[Hexagon] Lowering saturating subtraction

llvm/lib/Target/Hexagon/HexagonISelLoweringHVX.cpp

@@ -208,6 +208,8 @@ HexagonTargetLowering::initializeHVXLowering() {
     setOperationAction(ISD::SPLAT_VECTOR,   T, Legal);
     setOperationAction(ISD::UADDSAT, T, Legal);
     setOperationAction(ISD::SADDSAT, T, Legal);
+    setOperationAction(ISD::USUBSAT, T, Legal);
+    setOperationAction(ISD::SSUBSAT, T, Legal);
     if (T != ByteV) {
       setOperationAction(ISD::SIGN_EXTEND_VECTOR_INREG, T, Legal);
       setOperationAction(ISD::ZERO_EXTEND_VECTOR_INREG, T, Legal);
@@ -302,6 +304,8 @@ HexagonTargetLowering::initializeHVXLowering() {
     setOperationAction(ISD::UADDSAT, T, Legal);
     setOperationAction(ISD::SADDSAT, T, Legal);
     setOperationAction(ISD::SUB,      T, Legal);
+    setOperationAction(ISD::USUBSAT, T, Legal);
+    setOperationAction(ISD::SSUBSAT, T, Legal);
     setOperationAction(ISD::MUL,      T, Custom);
     setOperationAction(ISD::MULHS,    T, Custom);
     setOperationAction(ISD::MULHU,    T, Custom);

llvm/lib/Target/Hexagon/HexagonPatternsHVX.td

@@ -441,6 +441,21 @@ let Predicates = [UseHVX] in {
   def: OpR_RR_pat_sat<V6_vaddwsat_dv,  saddsat, VecPI32, HWI32>;
 }
 
+let Predicates = [UseHVX] in {
+  def: OpR_RR_pat_sat<V6_vsububsat,    usubsat, VecI8,   HVI8>;
+  def: OpR_RR_pat_sat<V6_vsubuhsat,    usubsat, VecI16,  HVI16>;
+  def: OpR_RR_pat_sat<V6_vsubuwsat,    usubsat, VecI32,  HVI32>;
+  def: OpR_RR_pat_sat<V6_vsubbsat,     ssubsat, VecI8,   HVI8>;
+  def: OpR_RR_pat_sat<V6_vsubhsat,     ssubsat, VecI16,  HVI16>;
+  def: OpR_RR_pat_sat<V6_vsubwsat,     ssubsat, VecI32,  HVI32>;
+  def: OpR_RR_pat_sat<V6_vsububsat_dv, usubsat, VecPI8,  HWI8>;
+  def: OpR_RR_pat_sat<V6_vsubuhsat_dv, usubsat, VecPI16, HWI16>;
+  def: OpR_RR_pat_sat<V6_vsubuwsat_dv, usubsat, VecPI32, HWI32>;
+  def: OpR_RR_pat_sat<V6_vsubbsat_dv,  ssubsat, VecPI8,  HWI8>;
+  def: OpR_RR_pat_sat<V6_vsubhsat_dv,  ssubsat, VecPI16, HWI16>;
+  def: OpR_RR_pat_sat<V6_vsubwsat_dv,  ssubsat, VecPI32, HWI32>;
+}
+
 // For now, we always deal with vector floating point in SF mode.
 class OpR_RR_pat_conv<InstHexagon MI, PatFrag Op, ValueType ResType,
                       PatFrag RsPred, PatFrag RtPred = RsPred>

