Index: cfe/trunk/lib/CodeGen/CGExprScalar.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/CGExprScalar.cpp
+++ cfe/trunk/lib/CodeGen/CGExprScalar.cpp
@@ -740,7 +740,7 @@
   }
 
   // Helper functions for fixed point binary operations.
-  Value *EmitFixedPointAdd(const BinOpInfo &Ops);
+  Value *EmitFixedPointBinOp(const BinOpInfo &Ops);
 
   BinOpInfo EmitBinOps(const BinaryOperator *E);
   LValue EmitCompoundAssignLValue(const CompoundAssignOperator *E,
@@ -3360,19 +3360,20 @@
   }
 
   if (op.isFixedPointBinOp())
-    return EmitFixedPointAdd(op);
+    return EmitFixedPointBinOp(op);
 
   return Builder.CreateAdd(op.LHS, op.RHS, "add");
 }
 
 /// The resulting value must be calculated with exact precision, so the operands
 /// may not be the same type.
-Value *ScalarExprEmitter::EmitFixedPointAdd(const BinOpInfo &op) {
+Value *ScalarExprEmitter::EmitFixedPointBinOp(const BinOpInfo &op) {
   using llvm::APSInt;
   using llvm::ConstantInt;
 
   const auto *BinOp = cast<BinaryOperator>(op.E);
-  assert(BinOp->getOpcode() == BO_Add && "Expected operation to be addition");
+  assert((BinOp->getOpcode() == BO_Add || BinOp->getOpcode() == BO_Sub) &&
+         "Expected operation to be addition or subtraction");
 
   // The result is a fixed point type and at least one of the operands is fixed
   // point while the other is either fixed point or an int. This resulting type
@@ -3397,13 +3398,62 @@
 
   // Perform the actual addition.
   Value *Result;
-  if (ResultFixedSema.isSaturated()) {
-    llvm::Intrinsic::ID IID = ResultFixedSema.isSigned()
-                                  ? llvm::Intrinsic::sadd_sat
-                                  : llvm::Intrinsic::uadd_sat;
-    Result = Builder.CreateBinaryIntrinsic(IID, FullLHS, FullRHS);
-  } else {
-    Result = Builder.CreateAdd(FullLHS, FullRHS);
+  switch (BinOp->getOpcode()) {
+  case BO_Add: {
+    if (ResultFixedSema.isSaturated()) {
+      llvm::Intrinsic::ID IID = ResultFixedSema.isSigned()
+                                    ? llvm::Intrinsic::sadd_sat
+                                    : llvm::Intrinsic::uadd_sat;
+      Result = Builder.CreateBinaryIntrinsic(IID, FullLHS, FullRHS);
+    } else {
+      Result = Builder.CreateAdd(FullLHS, FullRHS);
+    }
+    break;
+  }
+  case BO_Sub: {
+    if (ResultFixedSema.isSaturated()) {
+      llvm::Intrinsic::ID IID = ResultFixedSema.isSigned()
+                                    ? llvm::Intrinsic::ssub_sat
+                                    : llvm::Intrinsic::usub_sat;
+      Result = Builder.CreateBinaryIntrinsic(IID, FullLHS, FullRHS);
+    } else {
+      Result = Builder.CreateSub(FullLHS, FullRHS);
+    }
+    break;
+  }
+  case BO_Mul:
+  case BO_Div:
+  case BO_Shl:
+  case BO_Shr:
+  case BO_Cmp:
+  case BO_LT:
+  case BO_GT:
+  case BO_LE:
+  case BO_GE:
+  case BO_EQ:
+  case BO_NE:
+  case BO_LAnd:
+  case BO_LOr:
+  case BO_MulAssign:
+  case BO_DivAssign:
+  case BO_AddAssign:
+  case BO_SubAssign:
+  case BO_ShlAssign:
+  case BO_ShrAssign:
+    llvm_unreachable("Found unimplemented fixed point binary operation");
+  case BO_PtrMemD:
+  case BO_PtrMemI:
+  case BO_Rem:
+  case BO_Xor:
+  case BO_And:
+  case BO_Or:
+  case BO_Assign:
+  case BO_RemAssign:
+  case BO_AndAssign:
+  case BO_XorAssign:
+  case BO_OrAssign:
+  case BO_Comma:
+    llvm_unreachable("Found unsupported binary operation for fixed point types.");
   }
 
   // Convert to the result type.
