[Clang] VectorExprEvaluator::VisitCallExpr / InterpretBuiltin - allow SSE41 phminposuw intrinsic to be used in constexp #163041

kimsh02 · 2025-10-12T05:08:27Z

Fix #161336

llvmbot · 2025-10-12T05:08:59Z

@llvm/pr-subscribers-backend-x86

@llvm/pr-subscribers-clang

Author: Shawn K (kimsh02)

Changes

Fix #161336

Full diff: https://github.com/llvm/llvm-project/pull/163041.diff

5 Files Affected:

(modified) clang/include/clang/Basic/BuiltinsX86.td (+3-2)
(modified) clang/lib/AST/ByteCode/InterpBuiltin.cpp (+44)
(modified) clang/lib/AST/ExprConstant.cpp (+34)
(modified) clang/lib/Headers/smmintrin.h (+2-1)
(modified) clang/test/CodeGen/X86/sse41-builtins.c (+10)

diff --git a/clang/include/clang/Basic/BuiltinsX86.td b/clang/include/clang/Basic/BuiltinsX86.td
index 217589d7add1d..1cd72707bf93f 100644
--- a/clang/include/clang/Basic/BuiltinsX86.td
+++ b/clang/include/clang/Basic/BuiltinsX86.td
@@ -327,8 +327,8 @@ let Features = "sse4.1", Attributes = [NoThrow, Const, RequiredVectorWidth<128>]
   def ptestz128 : X86Builtin<"int(_Vector<2, long long int>, _Vector<2, long long int>)">;
   def ptestc128 : X86Builtin<"int(_Vector<2, long long int>, _Vector<2, long long int>)">;
   def ptestnzc128 : X86Builtin<"int(_Vector<2, long long int>, _Vector<2, long long int>)">;
-  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", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<128>] in {
@@ -341,6 +341,7 @@ 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)">;
diff --git a/clang/lib/AST/ByteCode/InterpBuiltin.cpp b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
index 922d67940e22f..1b3eb4da69ec7 100644
--- a/clang/lib/AST/ByteCode/InterpBuiltin.cpp
+++ b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
@@ -2860,6 +2860,46 @@ 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 ElemPT = S.getContext().classify(ElemQT);
+  unsigned LaneBitWidth = S.getASTContext().getTypeSize(ElemQT);
+
+  INT_TYPE_SWITCH_NO_BOOL(*ElemPT, {
+    APInt MinIndex(LaneBitWidth, 0);
+    APInt MinVal = Source.elem<T>(0).toAPSInt();
+
+    for (unsigned I = 0; I != SourceLen; ++I) {
+      APInt Val = Source.elem<T>(I).toAPSInt();
+      if (MinVal.ugt(Val)) {
+        MinVal = Val;
+        MinIndex = I;
+      }
+    }
+
+    bool DestUnsigned = Call->getCallReturnType(S.getASTContext())
+                            ->castAs<VectorType>()
+                            ->getElementType()
+                            ->isUnsignedIntegerOrEnumerationType();
+
+    Dest.elem<T>(0) = static_cast<T>(APSInt(MinVal, DestUnsigned));
+    Dest.elem<T>(1) = static_cast<T>(APSInt(MinIndex, DestUnsigned));
+    for (unsigned I = 2; I != SourceLen; ++I) {
+      Dest.elem<T>(I) =
+          static_cast<T>(APSInt(APInt(LaneBitWidth, 0), DestUnsigned));
+    }
+  });
+  Dest.initializeAllElements();
+  return true;
+}
+
 static bool interp__builtin_ia32_pternlog(InterpState &S, CodePtr OpPC,
                                           const CallExpr *Call, bool MaskZ) {
   assert(Call->getNumArgs() == 5);
@@ -3809,6 +3849,10 @@ 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:
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 35a866ea5010f..e686d17522260 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -12216,6 +12216,40 @@ 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 LaneBitWidth = Info.Ctx.getTypeSize(ElemQT);
+
+    APInt MinIndex(LaneBitWidth, 0);
+    APInt MinVal = Source.getVectorElt(0).getInt();
+    for (unsigned I = 0; 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(LaneBitWidth, 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:
diff --git a/clang/lib/Headers/smmintrin.h b/clang/lib/Headers/smmintrin.h
index 5e63a1ae321bc..1cc2c7b9371a2 100644
--- a/clang/lib/Headers/smmintrin.h
+++ b/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);
 }
 
diff --git a/clang/test/CodeGen/X86/sse41-builtins.c b/clang/test/CodeGen/X86/sse41-builtins.c
index eee479a755ab4..28b9b83237c88 100644
--- a/clang/test/CodeGen/X86/sse41-builtins.c
+++ b/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

clang/include/clang/Basic/BuiltinsX86.td

clang/lib/AST/ByteCode/InterpBuiltin.cpp

RKSimon

a couple of minors

clang/lib/AST/ByteCode/InterpBuiltin.cpp

clang/lib/AST/ExprConstant.cpp

clang/lib/AST/ByteCode/InterpBuiltin.cpp

clang/lib/AST/ExprConstant.cpp

kimsh02 · 2025-10-15T18:46:46Z

@RKSimon This PR can take a look

RKSimon · 2025-10-17T09:17:57Z

clang/lib/AST/ByteCode/InterpBuiltin.cpp

+                          ->isUnsignedIntegerOrEnumerationType();
+
+  INT_TYPE_SWITCH_NO_BOOL(*ElemT, {
+    APSInt MinIndex(ElemBitWidth, DestUnsigned);


