[Clang] VectorExprEvaluator::VisitCallExpr / InterpretBuiltin - allow SSE41 phminposuw intrinsic to be used in constexp

clang/include/clang/Basic/BuiltinsX86.td

@@ -334,8 +334,8 @@ let Features = "sse4.1", Attributes = [NoThrow, Const, RequiredVectorWidth<128>]
   def dpps : X86Builtin<"_Vector<4, float>(_Vector<4, float>, _Vector<4, float>, _Constant char)">;
   def dppd : X86Builtin<"_Vector<2, double>(_Vector<2, double>, "
                         "_Vector<2,double>, _Constant char)">;
-  def mpsadbw128 : X86Builtin<"_Vector<16, char>(_Vector<16, char>, _Vector<16, char>, _Constant char)">;
-  def phminposuw128 : X86Builtin<"_Vector<8, short>(_Vector<8, short>)">;
+  def mpsadbw128 : X86Builtin<"_Vector<16, char>(_Vector<16, char>, "
+                              "_Vector<16, char>, _Constant char)">;
 }
 
 let Features = "sse4.1",
@@ -358,6 +358,7 @@ let Features = "sse4.1", Attributes = [NoThrow, Const, Constexpr, RequiredVector
 
   def pmuldq128 : X86Builtin<"_Vector<2, long long int>(_Vector<4, int>, _Vector<4, int>)">;
   def packusdw128 : X86Builtin<"_Vector<8, short>(_Vector<4, int>, _Vector<4, int>)">;
+  def phminposuw128 : X86Builtin<"_Vector<8, short>(_Vector<8, short>)">;
 
   def vec_ext_v16qi : X86Builtin<"char(_Vector<16, char>, _Constant int)">;
   def vec_set_v16qi : X86Builtin<"_Vector<16, char>(_Vector<16, char>, char, _Constant int)">;

clang/lib/AST/ByteCode/InterpBuiltin.cpp

@@ -3003,6 +3003,45 @@ static bool interp__builtin_x86_insert_subvector(InterpState &S, CodePtr OpPC,
   return true;
 }
 
+static bool interp__builtin_ia32_phminposuw(InterpState &S, CodePtr OpPC,
+                                            const CallExpr *Call) {
+  assert(Call->getNumArgs() == 1);
+
+  const Pointer &Source = S.Stk.pop<Pointer>();
+  const Pointer &Dest = S.Stk.peek<Pointer>();
+
+  unsigned SourceLen = Source.getNumElems();
+  QualType ElemQT = getElemType(Source);
+  OptPrimType ElemT = S.getContext().classify(ElemQT);
+  unsigned ElemBitWidth = S.getASTContext().getTypeSize(ElemQT);
+
+  bool DestUnsigned = Call->getCallReturnType(S.getASTContext())
+                          ->castAs<VectorType>()
+                          ->getElementType()
+                          ->isUnsignedIntegerOrEnumerationType();
+
+  INT_TYPE_SWITCH_NO_BOOL(*ElemT, {
+    APSInt MinIndex(ElemBitWidth, DestUnsigned);
+    APSInt MinVal = Source.elem<T>(0).toAPSInt();
+
+    for (unsigned I = 1; I != SourceLen; ++I) {
+      APSInt Val = Source.elem<T>(I).toAPSInt();
+      if (MinVal.ugt(Val)) {
+        MinVal = Val;
+        MinIndex = I;
+      }
+    }
+
+    Dest.elem<T>(0) = static_cast<T>(MinVal);
+    Dest.elem<T>(1) = static_cast<T>(MinIndex);
+    for (unsigned I = 2; I != SourceLen; ++I) {
+      Dest.elem<T>(I) = static_cast<T>(APSInt(ElemBitWidth, DestUnsigned));
+    }
+  });
+  Dest.initializeAllElements();
+  return true;
+}
+
 static bool interp__builtin_ia32_pternlog(InterpState &S, CodePtr OpPC,
                                           const CallExpr *Call, bool MaskZ) {
   assert(Call->getNumArgs() == 5);
@@ -4087,6 +4126,9 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const CallExpr *Call,
         S, OpPC, Call,
         [](const APSInt &LHS, const APSInt &RHS) { return LHS + RHS; });
 
+  case X86::BI__builtin_ia32_phminposuw128:
+    return interp__builtin_ia32_phminposuw(S, OpPC, Call);
+
   case X86::BI__builtin_ia32_pternlogd128_mask:
   case X86::BI__builtin_ia32_pternlogd256_mask:
   case X86::BI__builtin_ia32_pternlogd512_mask:

clang/lib/AST/ExprConstant.cpp

@@ -12353,6 +12353,40 @@ bool VectorExprEvaluator::VisitCallExpr(const CallExpr *E) {
     return Success(R, E);
   }
 