@@ -3442,6 +3492,9 @@
       return propagateFMFlags(V, op);
     }
 
+    if (op.isFixedPointBinOp())
+      return EmitFixedPointBinOp(op);
+
     return Builder.CreateSub(op.LHS, op.RHS, "sub");
   }
 
Index: cfe/trunk/test/Frontend/fixed_point_sub.c
===================================================================
--- cfe/trunk/test/Frontend/fixed_point_sub.c
+++ cfe/trunk/test/Frontend/fixed_point_sub.c
@@ -0,0 +1,390 @@
+// RUN: %clang_cc1 -ffixed-point -S -emit-llvm %s -o - | FileCheck %s --check-prefixes=CHECK,SIGNED
+// RUN: %clang_cc1 -ffixed-point -fpadding-on-unsigned-fixed-point -S -emit-llvm %s -o - | FileCheck %s --check-prefixes=CHECK,UNSIGNED
+
+void SignedSubtraction() {
+  // CHECK-LABEL: SignedSubtraction
+  short _Accum sa;
+  _Accum a, b, c, d;
+  long _Accum la;
+  unsigned short _Accum usa;
+  unsigned _Accum ua;
+  unsigned long _Accum ula;
+
+  short _Fract sf;
+  _Fract f;
+  long _Fract lf;
+  unsigned short _Fract usf;
+  unsigned _Fract uf;
+  unsigned long _Fract ulf;
+
+  // Same type
+  // CHECK:      [[SA:%[0-9]+]] = load i16, i16* %sa, align 2
+  // CHECK-NEXT: [[SA2:%[0-9]+]] = load i16, i16* %sa, align 2
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = sub i16 [[SA]], [[SA2]]
+  // CHECK-NEXT: store i16 [[SUM]], i16* %sa, align 2
+  sa = sa - sa;
+
+  // To larger scale and larger width
+  // CHECK:      [[SA:%[0-9]+]] = load i16, i16* %sa, align 2
+  // CHECK-NEXT: [[A:%[0-9]+]] = load i32, i32* %a, align 4
+  // CHECK-NEXT: [[EXT_SA:%[a-z0-9]+]] = sext i16 [[SA]] to i32
+  // CHECK-NEXT: [[SA:%[a-z0-9]+]] = shl i32 [[EXT_SA]], 8
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = sub i32 [[SA]], [[A]]
+  // CHECK-NEXT: store i32 [[SUM]], i32* %a, align 4
+  a = sa - a;
+
+  // To same scale and smaller width
+  // CHECK:      [[SA:%[0-9]+]] = load i16, i16* %sa, align 2
+  // CHECK-NEXT: [[SF:%[0-9]+]] = load i8, i8* %sf, align 1
+  // CHECK-NEXT: [[EXT_SF:%[a-z0-9]+]] = sext i8 [[SF]] to i16
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = sub i16 [[SA]], [[EXT_SF]]
+  // CHECK-NEXT: store i16 [[SUM]], i16* %sa, align 2
+  sa = sa - sf;
+
+  // To smaller scale and same width.
+  // CHECK:      [[SA:%[0-9]+]] = load i16, i16* %sa, align 2
+  // CHECK-NEXT: [[F:%[0-9]+]] = load i16, i16* %f, align 2
+  // CHECK-NEXT: [[EXT_SA:%[a-z0-9]+]] = sext i16 [[SA]] to i24
+  // CHECK-NEXT: [[SA:%[a-z0-9]+]] = shl i24 [[EXT_SA]], 8
+  // CHECK-NEXT: [[EXT_F:%[a-z0-9]+]] = sext i16 [[F]] to i24
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = sub i24 [[SA]], [[EXT_F]]
+  // CHECK-NEXT: [[RES:%[a-z0-9]+]] = ashr i24 [[SUM]], 8
+  // CHECK-NEXT: [[TRUNC_RES:%[a-z0-9]+]] = trunc i24 [[RES]] to i16
+  // CHECK-NEXT: store i16 [[TRUNC_RES]], i16* %sa, align 2
+  sa = sa - f;
+
+  // To smaller scale and smaller width
+  // CHECK:      [[A:%[0-9]+]] = load i32, i32* %a, align 4
+  // CHECK-NEXT: [[SF:%[0-9]+]] = load i8, i8* %sf, align 1
