[Clang] Add elementwise ldexp builtin function

[wenju-he]

This PR adds __builtin_elementwise_ldexp. It can be used for implementing OpenCL ldexp builtin with vector inputs.

[llvmbot]

@llvm/pr-subscribers-clang-codegen

@llvm/pr-subscribers-clang

Author: Wenju He (wenju-he)

Changes

This PR adds __builtin_elementwise_ldexp. It can be used for implementing OpenCL ldexp builtin with vector inputs.

---

Full diff: https://github.com/llvm/llvm-project/pull/166296.diff

7 Files Affected:

• (modified) clang/docs/LanguageExtensions.rst (+2)
• (modified) clang/docs/ReleaseNotes.rst (+2)
• (modified) clang/include/clang/Basic/Builtins.td (+6)
• (modified) clang/lib/CodeGen/CGBuiltin.cpp (+6)
• (modified) clang/lib/Sema/SemaChecking.cpp (+52-12)
• (modified) clang/test/CodeGen/builtins-elementwise-math.c (+31)
• (modified) clang/test/Sema/builtins-elementwise-math.c (+36)

diff --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst
index 495f2ab3926ce..ed3573012d680 100644
--- a/clang/docs/LanguageExtensions.rst
+++ b/clang/docs/LanguageExtensions.rst
@@ -805,6 +805,8 @@ of different sizes and signs is forbidden in binary and ternary builtins.
  T __builtin_elementwise_exp(T x)               returns the base-e exponential, e^x, of the specified value            floating point types
  T __builtin_elementwise_exp2(T x)              returns the base-2 exponential, 2^x, of the specified value            floating point types
  T __builtin_elementwise_exp10(T x)             returns the base-10 exponential, 10^x, of the specified value          floating point types
+ T __builtin_elementwise_ldexp(T x, IntT y)     returns the product of x and 2 raised to the power y. The              floating point types
+                                                number of elements in y must equal the number of elements in x.
 
  T __builtin_elementwise_sqrt(T x)              return the square root of a floating-point number                      floating point types
  T __builtin_elementwise_roundeven(T x)         round x to the nearest integer value in floating point format,         floating point types
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 92fc9381a5868..1d9021dfc6017 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -207,6 +207,8 @@ C23 Feature Support
 
 Non-comprehensive list of changes in this release
 -------------------------------------------------
+- Added ``__builtin_elementwise_ldexp``.
+
 - Added ``__builtin_elementwise_fshl`` and ``__builtin_elementwise_fshr``.
 
 - ``__builtin_elementwise_abs`` can now be used in constant expression.
diff --git a/clang/include/clang/Basic/Builtins.td b/clang/include/clang/Basic/Builtins.td
index 2b400b012d6ed..9b8f7864329a9 100644
--- a/clang/include/clang/Basic/Builtins.td
+++ b/clang/include/clang/Basic/Builtins.td
@@ -1418,6 +1418,12 @@ def ElementwiseExp10 : Builtin {
   let Prototype = "void(...)";
 }
 
+def ElementwiseLdexp : Builtin {
+  let Spellings = ["__builtin_elementwise_ldexp"];
+  let Attributes = [NoThrow, Const, CustomTypeChecking];
+  let Prototype = "void(...)";
+}
+
 def ElementwiseFloor : Builtin {
   let Spellings = ["__builtin_elementwise_floor"];
   let Attributes = [NoThrow, Const, CustomTypeChecking];
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index b81e0d02da2c9..bbcee34b384c0 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -3992,6 +3992,12 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
   case Builtin::BI__builtin_elementwise_exp10:
     return RValue::get(emitBuiltinWithOneOverloadedType<1>(
         *this, E, Intrinsic::exp10, "elt.exp10"));
+  case Builtin::BI__builtin_elementwise_ldexp: {
+    Value *Src = EmitScalarExpr(E->getArg(0));
+    Value *Exp = EmitScalarExpr(E->getArg(1));
+    Value *Result = Builder.CreateLdexp(Src, Exp, {}, "elt.ldexp");
+    return RValue::get(Result);
+  }
   case Builtin::BI__builtin_elementwise_log:
     return RValue::get(emitBuiltinWithOneOverloadedType<1>(
         *this, E, Intrinsic::log, "elt.log"));
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index ad2c2e4a97bb9..a8e3fe6c07b12 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -2609,6 +2609,18 @@ static ExprResult BuiltinInvoke(Sema &S, CallExpr *TheCall) {
                          Args.drop_front(), TheCall->getRParenLoc());
 }
 
+// Performs a similar job to Sema::UsualUnaryConversions, but without any
+// implicit promotion of integral/enumeration types.
+static ExprResult BuiltinVectorMathConversions(Sema &S, Expr *E) {
+  // First, convert to an r-value.
+  ExprResult Res = S.DefaultFunctionArrayLvalueConversion(E);
+  if (Res.isInvalid())
+    return ExprError();
+
+  // Promote floating-point types.
+  return S.UsualUnaryFPConversions(Res.get());
+}
+
 ExprResult
 Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl, unsigned BuiltinID,
                                CallExpr *TheCall) {
@@ -3273,6 +3285,46 @@ Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl, unsigned BuiltinID,
       return ExprError();
     break;
 
