_s
+    ; CHECK: [[COPY:%[0-9]+]]:sgpr(s32) = COPY $sgpr0
+    ; CHECK: [[FNEG:%[0-9]+]]:sgpr(s32) = G_FNEG [[COPY]]
+    ; CHECK: $vgpr0 = COPY [[FNEG]](s32)
+    %0:_(s32) = COPY $sgpr0
+    %1:_(s32) = G_FNEG %0
+    $vgpr0 = COPY %1
+...
+
+---
+name: fneg_v
+legalized: true
+
+body: |
+  bb.0:
+    liveins: $vgpr0_vgpr1
+    ; CHECK-LABEL: name: fneg_v
+    ; CHECK: [[COPY:%[0-9]+]]:vgpr(s32) = COPY $vgpr0
+    ; CHECK: [[FNEG:%[0-9]+]]:vgpr(s32) = G_FNEG [[COPY]]
+    ; CHECK: $vgpr0 = COPY [[FNEG]](s32)
+    %0:_(s32) = COPY $vgpr0
+    %1:_(s32) = G_FNEG %0
+    $vgpr0 = COPY %1
+...