+  // CHECK-NEXT: [[EXT_SF:%[a-z0-9]+]] = sext i8 [[SF]] to i32
+  // CHECK-NEXT: [[SF:%[a-z0-9]+]] = shl i32 [[EXT_SF]], 8
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = sub i32 [[A]], [[SF]]
+  // CHECK-NEXT: store i32 [[SUM]], i32* %a, align 4
+  a = a - sf;
+
+  // To larger scale and same width
+  // CHECK:      [[A:%[0-9]+]] = load i32, i32* %a, align 4
+  // CHECK-NEXT: [[LF:%[0-9]+]] = load i32, i32* %lf, align 4
+  // CHECK-NEXT: [[EXT_A:%[a-z0-9]+]] = sext i32 [[A]] to i48
+  // CHECK-NEXT: [[A:%[a-z0-9]+]] = shl i48 [[EXT_A]], 16
+  // CHECK-NEXT: [[EXT_LF:%[a-z0-9]+]] = sext i32 [[LF]] to i48
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = sub i48 [[A]], [[EXT_LF]]
+  // CHECK-NEXT: [[RES:%[a-z0-9]+]] = ashr i48 [[SUM]], 16
+  // CHECK-NEXT: [[TRUNC_RES:%[a-z0-9]+]] = trunc i48 [[RES]] to i32
+  // CHECK-NEXT: store i32 [[TRUNC_RES]], i32* %a, align 4
+  a = a - lf;
+
+  // With corresponding unsigned type
+  // CHECK:      [[SA:%[0-9]+]] = load i16, i16* %sa, align 2
+  // CHECK-NEXT: [[USA:%[0-9]+]] = load i16, i16* %usa, align 2
+  // SIGNED-NEXT: [[SA_EXT:%[a-z0-9]+]] = sext i16 [[SA]] to i17
+  // SIGNED-NEXT: [[SA:%[a-z0-9]+]] = shl i17 [[SA_EXT]], 1
+  // SIGNED-NEXT: [[USA_EXT:%[a-z0-9]+]] = zext i16 [[USA]] to i17
+  // SIGNED-NEXT: [[SUM:%[0-9]+]] = sub i17 [[SA]], [[USA_EXT]]
+  // SIGNED-NEXT: [[RESULT:%[a-z0-9]+]] = ashr i17 [[SUM]], 1
+  // SIGNED-NEXT: [[SUM:%[a-z0-9]+]] = trunc i17 [[RESULT]] to i16
+  // UNSIGNED-NEXT: [[SUM:%[0-9]+]] = sub i16 [[SA]], [[USA]]
+  // CHECK-NEXT: store i16 [[SUM]], i16* %sa, align 2
+  sa = sa - usa;
+
+  // With unsigned of larger scale
+  // CHECK:      [[SA:%[0-9]+]] = load i16, i16* %sa, align 2
+  // CHECK-NEXT: [[USA:%[0-9]+]] = load i32, i32* %ua, align 4
+  // SIGNED-NEXT: [[SA_EXT:%[a-z0-9]+]] = sext i16 [[SA]] to i33
+  // SIGNED-NEXT: [[SA:%[a-z0-9]+]] = shl i33 [[SA_EXT]], 9
+  // SIGNED-NEXT: [[USA_EXT:%[a-z0-9]+]] = zext i32 [[USA]] to i33
+  // SIGNED-NEXT: [[SUM:%[0-9]+]] = sub i33 [[SA]], [[USA_EXT]]
+  // SIGNED-NEXT: [[RESULT:%[a-z0-9]+]] = ashr i33 [[SUM]], 1
+  // SIGNED-NEXT: [[SUM:%[a-z0-9]+]] = trunc i33 [[RESULT]] to i32
+  // UNSIGNED-NEXT: [[EXT_SA:%[a-z0-9]+]] = sext i16 [[SA]] to i32
+  // UNSIGNED-NEXT: [[SA:%[a-z0-9]+]] = shl i32 [[EXT_SA]], 8
+  // UNSIGNED-NEXT: [[SUM:%[0-9]+]] = sub i32 [[SA]], [[USA]]
+  // CHECK-NEXT: store i32 [[SUM]], i32* %a, align 4
+  a = sa - ua;
+
+  // With unsigned of smaller width
+  // CHECK:      [[SA:%[0-9]+]] = load i16, i16* %sa, align 2
+  // CHECK-NEXT: [[USF:%[0-9]+]] = load i8, i8* %usf, align 1
+  // SIGNED-NEXT: [[SA_EXT:%[a-z0-9]+]] = sext i16 [[SA]] to i17
+  // SIGNED-NEXT: [[SA:%[a-z0-9]+]] = shl i17 [[SA_EXT]], 1
+  // SIGNED-NEXT: [[USF_EXT:%[a-z0-9]+]] = zext i8 [[USF]] to i17
+  // SIGNED-NEXT: [[SUM:%[0-9]+]] = sub i17 [[SA]], [[USF_EXT]]
+  // SIGNED-NEXT: [[RESULT:%[a-z0-9]+]] = ashr i17 [[SUM]], 1