Its probably better to just use:

Suggested change

APSInt MinIndex(ElemBitWidth, DestUnsigned);

unsigned MinIndex = 0;

We never make use of APSInt/APInt features for the index.

kimsh02 · 2025-10-20T13:15:05Z

@RKSimon

llvmbot added clang Clang issues not falling into any other category backend:X86 clang:frontend Language frontend issues, e.g. anything involving "Sema" clang:headers Headers provided by Clang, e.g. for intrinsics clang:bytecode Issues for the clang bytecode constexpr interpreter labels Oct 12, 2025

kimsh02 commented Oct 12, 2025

View reviewed changes

clang/include/clang/Basic/BuiltinsX86.td Show resolved Hide resolved

kimsh02 changed the title ~~X86 phminposuw~~ [Clang] VectorExprEvaluator::VisitCallExpr / InterpretBuiltin - allow SSE41 phminposuw intrinsic to be used in constexp Oct 12, 2025

tbaederr reviewed Oct 12, 2025

View reviewed changes

tbaederr requested a review from RKSimon October 12, 2025 06:16

RKSimon requested changes Oct 13, 2025

View reviewed changes

clang/lib/AST/ByteCode/InterpBuiltin.cpp Outdated Show resolved Hide resolved

clang/lib/AST/ExprConstant.cpp Show resolved Hide resolved

clang/lib/AST/ByteCode/InterpBuiltin.cpp Outdated Show resolved Hide resolved

kimsh02 force-pushed the x86-phminposuw branch from 7427732 to d5d98b0 Compare October 13, 2025 18:51

RKSimon reviewed Oct 14, 2025

View reviewed changes

clang/lib/AST/ByteCode/InterpBuiltin.cpp Outdated Show resolved Hide resolved

kimsh02 added 2 commits October 14, 2025 11:16

Squash

13c9d31

Apply feedback

92e4007

kimsh02 force-pushed the x86-phminposuw branch from 0b5295c to 92e4007 Compare October 14, 2025 18:23

RKSimon reviewed Oct 14, 2025

View reviewed changes

clang/lib/AST/ExprConstant.cpp Outdated Show resolved Hide resolved

kimsh02 added 2 commits October 14, 2025 12:34

Apply feedback

5eace3e

Merge branch 'main' into x86-phminposuw

def1dea

kimsh02 and others added 2 commits October 16, 2025 13:26

Merge branch 'main' into x86-phminposuw

c32f4bb

Merge branch 'main' into x86-phminposuw

91c64fa

RKSimon requested changes Oct 17, 2025

View reviewed changes

kimsh02 added 3 commits October 17, 2025 15:08

Merge branch 'main' into x86-phminposuw

04f5270

Merge branch 'main' into x86-phminposuw

8435a9f

Merge branch 'main' into x86-phminposuw

7aff2b7

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

[Clang] VectorExprEvaluator::VisitCallExpr / InterpretBuiltin - allow SSE41 phminposuw intrinsic to be used in constexp #163041

[Clang] VectorExprEvaluator::VisitCallExpr / InterpretBuiltin - allow SSE41 phminposuw intrinsic to be used in constexp #163041

kimsh02 commented Oct 12, 2025

Uh oh!

llvmbot commented Oct 12, 2025 •

edited

Loading

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

RKSimon left a comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

kimsh02 commented Oct 15, 2025

Uh oh!

RKSimon Oct 17, 2025

Uh oh!

kimsh02 commented Oct 20, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

	APSInt MinIndex(ElemBitWidth, DestUnsigned);
	unsigned MinIndex = 0;

[Clang] VectorExprEvaluator::VisitCallExpr / InterpretBuiltin - allow SSE41 phminposuw intrinsic to be used in constexp #163041

Are you sure you want to change the base?

[Clang] VectorExprEvaluator::VisitCallExpr / InterpretBuiltin - allow SSE41 phminposuw intrinsic to be used in constexp #163041

Conversation

kimsh02 commented Oct 12, 2025

Uh oh!

llvmbot commented Oct 12, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

RKSimon left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

kimsh02 commented Oct 15, 2025

Uh oh!

RKSimon Oct 17, 2025

Choose a reason for hiding this comment

Uh oh!

kimsh02 commented Oct 20, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

llvmbot commented Oct 12, 2025 •

edited

Loading