[clang] [clang][Interp] Implement Complex-complex multiplication (PR #94891)
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Sat Jun 8 23:25:46 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang
Author: Timm Baeder (tbaederr)
<details>
<summary>Changes</summary>
Share the implementation for floating-point complex-complex multiplication with the current interpreter. This means we need a new opcode for this, but there's no good way around that.
---
Full diff: https://github.com/llvm/llvm-project/pull/94891.diff
6 Files Affected:
- (modified) clang/lib/AST/ExprConstShared.h (+7)
- (modified) clang/lib/AST/ExprConstant.cpp (+57-49)
- (modified) clang/lib/AST/Interp/ByteCodeExprGen.cpp (+45-10)
- (modified) clang/lib/AST/Interp/Interp.h (+57)
- (modified) clang/lib/AST/Interp/Opcodes.td (+4)
- (modified) clang/test/AST/Interp/complex.cpp (+31)
``````````diff
diff --git a/clang/lib/AST/ExprConstShared.h b/clang/lib/AST/ExprConstShared.h
index a97eac85abc69..9decd47e41767 100644
--- a/clang/lib/AST/ExprConstShared.h
+++ b/clang/lib/AST/ExprConstShared.h
@@ -14,6 +14,9 @@
#ifndef LLVM_CLANG_LIB_AST_EXPRCONSTSHARED_H
#define LLVM_CLANG_LIB_AST_EXPRCONSTSHARED_H
+namespace llvm {
+class APFloat;
+}
namespace clang {
class QualType;
class LangOptions;
@@ -56,4 +59,8 @@ enum class GCCTypeClass {
GCCTypeClass EvaluateBuiltinClassifyType(QualType T,
const LangOptions &LangOpts);
+void HandleComplexComplexMul(llvm::APFloat A, llvm::APFloat B, llvm::APFloat C,
+ llvm::APFloat D, llvm::APFloat &ResR,
+ llvm::APFloat &ResI);
+
#endif
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 86fb396fabe2d..7c597a238f041 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -15126,6 +15126,62 @@ bool ComplexExprEvaluator::VisitCastExpr(const CastExpr *E) {
llvm_unreachable("unknown cast resulting in complex value");
}
+void HandleComplexComplexMul(APFloat A, APFloat B, APFloat C, APFloat D,
+ APFloat &ResR, APFloat &ResI) {
+ // This is an implementation of complex multiplication according to the
+ // constraints laid out in C11 Annex G. The implementation uses the
+ // following naming scheme:
+ // (a + ib) * (c + id)
+
+ APFloat AC = A * C;
+ APFloat BD = B * D;
+ APFloat AD = A * D;
+ APFloat BC = B * C;
+ ResR = AC - BD;
+ ResI = AD + BC;
+ if (ResR.isNaN() && ResI.isNaN()) {
+ bool Recalc = false;
+ if (A.isInfinity() || B.isInfinity()) {
+ A = APFloat::copySign(APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0),
+ A);
+ B = APFloat::copySign(APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0),
+ B);
+ if (C.isNaN())
+ C = APFloat::copySign(APFloat(C.getSemantics()), C);
+ if (D.isNaN())
+ D = APFloat::copySign(APFloat(D.getSemantics()), D);
+ Recalc = true;
+ }
+ if (C.isInfinity() || D.isInfinity()) {
+ C = APFloat::copySign(APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0),
+ C);
+ D = APFloat::copySign(APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0),
+ D);
+ if (A.isNaN())
+ A = APFloat::copySign(APFloat(A.getSemantics()), A);
+ if (B.isNaN())
+ B = APFloat::copySign(APFloat(B.getSemantics()), B);
+ Recalc = true;
+ }
+ if (!Recalc && (AC.isInfinity() || BD.isInfinity() || AD.isInfinity() ||
+ BC.isInfinity())) {
+ if (A.isNaN())
+ A = APFloat::copySign(APFloat(A.getSemantics()), A);
+ if (B.isNaN())
+ B = APFloat::copySign(APFloat(B.getSemantics()), B);
+ if (C.isNaN())
+ C = APFloat::copySign(APFloat(C.getSemantics()), C);
+ if (D.isNaN())
+ D = APFloat::copySign(APFloat(D.getSemantics()), D);
+ Recalc = true;
+ }
+ if (Recalc) {
+ ResR = APFloat::getInf(A.getSemantics()) * (A * C - B * D);
+ ResI = APFloat::getInf(A.getSemantics()) * (A * D + B * C);
+ }
+ }
+}
+
bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
@@ -15225,55 +15281,7 @@ bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
!handleFloatFloatBinOp(Info, E, ResI, BO_Mul, B))
return false;
} else {
- // In the fully general case, we need to handle NaNs and infinities
- // robustly.