+  // SIGNED-NEXT: [[SUM:%[a-z0-9]+]] = trunc i17 [[RESULT]] to i16
+  // UNSIGNED-NEXT: [[EXT_USF:%[a-z0-9]+]] = zext i8 [[USF]] to i16
+  // UNSIGNED-NEXT: [[SUM:%[0-9]+]] = sub i16 [[SA]], [[EXT_USF]]
+  // CHECK-NEXT: store i16 [[SUM]], i16* %sa, align 2
+  sa = sa - usf;
+
+  // With unsigned of larger width and smaller scale
+  // CHECK:      [[SA:%[0-9]+]] = load i16, i16* %sa, align 2
+  // CHECK-NEXT: [[ULF:%[0-9]+]] = load i32, i32* %ulf, align 4
+  // SIGNED-NEXT: [[SA_EXT:%[a-z0-9]+]] = sext i16 [[SA]] to i41
+  // SIGNED-NEXT: [[SA:%[a-z0-9]+]] = shl i41 [[SA_EXT]], 25
+  // SIGNED-NEXT: [[ULF_EXT:%[a-z0-9]+]] = zext i32 [[ULF]] to i41
+  // SIGNED-NEXT: [[SUM:%[0-9]+]] = sub i41 [[SA]], [[ULF_EXT]]
+  // SIGNED-NEXT: [[RESULT:%[a-z0-9]+]] = ashr i41 [[SUM]], 25
+  // SIGNED-NEXT: [[RES_TRUNC:%[a-z0-9]+]] = trunc i41 [[RESULT]] to i16
+  // UNSIGNED-NEXT: [[EXT_SA:%[a-z0-9]+]] = sext i16 [[SA]] to i40
+  // UNSIGNED-NEXT: [[SA:%[a-z0-9]+]] = shl i40 [[EXT_SA]], 24
+  // UNSIGNED-NEXT: [[EXT_ULF:%[a-z0-9]+]] = zext i32 [[ULF]] to i40
+  // UNSIGNED-NEXT: [[SUM:%[0-9]+]] = sub i40 [[SA]], [[EXT_ULF]]
+  // UNSIGNED-NEXT: [[RES:%[a-z0-9]+]] = ashr i40 [[SUM]], 24
+  // UNSIGNED-NEXT: [[RES_TRUNC:%[a-z0-9]+]] = trunc i40 [[RES]] to i16
+  // CHECK-NEXT: store i16 [[RES_TRUNC]], i16* %sa, align 2
+  sa = sa - ulf;
+
+  // Chained additions of the same signed type should result in the same
+  // semantics width.
+  // CHECK:      [[A:%[0-9]+]] = load i32, i32* %a, align 4
+  // CHECK-NEXT: [[B:%[0-9]+]] = load i32, i32* %b, align 4
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = sub i32 [[A]], [[B]]
+  // CHECK-NEXT: [[C:%[0-9]+]] = load i32, i32* %c, align 4
+  // CHECK-NEXT: [[SUM2:%[0-9]+]] = sub i32 [[SUM]], [[C]]
+  // CHECK-NEXT: [[D:%[0-9]+]] = load i32, i32* %d, align 4
+  // CHECK-NEXT: [[SUM3:%[0-9]+]] = sub i32 [[SUM2]], [[D]]
+  // CHECK-NEXT: store i32 [[SUM3]], i32* %a, align 4
+  a = a - b - c - d;
+}
+
+void UnsignedSubtraction() {
+  // CHECK-LABEL: UnsignedSubtraction
+  unsigned short _Accum usa;
+  unsigned _Accum ua;
+  unsigned long _Accum ula;
+
+  unsigned short _Fract usf;
+  unsigned _Fract uf;
+  unsigned long _Fract ulf;
+
+  // CHECK:      [[USA:%[0-9]+]] = load i16, i16* %usa, align 2
+  // CHECK-NEXT: [[USA2:%[0-9]+]] = load i16, i16* %usa, align 2
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = sub i16 [[USA]], [[USA2]]
+  // CHECK-NEXT: store i16 [[SUM]], i16* %usa, align 2
+  usa = usa - usa;
+
+  // CHECK:      [[USA:%[0-9]+]] = load i16, i16* %usa, align 2
+  // CHECK-NEXT: [[UA:%[0-9]+]] = load i32, i32* %ua, align 4
+  // CHECK-NEXT: [[EXT_USA:%[a-z0-9]+]] = zext i16 [[USA]] to i32
+  // CHECK-NEXT: [[USA:%[a-z0-9]+]] = shl i32 [[EXT_USA]], 8
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = sub i32 [[USA]], [[UA]]
+  // CHECK-NEXT: store i32 [[SUM]], i32* %ua, align 4
+  ua = usa - ua;
+
+  // CHECK:      [[USA:%[0-9]+]] = load i16, i16* %usa, align 2