llvm/test/CodeGen/Hexagon/vsubsat.ll

@@ -0,0 +1,99 @@
+; RUN: llc -march=hexagon -mattr=+hvxv73,+hvx-length128b < %s | FileCheck %s
+
+;; Saturating subtraction.
+
+; CHECK-LABEL: vsububsat
+; CHECK: v[[#]].ub = vsub(v[[#]].ub,v[[#]].ub):sat
+define dso_local <128 x i8> @vsububsat(<128 x i8> %x, <128 x i8> %y) {
+entry:
+  %0 = tail call <128 x i8> @llvm.usub.sat.v128i8(<128 x i8> %x, <128 x i8> %y)
+  ret <128 x i8> %0
+}
+
+; CHECK-LABEL: vsubuhsat
+; CHECK: v[[#]].uh = vsub(v[[#]].uh,v[[#]].uh):sat
+define dso_local <64 x i16> @vsubuhsat(<64 x i16> %x, <64 x i16> %y) {
+entry:
+  %0 = tail call <64 x i16> @llvm.usub.sat.v64i16(<64 x i16> %x, <64 x i16> %y)
+  ret <64 x i16> %0
+}
+
+; CHECK-LABEL: vsubuwsat
+; CHECK: v[[#]].uw = vsub(v[[#]].uw,v[[#]].uw):sat
+define dso_local <32 x i32> @vsubuwsat(<32 x i32> %x, <32 x i32> %y) {
+entry:
+  %0 = tail call <32 x i32> @llvm.usub.sat.v32i32(<32 x i32> %x, <32 x i32> %y)
+  ret <32 x i32> %0
+}
+
+; CHECK-LABEL: vsubbsat
+; CHECK: v[[#]].b = vsub(v[[#]].b,v[[#]].b):sat
+define dso_local <128 x i8> @vsubbsat(<128 x i8> %x, <128 x i8> %y) {
+entry:
+  %0 = tail call <128 x i8> @llvm.ssub.sat.v128i8(<128 x i8> %x, <128 x i8> %y)
+  ret <128 x i8> %0
+}
+
+; CHECK-LABEL: vsubhsat
+; CHECK: v[[#]].h = vsub(v[[#]].h,v[[#]].h):sat
+define dso_local <64 x i16> @vsubhsat(<64 x i16> %x, <64 x i16> %y) {
+entry:
+  %0 = tail call <64 x i16> @llvm.ssub.sat.v64i16(<64 x i16> %x, <64 x i16> %y)
+  ret <64 x i16> %0
+}
+
+; CHECK-LABEL: vsubwsat
+; CHECK: v[[#]].w = vsub(v[[#]].w,v[[#]].w):sat
+define dso_local <32 x i32> @vsubwsat(<32 x i32> %x, <32 x i32> %y) {
+entry:
+  %0 = tail call <32 x i32> @llvm.ssub.sat.v32i32(<32 x i32> %x, <32 x i32> %y)
+  ret <32 x i32> %0
+}
+
+; CHECK-LABEL: vsububsat_dv
+; CHECK: v[[#]]:[[#]].ub = vsub(v[[#]]:[[#]].ub,v[[#]]:[[#]].ub):sat
+define dso_local <256 x i8> @vsububsat_dv(<256 x i8> %x, <256 x i8> %y) {
+entry:
+  %0 = tail call <256 x i8> @llvm.usub.sat.v256i8(<256 x i8> %x, <256 x i8> %y)
+  ret <256 x i8> %0
+}
+
+; CHECK-LABEL: vsubuhsat_dv
+; CHECK: v[[#]]:[[#]].uh = vsub(v[[#]]:[[#]].uh,v[[#]]:[[#]].uh):sat
+define dso_local <128 x i16> @vsubuhsat_dv(<128 x i16> %x, <128 x i16> %y) {
+entry:
+  %0 = tail call <128 x i16> @llvm.usub.sat.v128i16(<128 x i16> %x, <128 x i16> %y)
+  ret <128 x i16> %0
+}
+
+; CHECK-LABEL: vsubuwsat_dv
+; CHECK: v[[#]]:[[#]].uw = vsub(v[[#]]:[[#]].uw,v[[#]]:[[#]].uw):sat
+define dso_local <64 x i32> @vsubuwsat_dv(<64 x i32> %x, <64 x i32> %y) {
+entry:
+  %0 = tail call <64 x i32> @llvm.usub.sat.v64i32(<64 x i32> %x, <64 x i32> %y)
+  ret <64 x i32> %0
+}
+
+; CHECK-LABEL: vsubbsat_dv
+; CHECK: v[[#]]:[[#]].b = vsub(v[[#]]:[[#]].b,v[[#]]:[[#]].b):sat
+define dso_local <256 x i8> @vsubbsat_dv(<256 x i8> %x, <256 x i8> %y) {
+entry:
+  %0 = tail call <256 x i8> @llvm.ssub.sat.v256i8(<256 x i8> %x, <256 x i8> %y)
+  ret <256 x i8> %0
+}
+
+; CHECK-LABEL: vsubhsat_dv
+; CHECK: v[[#]]:[[#]].h = vsub(v[[#]]:[[#]].h,v[[#]]:[[#]].h):sat
+define dso_local <128 x i16> @vsubhsat_dv(<128 x i16> %x, <128 x i16> %y) {
+entry:
+  %0 = tail call <128 x i16> @llvm.ssub.sat.v128i16(<128 x i16> %x, <128 x i16> %y)
+  ret <128 x i16> %0
+}
+
+; CHECK-LABEL: vsubwsat_dv
+; CHECK: v[[#]]:[[#]].w = vsub(v[[#]]:[[#]].w,v[[#]]:[[#]].w):sat
+define dso_local <64 x i32> @vsubwsat_dv(<64 x i32> %x, <64 x i32> %y) {
+entry:
+  %0 = tail call <64 x i32> @llvm.ssub.sat.v64i32(<64 x i32> %x, <64 x i32> %y)
+  ret <64 x i32> %0
+}