+  case Builtin::BI__builtin_elementwise_ldexp: {
+    if (checkArgCount(TheCall, 2))
+      return ExprError();
+
+    ExprResult A = BuiltinVectorMathConversions(*this, TheCall->getArg(0));
+    if (A.isInvalid())
+      return ExprError();
+    QualType TyA = A.get()->getType();
+    if (checkMathBuiltinElementType(*this, A.get()->getBeginLoc(), TyA,
+                                    EltwiseBuiltinArgTyRestriction::FloatTy, 1))
+      return ExprError();
+
+    ExprResult Exp = UsualUnaryConversions(TheCall->getArg(1));
+    if (Exp.isInvalid())
+      return ExprError();
+    QualType TyExp = Exp.get()->getType();
+    if (checkMathBuiltinElementType(*this, Exp.get()->getBeginLoc(), TyExp,
+                                    EltwiseBuiltinArgTyRestriction::IntegerTy,
+                                    2))
+      return ExprError();
+
+    // Check the two arguments are either scalars or vectors of equal length.
+    const auto *Vec0 = TyA->getAs<VectorType>();
+    const auto *Vec1 = TyExp->getAs<VectorType>();
+    unsigned Arg0Length = Vec0 ? Vec0->getNumElements() : 0;
+    unsigned Arg1Length = Vec1 ? Vec1->getNumElements() : 0;
+    if (Arg0Length != Arg1Length) {
+      Diag(Exp.get()->getBeginLoc(),
+           diag::err_typecheck_vector_lengths_not_equal)
+          << TyA << TyExp << A.get()->getSourceRange()
+          << Exp.get()->getSourceRange();
+      return ExprError();
+    }
+
+    TheCall->setArg(0, A.get());
+    TheCall->setArg(1, Exp.get());
+    TheCall->setType(TyA);
+    break;
+  }
+
   // These builtins restrict the element type to floating point
   // types only, and take in two arguments.
   case Builtin::BI__builtin_elementwise_minnum:
@@ -15992,18 +16044,6 @@ void Sema::CheckAddressOfPackedMember(Expr *rhs) {
                      _2, _3, _4));
 }
 
-// Performs a similar job to Sema::UsualUnaryConversions, but without any
-// implicit promotion of integral/enumeration types.
-static ExprResult BuiltinVectorMathConversions(Sema &S, Expr *E) {
-  // First, convert to an r-value.
-  ExprResult Res = S.DefaultFunctionArrayLvalueConversion(E);
-  if (Res.isInvalid())
-    return ExprError();
-
-  // Promote floating-point types.
-  return S.UsualUnaryFPConversions(Res.get());
-}
-
 bool Sema::PrepareBuiltinElementwiseMathOneArgCall(
     CallExpr *TheCall, EltwiseBuiltinArgTyRestriction ArgTyRestr) {
   if (checkArgCount(TheCall, 1))
diff --git a/clang/test/CodeGen/builtins-elementwise-math.c b/clang/test/CodeGen/builtins-elementwise-math.c
index e9344d8fe0b8b..2df485f0155c3 100644
--- a/clang/test/CodeGen/builtins-elementwise-math.c
+++ b/clang/test/CodeGen/builtins-elementwise-math.c
@@ -6,6 +6,7 @@ typedef half half2 __attribute__((ext_vector_type(2)));
 typedef float float2 __attribute__((ext_vector_type(2)));
 typedef float float4 __attribute__((ext_vector_type(4)));
 typedef short int si8 __attribute__((ext_vector_type(8)));
+typedef int int4 __attribute__((ext_vector_type(4)));
 typedef unsigned int u4 __attribute__((ext_vector_type(4)));
 typedef double double2 __attribute__((ext_vector_type(2)));
 typedef double double3 __attribute__((ext_vector_type(3)));
@@ -729,6 +730,36 @@ void test_builtin_elementwise_exp10(float f1, float f2, double d1, double d2,
   vf2 = __builtin_elementwise_exp10(vf1);
 }
 