- APFloat AC = A * C;
- APFloat BD = B * D;
- APFloat AD = A * D;
- APFloat BC = B * C;
- ResR = AC - BD;
- ResI = AD + BC;
- if (ResR.isNaN() && ResI.isNaN()) {
- bool Recalc = false;
- if (A.isInfinity() || B.isInfinity()) {
- A = APFloat::copySign(
- APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A);
- B = APFloat::copySign(
- APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B);
- if (C.isNaN())
- C = APFloat::copySign(APFloat(C.getSemantics()), C);
- if (D.isNaN())
- D = APFloat::copySign(APFloat(D.getSemantics()), D);
- Recalc = true;
- }
- if (C.isInfinity() || D.isInfinity()) {
- C = APFloat::copySign(
- APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C);
- D = APFloat::copySign(
- APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D);
- if (A.isNaN())
- A = APFloat::copySign(APFloat(A.getSemantics()), A);
- if (B.isNaN())
- B = APFloat::copySign(APFloat(B.getSemantics()), B);
- Recalc = true;
- }
- if (!Recalc && (AC.isInfinity() || BD.isInfinity() ||
- AD.isInfinity() || BC.isInfinity())) {
- if (A.isNaN())
- A = APFloat::copySign(APFloat(A.getSemantics()), A);
- if (B.isNaN())
- B = APFloat::copySign(APFloat(B.getSemantics()), B);
- if (C.isNaN())
- C = APFloat::copySign(APFloat(C.getSemantics()), C);
- if (D.isNaN())
- D = APFloat::copySign(APFloat(D.getSemantics()), D);
- Recalc = true;
- }
- if (Recalc) {
- ResR = APFloat::getInf(A.getSemantics()) * (A * C - B * D);
- ResI = APFloat::getInf(A.getSemantics()) * (A * D + B * C);
- }
- }
+ HandleComplexComplexMul(A, B, C, D, ResR, ResI);
}
} else {
ComplexValue LHS = Result;
diff --git a/clang/lib/AST/Interp/ByteCodeExprGen.cpp b/clang/lib/AST/Interp/ByteCodeExprGen.cpp
index ff2b51e3fb6fa..2fa479b818064 100644
--- a/clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ b/clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -854,6 +854,22 @@ bool ByteCodeExprGen<Emitter>::VisitComplexBinOp(const BinaryOperator *E) {
if (const auto *AT = RHSType->getAs<AtomicType>())
RHSType = AT->getValueType();
+ // For ComplexComplex Mul, we have special ops to make their implementation
+ // easier.
+ BinaryOperatorKind Op = E->getOpcode();
+ if (Op == BO_Mul && LHSType->isAnyComplexType() &&
+ RHSType->isAnyComplexType()) {
+ assert(classifyPrim(LHSType->getAs<ComplexType>()->getElementType()) ==
+ classifyPrim(RHSType->getAs<ComplexType>()->getElementType()));
+ PrimType ElemT =
+ classifyPrim(LHSType->getAs<ComplexType>()->getElementType());
+ if (!this->visit(LHS))
+ return false;
+ if (!this->visit(RHS))
+ return false;
+ return this->emitMulc(ElemT, E);
+ }
+
// Evaluate LHS and save value to LHSOffset.
bool LHSIsComplex;
unsigned LHSOffset;
@@ -897,22 +913,22 @@ bool ByteCodeExprGen<Emitter>::VisitComplexBinOp(const BinaryOperator *E) {
// For both LHS and RHS, either load the value from the complex pointer, or
// directly from the local variable. For index 1 (i.e. the imaginary part),
// just load 0 and do the operation anyway.
- auto loadComplexValue = [this](bool IsComplex, unsigned ElemIndex,
- unsigned Offset, const Expr *E) -> bool {
+ auto loadComplexValue = [this](bool IsComplex, bool LoadZero,
+ unsigned ElemIndex, unsigned Offset,
+ const Expr *E) -> bool {
if (IsComplex) {
if (!this->emitGetLocal(PT_Ptr, Offset, E))
return false;
return this->emitArrayElemPop(classifyComplexElementType(E->getType()),
ElemIndex, E);
}
- if (ElemIndex == 0)
+ if (ElemIndex == 0 || !LoadZero)
return this->emitGetLocal(classifyPrim(E->getType()), Offset, E);
return this->visitZeroInitializer(classifyPrim(E->getType()), E->getType(),
E);
};
// Now we can get pointers to the LHS and RHS from the offsets above.