+  case X86::BI__builtin_ia32_phminposuw128: {
+    APValue Source;
+    if (!Evaluate(Source, Info, E->getArg(0)))
+      return false;
+    unsigned SourceLen = Source.getVectorLength();
+    const VectorType *VT = E->getArg(0)->getType()->castAs<VectorType>();
+    QualType ElemQT = VT->getElementType();
+    unsigned ElemBitWidth = Info.Ctx.getTypeSize(ElemQT);
+
+    APInt MinIndex(ElemBitWidth, 0);
+    APInt MinVal = Source.getVectorElt(0).getInt();
+    for (unsigned I = 1; I != SourceLen; ++I) {
+      APInt Val = Source.getVectorElt(I).getInt();
+      if (MinVal.ugt(Val)) {
+        MinVal = Val;
+        MinIndex = I;
+      }
+    }
+
+    bool ResultUnsigned = E->getCallReturnType(Info.Ctx)
+                              ->castAs<VectorType>()
+                              ->getElementType()
+                              ->isUnsignedIntegerOrEnumerationType();
+
+    SmallVector<APValue, 8> Result;
+    Result.reserve(SourceLen);
+    Result.emplace_back(APSInt(MinVal, ResultUnsigned));
+    Result.emplace_back(APSInt(MinIndex, ResultUnsigned));
+    for (unsigned I = 0; I != SourceLen - 2; ++I) {
+      Result.emplace_back(APSInt(APInt(ElemBitWidth, 0), ResultUnsigned));
+    }
+    return Success(APValue(Result.data(), Result.size()), E);
+  }
+
   case X86::BI__builtin_ia32_pternlogd128_mask:
   case X86::BI__builtin_ia32_pternlogd256_mask:
   case X86::BI__builtin_ia32_pternlogd512_mask:

clang/lib/Headers/smmintrin.h

@@ -1524,7 +1524,8 @@ _mm_packus_epi32(__m128i __V1, __m128i __V2) {
 /// \returns A 128-bit value where bits [15:0] contain the minimum value found
 ///    in parameter \a __V, bits [18:16] contain the index of the minimum value
 ///    and the remaining bits are set to 0.
-static __inline__ __m128i __DEFAULT_FN_ATTRS _mm_minpos_epu16(__m128i __V) {
+static __inline__ __m128i __DEFAULT_FN_ATTRS_CONSTEXPR
+_mm_minpos_epu16(__m128i __V) {
   return (__m128i)__builtin_ia32_phminposuw128((__v8hi)__V);
 }
 

clang/test/CodeGen/X86/sse41-builtins.c

@@ -376,6 +376,16 @@ __m128i test_mm_minpos_epu16(__m128i x) {
   // CHECK: call <8 x i16> @llvm.x86.sse41.phminposuw(<8 x i16> %{{.*}})
   return _mm_minpos_epu16(x);
 }
+TEST_CONSTEXPR(match_v8hu(_mm_minpos_epu16((__m128i)(__v8hu){0,0,0,0, 0,0,0,0}), 0,0,0,0, 0,0,0,0));
+TEST_CONSTEXPR(match_v8hu(_mm_minpos_epu16((__m128i)(__v8hu){1,0,0,0, 0,0,0,0}), 0,1,0,0, 0,0,0,0));
+TEST_CONSTEXPR(match_v8hu(_mm_minpos_epu16((__m128i)(__v8hu){65535,65535,65535,65535,65535,65535,65535,65535}), 65535,0,0,0, 0,0,0,0));
+TEST_CONSTEXPR(match_v8hu(_mm_minpos_epu16((__m128i)(__v8hu){9,8,7,6,5,4,3,2}), 2,7,0,0, 0,0,0,0));
+TEST_CONSTEXPR(match_v8hu(_mm_minpos_epu16((__m128i)(__v8hu){5,5,5,5,5,5,5,5}), 5,0,0,0, 0,0,0,0));
+TEST_CONSTEXPR(match_v8hu(_mm_minpos_epu16((__m128i)(__v8hu){5,7,9,4,10,4,11,12}), 4,3,0,0, 0,0,0,0));
+TEST_CONSTEXPR(match_v8hu(_mm_minpos_epu16((__m128i)(__v8hu){6,0,0,0,0,0,0,0}), 0,1,0,0, 0,0,0,0));
+TEST_CONSTEXPR(match_v8hu(_mm_minpos_epu16((__m128i)(__v8hu){1000,2000,3000,4000,5000,6000,7000,1}), 1,7,0,0, 0,0,0,0));
+TEST_CONSTEXPR(match_v8hu(_mm_minpos_epu16((__m128i)(__v8hu){1234,5678,42,9999,65535,0,4242,42}), 0,5,0,0, 0,0,0,0));
+TEST_CONSTEXPR(match_v8hu(_mm_minpos_epu16((__m128i)(__v8hu){400,500,12,600,12,700,800,900}), 12,2,0,0, 0,0,0,0));
 
 __m128i test_mm_mpsadbw_epu8(__m128i x, __m128i y) {
   // CHECK-LABEL: test_mm_mpsadbw_epu8