+void test_builtin_elementwise_ldexp(float f1, float f2, double d1, double d2,
+                                    float4 vf1, float4 vf2, int i1, int4 vi1, short s1, long l1) {
+  // CHECK-LABEL: define void @test_builtin_elementwise_ldexp(
+  // CHECK:      [[F1:%.+]] = load float, ptr %f1.addr, align 4
+  // CHECK:      [[I1:%.+]] = load i32, ptr %i1.addr, align 4
+  // CHECK-NEXT: call float @llvm.ldexp.f32.i32(float [[F1]], i32 [[I1]])
+  f2 = __builtin_elementwise_ldexp(f1, i1);
+
+  // CHECK:      [[F2:%.+]] = load float, ptr %f1.addr, align 4
+  // CHECK:      [[S1:%.+]] = load i16, ptr %s1.addr, align 2
+  // CHECK:      [[Ext1:%.+]] = sext i16 [[S1]] to i32
+  // CHECK-NEXT: call float @llvm.ldexp.f32.i32(float [[F2]], i32 [[Ext1]])
+  f2 = __builtin_elementwise_ldexp(f1, s1);
+
+  // CHECK:      [[F3:%.+]] = load float, ptr %f1.addr, align 4
+  // CHECK:      [[L1:%.+]] = load i64, ptr %l1.addr, align 8
+  // CHECK-NEXT: call float @llvm.ldexp.f32.i64(float [[F3]], i64 [[L1]])
+  f2 = __builtin_elementwise_ldexp(f1, l1);
+
+  // CHECK:      [[D1:%.+]] = load double, ptr %d1.addr, align 8
+  // CHECK:      [[I2:%.+]] = load i32, ptr %i1.addr, align 4
+  // CHECK-NEXT: call double @llvm.ldexp.f64.i32(double [[D1]], i32 [[I2]])
+  d2 = __builtin_elementwise_ldexp(d1, i1);
+
+  // CHECK:      [[VF1:%.+]] = load <4 x float>, ptr %vf1.addr, align 16
+  // CHECK:      [[VI1:%.+]] = load <4 x i32>, ptr %vi1.addr, align 16
+  // CHECK-NEXT: call <4 x float> @llvm.ldexp.v4f32.v4i32(<4 x float> [[VF1]], <4 x i32> [[VI1]])
+  vf2 = __builtin_elementwise_ldexp(vf1, vi1);
+}
+
 void test_builtin_elementwise_floor(float f1, float f2, double d1, double d2,
                                     float4 vf1, float4 vf2) {
   // CHECK-LABEL: define void @test_builtin_elementwise_floor(
diff --git a/clang/test/Sema/builtins-elementwise-math.c b/clang/test/Sema/builtins-elementwise-math.c
index f9df4a6f93e05..37be0e4ebbd28 100644
--- a/clang/test/Sema/builtins-elementwise-math.c
+++ b/clang/test/Sema/builtins-elementwise-math.c
@@ -645,6 +645,42 @@ void test_builtin_elementwise_exp10(int i, float f, double d, float4 v, int3 iv,
   // expected-error@-1 {{1st argument must be a scalar or vector of floating-point types (was 'unsigned4' (vector of 4 'unsigned int' values))}}
 }
 
+void test_builtin_elementwise_ldexp(int i, float f, double d, float4 v, int3 iv, unsigned u, unsigned4 uv) {
+
+  struct Foo s = __builtin_elementwise_ldexp(f, i);
+  // expected-error@-1 {{initializing 'struct Foo' with an expression of incompatible type 'float'}}
+
+  f = __builtin_elementwise_ldexp();
+  // expected-error@-1 {{too few arguments to function call, expected 2, have 0}}
+
+  f = __builtin_elementwise_ldexp(f);
+  // expected-error@-1 {{too few arguments to function call, expected 2, have 1}}
+
+  f = __builtin_elementwise_ldexp(f, i, i);
+  // expected-error@-1 {{too many arguments to function call, expected 2, have 3}}
+
+  f = __builtin_elementwise_ldexp(i, i);
+  // expected-error@-1 {{1st argument must be a scalar or vector of floating-point types (was 'int')}}
+
+  f = __builtin_elementwise_ldexp(f, f);
+  // expected-error@-1 {{2nd argument must be a scalar or vector of integer types (was 'float')}}
+
+  f = __builtin_elementwise_ldexp(v, iv);
+  // expected-error@-1 {{vector operands do not have the same number of elements ('float4' (vector of 4 'float' values) and 'int3' (vector of 3 'int' values))}}
+
+  v = __builtin_elementwise_ldexp(v, i);
+  // expected-error@-1 {{vector operands do not have the same number of elements ('float4' (vector of 4 'float' values) and 'int')}}
+
+  v = __builtin_elementwise_ldexp(f, iv);
+  // expected-error@-1 {{vector operands do not have the same number of elements ('float' and 'int3' (vector of 3 'int' values))}}
+
+  f = __builtin_elementwise_ldexp(u, i);
+  // expected-error@-1 {{1st argument must be a scalar or vector of floating-point types (was 'unsigned int')}}
+
+  f = __builtin_elementwise_ldexp(uv, i);
+  // expected-error@-1 {{1st argument must be a scalar or vector of floating-point types (was 'unsigned4' (vector of 4 'unsigned int' values))}}
+}
+
 void test_builtin_elementwise_floor(int i, float f, double d, float4 v, int3 iv, unsigned u, unsigned4 uv) {
 
   struct Foo s = __builtin_elementwise_floor(f);

[AaronBallman]

LGTM!