- BinaryOperatorKind Op = E->getOpcode();
for (unsigned ElemIndex = 0; ElemIndex != 2; ++ElemIndex) {
// Result pointer for the store later.
if (!this->DiscardResult) {
@@ -920,15 +936,14 @@ bool ByteCodeExprGen<Emitter>::VisitComplexBinOp(const BinaryOperator *E) {
return false;
}
- if (!loadComplexValue(LHSIsComplex, ElemIndex, LHSOffset, LHS))
- return false;
-
- if (!loadComplexValue(RHSIsComplex, ElemIndex, RHSOffset, RHS))
- return false;
-
// The actual operation.
switch (Op) {
case BO_Add:
+ if (!loadComplexValue(LHSIsComplex, true, ElemIndex, LHSOffset, LHS))
+ return false;
+
+ if (!loadComplexValue(RHSIsComplex, true, ElemIndex, RHSOffset, RHS))
+ return false;
if (ResultElemT == PT_Float) {
if (!this->emitAddf(getRoundingMode(E), E))
return false;
@@ -938,6 +953,11 @@ bool ByteCodeExprGen<Emitter>::VisitComplexBinOp(const BinaryOperator *E) {
}
break;
case BO_Sub:
+ if (!loadComplexValue(LHSIsComplex, true, ElemIndex, LHSOffset, LHS))
+ return false;
+
+ if (!loadComplexValue(RHSIsComplex, true, ElemIndex, RHSOffset, RHS))
+ return false;
if (ResultElemT == PT_Float) {
if (!this->emitSubf(getRoundingMode(E), E))
return false;
@@ -946,6 +966,21 @@ bool ByteCodeExprGen<Emitter>::VisitComplexBinOp(const BinaryOperator *E) {
return false;
}
break;
+ case BO_Mul:
+ if (!loadComplexValue(LHSIsComplex, false, ElemIndex, LHSOffset, LHS))
+ return false;
+
+ if (!loadComplexValue(RHSIsComplex, false, ElemIndex, RHSOffset, RHS))
+ return false;
+
+ if (ResultElemT == PT_Float) {
+ if (!this->emitMulf(getRoundingMode(E), E))
+ return false;
+ } else {
+ if (!this->emitMul(ResultElemT, E))
+ return false;
+ }
+ break;
default:
return false;
diff --git a/clang/lib/AST/Interp/Interp.h b/clang/lib/AST/Interp/Interp.h
index f63711da90c7e..116a9c799a639 100644
--- a/clang/lib/AST/Interp/Interp.h
+++ b/clang/lib/AST/Interp/Interp.h
@@ -13,6 +13,7 @@
#ifndef LLVM_CLANG_AST_INTERP_INTERP_H
#define LLVM_CLANG_AST_INTERP_INTERP_H
+#include "../ExprConstShared.h"
#include "Boolean.h"
#include "Floating.h"
#include "Function.h"
@@ -368,6 +369,62 @@ inline bool Mulf(InterpState &S, CodePtr OpPC, llvm::RoundingMode RM) {
S.Stk.push<Floating>(Result);
return CheckFloatResult(S, OpPC, Result, Status);
}
+
+template <PrimType Name, class T = typename PrimConv<Name>::T>
+inline bool Mulc(InterpState &S, CodePtr OpPC) {
+ const Pointer &RHS = S.Stk.pop<Pointer>();
+ const Pointer &LHS = S.Stk.pop<Pointer>();
+ const Pointer &Result = S.Stk.peek<Pointer>();
+
+ if constexpr (std::is_same_v<T, Floating>) {
+ APFloat A = LHS.atIndex(0).deref<Floating>().getAPFloat();
+ APFloat B = LHS.atIndex(1).deref<Floating>().getAPFloat();
+ APFloat C = RHS.atIndex(0).deref<Floating>().getAPFloat();
+ APFloat D = RHS.atIndex(1).deref<Floating>().getAPFloat();
+
+ APFloat ResR(A.getSemantics());
+ APFloat ResI(A.getSemantics());
+ HandleComplexComplexMul(A, B, C, D, ResR, ResI);
+
+ // Copy into the result.
+ Result.atIndex(0).deref<Floating>() = Floating(ResR);
+ Result.atIndex(0).initialize();
+ Result.atIndex(1).deref<Floating>() = Floating(ResI);
+ Result.atIndex(1).initialize();
+ Result.initialize();
+ } else {
+ // Integer element type.
+ const T &LHSR = LHS.atIndex(0).deref<T>();
+ const T &LHSI = LHS.atIndex(1).deref<T>();
+ const T &RHSR = RHS.atIndex(0).deref<T>();
+ const T &RHSI = RHS.atIndex(1).deref<T>();
+ unsigned Bits = LHSR.bitWidth();
+
+ // real(Result) = (real(LHS) * real(RHS)) - (imag(LHS) * imag(RHS))
+ T A;
+ if (T::mul(LHSR, RHSR, Bits, &A))
+ return false;
+ T B;
+ if (T::mul(LHSI, RHSI, Bits, &B))
+ return false;
+ if (T::sub(A, B, Bits, &Result.atIndex(0).deref<T>()))
+ return false;
+ Result.atIndex(0).initialize();
+
+ // imag(Result) = (real(LHS) * imag(RHS)) + (imag(LHS) * real(RHS))
+ if (T::mul(LHSR, RHSI, Bits, &A))
+ return false;
+ if (T::mul(LHSI, RHSR, Bits, &B))
+ return false;
+ if (T::add(A, B, Bits, &Result.atIndex(1).deref<T>()))
+ return false;
+ Result.atIndex(1).initialize();
+ Result.initialize();
+ }
+
+ return true;
+}
+
/// 1) Pops the RHS from the stack.