+  // CHECK-NEXT: [[USF:%[0-9]+]] = load i8, i8* %usf, align 1
+  // CHECK-NEXT: [[EXT_USF:%[a-z0-9]+]] = zext i8 [[USF]] to i16
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = sub i16 [[USA]], [[EXT_USF]]
+  // CHECK-NEXT: store i16 [[SUM]], i16* %usa, align 2
+  usa = usa - usf;
+
+  // CHECK:      [[USA:%[0-9]+]] = load i16, i16* %usa, align 2
+  // CHECK-NEXT: [[UF:%[0-9]+]] = load i16, i16* %uf, align 2
+  // CHECK-NEXT: [[USA_EXT:%[a-z0-9]+]] = zext i16 [[USA]] to i24
+  // CHECK-NEXT: [[USA:%[a-z0-9]+]] = shl i24 [[USA_EXT]], 8
+  // CHECK-NEXT: [[UF_EXT:%[a-z0-9]+]] = zext i16 [[UF]] to i24
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = sub i24 [[USA]], [[UF_EXT]]
+  // CHECK-NEXT: [[RES:%[a-z0-9]+]] = lshr i24 [[SUM]], 8
+  // CHECK-NEXT: [[RES_TRUNC:%[a-z0-9]+]] = trunc i24 [[RES]] to i16
+  // CHECK-NEXT: store i16 [[RES_TRUNC]], i16* %usa, align 2
+  usa = usa - uf;
+}
+
+void IntSubtraction() {
+  // CHECK-LABEL: IntSubtraction
+  short _Accum sa;
+  _Accum a;
+  unsigned short _Accum usa;
+  _Sat short _Accum sa_sat;
+  int i;
+  unsigned int ui;
+  long _Fract lf;
+  _Bool b;
+
+  // CHECK:      [[SA:%[0-9]+]] = load i16, i16* %sa, align 2
+  // CHECK-NEXT: [[I:%[0-9]+]] = load i32, i32* %i, align 4
+  // CHECK-NEXT: [[SA_EXT:%[a-z0-9]+]] = sext i16 [[SA]] to i39
+  // CHECK-NEXT: [[I_EXT:%[a-z0-9]+]] = sext i32 [[I]] to i39
+  // CHECK-NEXT: [[I:%[a-z0-9]+]] = shl i39 [[I_EXT]], 7
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = sub i39 [[SA_EXT]], [[I]]
+  // CHECK-NEXT: [[RES:%[a-z0-9]+]] = trunc i39 [[SUM]] to i16
+  // CHECK-NEXT: store i16 [[RES]], i16* %sa, align 2
+  sa = sa - i;
+
+  // CHECK:      [[SA:%[0-9]+]] = load i16, i16* %sa, align 2
+  // CHECK-NEXT: [[UI:%[0-9]+]] = load i32, i32* %ui, align 4
+  // CHECK-NEXT: [[SA_EXT:%[a-z0-9]+]] = sext i16 [[SA]] to i40
+  // CHECK-NEXT: [[UI_EXT:%[a-z0-9]+]] = zext i32 [[UI]] to i40
+  // CHECK-NEXT: [[UI:%[a-z0-9]+]] = shl i40 [[UI_EXT]], 7
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = sub i40 [[SA_EXT]], [[UI]]
+  // CHECK-NEXT: [[RES:%[a-z0-9]+]] = trunc i40 [[SUM]] to i16
+  // CHECK-NEXT: store i16 [[RES]], i16* %sa, align 2
+  sa = sa - ui;
+
+  // CHECK:      [[USA:%[0-9]+]] = load i16, i16* %usa, align 2
+  // CHECK-NEXT: [[I:%[0-9]+]] = load i32, i32* %i, align 4
+  // SIGNED-NEXT: [[USA_EXT:%[a-z0-9]+]] = zext i16 [[USA]] to i40
+  // SIGNED-NEXT: [[I_EXT:%[a-z0-9]+]] = sext i32 [[I]] to i40
+  // SIGNED-NEXT: [[I:%[a-z0-9]+]] = shl i40 [[I_EXT]], 8
+  // SIGNED-NEXT: [[SUM:%[0-9]+]] = sub i40 [[USA_EXT]], [[I]]
+  // SIGNED-NEXT: [[RES:%[a-z0-9]+]] = trunc i40 [[SUM]] to i16
+  // UNSIGNED-NEXT: [[USA_EXT:%[a-z0-9]+]] = zext i16 [[USA]] to i39
+  // UNSIGNED-NEXT: [[I_EXT:%[a-z0-9]+]] = sext i32 [[I]] to i39
+  // UNSIGNED-NEXT: [[I:%[a-z0-9]+]] = shl i39 [[I_EXT]], 7
+  // UNSIGNED-NEXT: [[SUM:%[0-9]+]] = sub i39 [[USA_EXT]], [[I]]