/// 2) Pops the LHS from the stack.
/// 3) Pushes 'LHS & RHS' on the stack
diff --git a/clang/lib/AST/Interp/Opcodes.td b/clang/lib/AST/Interp/Opcodes.td
index a5ac8206104c8..c9884476e48b9 100644
--- a/clang/lib/AST/Interp/Opcodes.td
+++ b/clang/lib/AST/Interp/Opcodes.td
@@ -537,6 +537,10 @@ def Sub : AluOpcode;
def Subf : FloatOpcode;
def Mul : AluOpcode;
def Mulf : FloatOpcode;
+def Mulc : Opcode {
+ let Types = [NumberTypeClass];
+ let HasGroup = 1;
+}
def Rem : IntegerOpcode;
def Div : IntegerOpcode;
def Divf : FloatOpcode;
diff --git a/clang/test/AST/Interp/complex.cpp b/clang/test/AST/Interp/complex.cpp
index 09cb620d7b7c3..f6ed9a643a99e 100644
--- a/clang/test/AST/Interp/complex.cpp
+++ b/clang/test/AST/Interp/complex.cpp
@@ -9,6 +9,37 @@ static_assert(&__imag z1 == &__real z1 + 1, "");
static_assert((*(&__imag z1)) == __imag z1, "");
static_assert((*(&__real z1)) == __real z1, "");
+
+static_assert(((1.25 + 0.5j) * (0.25 - 0.75j)) == (0.6875 - 0.8125j), "");
+static_assert(((1.25 + 0.5j) * 0.25) == (0.3125 + 0.125j), "");
+static_assert((1.25 * (0.25 - 0.75j)) == (0.3125 - 0.9375j), "");
+constexpr _Complex float InfC = {1.0, __builtin_inf()};
+constexpr _Complex float InfInf = __builtin_inf() + InfC;
+static_assert(__real__(InfInf) == __builtin_inf());
+static_assert(__imag__(InfInf) == __builtin_inf());
+static_assert(__builtin_isnan(__real__(InfInf * InfInf)));
+static_assert(__builtin_isinf_sign(__imag__(InfInf * InfInf)) == 1);
+
+static_assert(__builtin_isinf_sign(__real__((__builtin_inf() + 1.0j) * 1.0)) == 1);
+static_assert(__builtin_isinf_sign(__imag__((1.0 + InfC) * 1.0)) == 1);
+static_assert(__builtin_isinf_sign(__real__(1.0 * (__builtin_inf() + 1.0j))) == 1);
+static_assert(__builtin_isinf_sign(__imag__(1.0 * (1.0 + InfC))) == 1);
+static_assert(__builtin_isinf_sign(__real__((__builtin_inf() + 1.0j) * (1.0 + 1.0j))) == 1);
+static_assert(__builtin_isinf_sign(__real__((1.0 + 1.0j) * (__builtin_inf() + 1.0j))) == 1);
+static_assert(__builtin_isinf_sign(__real__((__builtin_inf() + 1.0j) * (__builtin_inf() + 1.0j))) == 1);
+static_assert(__builtin_isinf_sign(__real__((1.0 + InfC) * (1.0 + 1.0j))) == -1);
+static_assert(__builtin_isinf_sign(__imag__((1.0 + InfC) * (1.0 + 1.0j))) == 1);
+static_assert(__builtin_isinf_sign(__real__((1.0 + 1.0j) * (1.0 + InfC))) == -1);
+static_assert(__builtin_isinf_sign(__imag__((1.0 + 1.0j) * (1.0 + InfC))) == 1);
+static_assert(__builtin_isinf_sign(__real__((1.0 + InfC) * (1.0 + InfC))) == -1);
+static_assert(__builtin_isinf_sign(__real__(InfInf * InfInf)) == 0);
+
+constexpr _Complex int IIMA = {1,2};
+constexpr _Complex int IIMB = {10,20};
+constexpr _Complex int IIMC = IIMA * IIMB;
+static_assert(__real(IIMC) == -30, "");
+static_assert(__imag(IIMC) == 40, "");
+
constexpr _Complex int Comma1 = {1, 2};
constexpr _Complex int Comma2 = (0, Comma1);
static_assert(Comma1 == Comma1, "");
``````````
</details>
https://github.com/llvm/llvm-project/pull/94891
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