+  // UNSIGNED-NEXT: [[RES:%[a-z0-9]+]] = trunc i39 [[SUM]] to i16
+  // CHECK-NEXT: store i16 [[RES]], i16* %usa, align 2
+  usa = usa - i;
+
+  // CHECK:      [[USA:%[0-9]+]] = load i16, i16* %usa, align 2
+  // CHECK-NEXT: [[I:%[0-9]+]] = load i32, i32* %ui, align 4
+  // SIGNED-NEXT: [[USA_EXT:%[a-z0-9]+]] = zext i16 [[USA]] to i40
+  // SIGNED-NEXT: [[I_EXT:%[a-z0-9]+]] = zext i32 [[I]] to i40
+  // SIGNED-NEXT: [[I:%[a-z0-9]+]] = shl i40 [[I_EXT]], 8
+  // SIGNED-NEXT: [[SUM:%[0-9]+]] = sub i40 [[USA_EXT]], [[I]]
+  // SIGNED-NEXT: [[RES:%[a-z0-9]+]] = trunc i40 [[SUM]] to i16
+  // UNSIGNED-NEXT: [[USA_EXT:%[a-z0-9]+]] = zext i16 [[USA]] to i39
+  // UNSIGNED-NEXT: [[I_EXT:%[a-z0-9]+]] = zext i32 [[I]] to i39
+  // UNSIGNED-NEXT: [[I:%[a-z0-9]+]] = shl i39 [[I_EXT]], 7
+  // UNSIGNED-NEXT: [[SUM:%[0-9]+]] = sub i39 [[USA_EXT]], [[I]]
+  // UNSIGNED-NEXT: [[RES:%[a-z0-9]+]] = trunc i39 [[SUM]] to i16
+  // CHECK-NEXT: store i16 [[RES]], i16* %usa, align 2
+  usa = usa - ui;
+
+  // CHECK:      [[LF:%[0-9]+]] = load i32, i32* %lf, align 4
+  // CHECK-NEXT: [[UI:%[0-9]+]] = load i32, i32* %ui, align 4
+  // CHECK-NEXT: [[LF_EXT:%[a-z0-9]+]] = sext i32 [[LF]] to i64
+  // CHECK-NEXT: [[UI_EXT:%[a-z0-9]+]] = zext i32 [[UI]] to i64
+  // CHECK-NEXT: [[UI:%[a-z0-9]+]] = shl i64 [[UI_EXT]], 31
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = sub i64 [[LF_EXT]], [[UI]]
+  // CHECK-NEXT: [[RES:%[a-z0-9]+]] = trunc i64 [[SUM]] to i32
+  // CHECK-NEXT: store i32 [[RES]], i32* %lf, align 4
+  lf = lf - ui;
+
+  // CHECK:      [[ACCUM:%[0-9]+]] = load i32, i32* %a, align 4
+  // CHECK-NEXT: [[BOOL:%[0-9]+]] = load i8, i8* %b, align 1
+  // CHECK-NEXT: [[AS_BOOL:%[a-z0-9]+]] = trunc i8 [[BOOL]] to i1
+  // CHECK-NEXT: [[BOOL_EXT:%[a-z0-9]+]] = zext i1 [[AS_BOOL]] to i32
+  // CHECK-NEXT: [[ACCUM_EXT:%[a-z0-9]+]] = sext i32 [[ACCUM]] to i47
+  // CHECK-NEXT: [[BOOL:%[a-z0-9]+]] = sext i32 [[BOOL_EXT]] to i47
+  // CHECK-NEXT: [[BOOL_EXT:%[a-z0-9]+]] = shl i47 [[BOOL]], 15
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = sub i47 [[ACCUM_EXT]], [[BOOL_EXT]]
+  // CHECK-NEXT: [[RESULT:%[a-z0-9]+]] = trunc i47 [[SUM]] to i32
+  // CHECK-NEXT: store i32 [[RESULT]], i32* %a, align 4
+  a = a - b;
+}
+
+void SaturatedSubtraction() {
+  // CHECK-LABEL: SaturatedSubtraction
+  short _Accum sa;
+  _Accum a;
+  long _Accum la;
+  unsigned short _Accum usa;
+  unsigned _Accum ua;
+  unsigned long _Accum ula;
+
+  _Sat short _Accum sa_sat;
+  _Sat _Accum a_sat;
+  _Sat long _Accum la_sat;
+  _Sat unsigned short _Accum usa_sat;
+  _Sat unsigned _Accum ua_sat;
+  _Sat unsigned long _Accum ula_sat;
+  _Sat unsigned _Fract uf_sat;
+
+  int i;
+  unsigned int ui;
+
+  // CHECK:      [[SA:%[0-9]+]] = load i16, i16* %sa, align 2
+  // CHECK-NEXT: [[SA_SAT:%[0-9]+]] = load i16, i16* %sa_sat, align 2
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = call i16 @llvm.ssub.sat.i16(i16 [[SA]], i16
+  // [[SA_SAT]])
+  // CHECK-NEXT: store i16 [[SUM]], i16* %sa_sat, align 2
+  sa_sat = sa - sa_sat;
+
+  // CHECK:      [[USA:%[0-9]+]] = load i16, i16* %usa, align 2
+  // CHECK-NEXT: [[USA_SAT:%[0-9]+]] = load i16, i16* %usa_sat, align 2
+  // SIGNED-NEXT: [[SUM:%[0-9]+]] = call i16 @llvm.usub.sat.i16(i16 [[USA]], i16 [[USA_SAT]])
+  // SIGNED-NEXT: store i16 [[SUM]], i16* %usa_sat, align 2
+  // UNSIGNED-NEXT: [[USA_TRUNC:%[a-z0-9]+]] = trunc i16 [[USA]] to i15
+  // UNSIGNED-NEXT: [[USA_SAT_TRUNC:%[a-z0-9]+]] = trunc i16 [[USA_SAT]] to i15
+  // UNSIGNED-NEXT: [[SUM:%[0-9]+]] = call i15 @llvm.usub.sat.i15(i15 [[USA_TRUNC]], i15 [[USA_SAT_TRUNC]])
+  // UNSIGNED-NEXT: [[SUM_EXT:%[a-z0-9]+]] = zext i15 [[SUM]] to i16
+  // UNSIGNED-NEXT: store i16 [[SUM_EXT]], i16* %usa_sat, align 2
+  usa_sat = usa - usa_sat;
+
+  // CHECK:      [[UA:%[0-9]+]] = load i32, i32* %ua, align 4
+  // CHECK-NEXT: [[USA:%[0-9]+]] = load i16, i16* %usa_sat, align 2
+  // SIGNED-NEXT: [[USA_EXT:%[a-z0-9]+]] = zext i16 [[USA]] to i32
+  // SIGNED-NEXT: [[USA:%[a-z0-9]+]] = shl i32 [[USA_EXT]], 8
+  // SIGNED-NEXT: [[SUM:%[0-9]+]] = call i32 @llvm.usub.sat.i32(i32 [[UA]], i32 [[USA]])
+  // SIGNED-NEXT: store i32 [[SUM]], i32* %ua_sat, align 4
+  // UNSIGNED-NEXT: [[UA_TRUNC:%[a-z0-9]+]] = trunc i32 [[UA]] to i31
+  // UNSIGNED-NEXT: [[USA_EXT:%[a-z0-9]+]] = zext i16 [[USA]] to i31
+  // UNSIGNED-NEXT: [[USA:%[a-z0-9]+]] = shl i31 [[USA_EXT]], 8
+  // UNSIGNED-NEXT: [[SUM:%[0-9]+]] = call i31 @llvm.usub.sat.i31(i31 [[UA_TRUNC]], i31 [[USA]])
+  // UNSIGNED-NEXT: [[SUM_EXT:%[a-z0-9]+]] = zext i31 [[SUM]] to i32
+  // UNSIGNED-NEXT: store i32 [[SUM_EXT]], i32* %ua_sat, align 4
+  ua_sat = ua - usa_sat;
+
+  // CHECK:      [[SA_SAT:%[0-9]+]] = load i16, i16* %sa_sat, align 2
+  // CHECK-NEXT: [[I:%[0-9]+]] = load i32, i32* %i, align 4
+  // CHECK-NEXT: [[SA_SAT_EXT:%[a-z0-9]+]] = sext i16 [[SA_SAT]] to i39
+  // CHECK-NEXT: [[I_EXT:%[a-z0-9]+]] = sext i32 [[I]] to i39
+  // CHECK-NEXT: [[I:%[a-z0-9]+]] = shl i39 [[I_EXT]], 7
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = call i39 @llvm.ssub.sat.i39(i39 [[SA_SAT_EXT]], i39 [[I]])
+  // CHECK-NEXT: [[USE_MAX:%[0-9]+]] = icmp sgt i39 [[SUM]], 32767
+  // CHECK-NEXT: [[RES:%[a-z0-9]+]] = select i1 [[USE_MAX]], i39 32767, i39 [[SUM]]
+  // CHECK-NEXT: [[USE_MIN:%[0-9]+]] = icmp slt i39 [[RES]], -32768
+  // CHECK-NEXT: [[RES2:%[a-z0-9]+]] = select i1 [[USE_MIN]], i39 -32768, i39 [[RES]]
+  // CHECK-NEXT: [[RES3:%[a-z0-9]+]] = trunc i39 [[RES2]] to i16
+  // CHECK-NEXT: store i16 [[RES3]], i16* %sa_sat, align 2
+  sa_sat = sa_sat - i;
+
+  // CHECK:      [[SA_SAT:%[0-9]+]] = load i16, i16* %sa_sat, align 2
+  // CHECK-NEXT: [[I:%[0-9]+]] = load i32, i32* %ui, align 4
+  // CHECK-NEXT: [[SA_SAT_EXT:%[a-z0-9]+]] = sext i16 [[SA_SAT]] to i40
+  // CHECK-NEXT: [[I_EXT:%[a-z0-9]+]] = zext i32 [[I]] to i40
+  // CHECK-NEXT: [[I:%[a-z0-9]+]] = shl i40 [[I_EXT]], 7
+  // CHECK-NEXT: [[SUM:%[0-9]+]] = call i40 @llvm.ssub.sat.i40(i40 [[SA_SAT_EXT]], i40 [[I]])
+  // CHECK-NEXT: [[USE_MAX:%[0-9]+]] = icmp sgt i40 [[SUM]], 32767
+  // CHECK-NEXT: [[RES:%[a-z0-9]+]] = select i1 [[USE_MAX]], i40 32767, i40 [[SUM]]
+  // CHECK-NEXT: [[USE_MIN:%[0-9]+]] = icmp slt i40 [[RES]], -32768
+  // CHECK-NEXT: [[RES2:%[a-z0-9]+]] = select i1 [[USE_MIN]], i40 -32768, i40 [[RES]]
+  // CHECK-NEXT: [[RES3:%[a-z0-9]+]] = trunc i40 [[RES2]] to i16
+  // CHECK-NEXT: store i16 [[RES3]], i16* %sa_sat, align 2
+  sa_sat = sa_sat - ui;
+
+  // CHECK:      [[UF_SAT:%[0-9]+]] = load i16, i16* %uf_sat, align 2
+  // CHECK-NEXT: [[UF_SAT2:%[0-9]+]] = load i16, i16* %uf_sat, align 2
+  // SIGNED-NEXT: [[SUM:%[0-9]+]] = call i16 @llvm.usub.sat.i16(i16 [[UF_SAT]], i16 [[UF_SAT2]])
+  // SIGNED-NEXT: store i16 [[SUM]], i16* %uf_sat, align 2
+  // UNSIGNED-NEXT: [[UF_SAT_TRUNC:%[a-z0-9]+]] = trunc i16 [[UF_SAT]] to i15
+  // UNSIGNED-NEXT: [[UF_SAT_TRUNC2:%[a-z0-9]+]] = trunc i16 [[UF_SAT2]] to i15
+  // UNSIGNED-NEXT: [[SUM:%[0-9]+]] = call i15 @llvm.usub.sat.i15(i15 [[UF_SAT_TRUNC]], i15 [[UF_SAT_TRUNC2]])
+  // UNSIGNED-NEXT: [[SUM_EXT:%[a-z0-9]+]] = zext i15 [[SUM]] to i16
+  // UNSIGNED-NEXT: store i16 [[SUM_EXT]], i16* %uf_sat, align 2
+  uf_sat = uf_sat - uf_sat;
+
+  // CHECK:      [[USA_SAT:%[0-9]+]] = load i16, i16* %usa_sat, align 2
+  // CHECK-NEXT: [[I:%[0-9]+]] = load i32, i32* %i, align 4
+  // SIGNED-NEXT: [[USA_SAT_RESIZE:%[a-z0-9]+]] = zext i16 [[USA_SAT]] to i40
+  // SIGNED-NEXT: [[I_RESIZE:%[a-z0-9]+]] = sext i32 [[I]] to i40
+  // SIGNED-NEXT: [[I_UPSCALE:%[a-z0-9]+]] = shl i40 [[I_RESIZE]], 8
+  // SIGNED-NEXT: [[SUM:%[0-9]+]] = call i40 @llvm.usub.sat.i40(i40 [[USA_SAT_RESIZE]], i40 [[I_UPSCALE]])
+  // SIGNED-NEXT: [[USE_MAX:%[0-9]+]] = icmp sgt i40 [[SUM]], 65535
+  // SIGNED-NEXT: [[RESULT:%[a-z0-9]+]] = select i1 [[USE_MAX]], i40 65535, i40 [[SUM]]
+  // SIGNED-NEXT: [[USE_MIN:%[0-9]+]] = icmp slt i40 [[RESULT]], 0
+  // SIGNED-NEXT: [[RESULT2:%[a-z0-9]+]] = select i1 [[USE_MIN]], i40 0, i40 [[RESULT]]
+  // SIGNED-NEXT: [[RESULT:%[a-z0-9]+]] = trunc i40 [[RESULT2]] to i16
+  // UNSIGNED-NEXT: [[USA_SAT_RESIZE:%[a-z0-9]+]] = zext i16 [[USA_SAT]] to i39
+  // UNSIGNED-NEXT: [[I_RESIZE:%[a-z0-9]+]] = sext i32 [[I]] to i39
+  // UNSIGNED-NEXT: [[I_UPSCALE:%[a-z0-9]+]] = shl i39 [[I_RESIZE]], 7
+  // UNSIGNED-NEXT: [[SUM:%[0-9]+]] = call i39 @llvm.usub.sat.i39(i39 [[USA_SAT_RESIZE]], i39 [[I_UPSCALE]])
+  // UNSIGNED-NEXT: [[USE_MAX:%[0-9]+]] = icmp sgt i39 [[SUM]], 32767
+  // UNSIGNED-NEXT: [[RESULT:%[a-z0-9]+]] = select i1 [[USE_MAX]], i39 32767, i39 [[SUM]]
+  // UNSIGNED-NEXT: [[USE_MIN:%[0-9]+]] = icmp slt i39 [[RESULT]], 0
+  // UNSIGNED-NEXT: [[RESULT2:%[a-z0-9]+]] = select i1 [[USE_MIN]], i39 0, i39 [[RESULT]]
+  // UNSIGNED-NEXT: [[RESULT:%[a-z0-9]+]] = trunc i39 [[RESULT2]] to i16
+  // CHECK-NEXT: store i16 [[RESULT]], i16* %usa_sat, align 2
+  usa_sat = usa_sat - i;
+}