diff --git a/clang/include/clang/Basic/FixedPoint.h b/clang/include/clang/Basic/FixedPoint.h --- a/clang/include/clang/Basic/FixedPoint.h +++ b/clang/include/clang/Basic/FixedPoint.h @@ -28,8 +28,8 @@ /// The fixed point semantics work similarly to llvm::fltSemantics. The width /// specifies the whole bit width of the underlying scaled integer (with padding /// if any). The scale represents the number of fractional bits in this type. -/// When HasUnsignedPadding is true and this type is signed, the first bit -/// in the value this represents is treaded as padding. +/// When HasUnsignedPadding is true and this type is unsigned, the first bit +/// in the value this represents is treated as padding. class FixedPointSemantics { public: FixedPointSemantics(unsigned Width, unsigned Scale, bool IsSigned, @@ -125,9 +125,10 @@ // Perform binary operations on a fixed point type. The resulting fixed point // value will be in the common, full precision semantics that can represent - // the precision and ranges os both input values. See convert() for an + // the precision and ranges of both input values. See convert() for an // explanation of the Overflow parameter. APFixedPoint add(const APFixedPoint &Other, bool *Overflow = nullptr) const; + APFixedPoint sub(const APFixedPoint &Other, bool *Overflow = nullptr) const; /// Perform a unary negation (-X) on this fixed point type, taking into /// account saturation if applicable. diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp --- a/clang/lib/AST/ExprConstant.cpp +++ b/clang/lib/AST/ExprConstant.cpp @@ -12924,7 +12924,16 @@ case BO_Add: { bool AddOverflow, ConversionOverflow; APFixedPoint Result = LHSFX.add(RHSFX, &AddOverflow) - .convert(ResultFXSema, &ConversionOverflow); + .convert(ResultFXSema, &ConversionOverflow); + if ((AddOverflow || ConversionOverflow) && + !HandleOverflow(Info, E, Result, E->getType())) + return false; + return Success(Result, E); + } + case BO_Sub: { + bool AddOverflow, ConversionOverflow; + APFixedPoint Result = LHSFX.sub(RHSFX, &AddOverflow) + .convert(ResultFXSema, &ConversionOverflow); if ((AddOverflow || ConversionOverflow) && !HandleOverflow(Info, E, Result, E->getType())) return false; diff --git a/clang/lib/Basic/FixedPoint.cpp b/clang/lib/Basic/FixedPoint.cpp --- a/clang/lib/Basic/FixedPoint.cpp +++ b/clang/lib/Basic/FixedPoint.cpp @@ -173,6 +173,30 @@ return APFixedPoint(Result, CommonFXSema); } +APFixedPoint APFixedPoint::sub(const APFixedPoint &Other, + bool *Overflow) const { + auto CommonFXSema = Sema.getCommonSemantics(Other.getSemantics()); + APFixedPoint ConvertedThis = convert(CommonFXSema); + APFixedPoint ConvertedOther = Other.convert(CommonFXSema); + llvm::APSInt ThisVal = ConvertedThis.getValue(); + llvm::APSInt OtherVal = ConvertedOther.getValue(); + bool Overflowed = false; + + llvm::APSInt Result; + if (CommonFXSema.isSaturated()) { + Result = CommonFXSema.isSigned() ? ThisVal.ssub_sat(OtherVal) + : ThisVal.usub_sat(OtherVal); + } else { + Result = ThisVal.isSigned() ? ThisVal.ssub_ov(OtherVal, Overflowed) + : ThisVal.usub_ov(OtherVal, Overflowed); + } + + if (Overflow) + *Overflow = Overflowed; + + return APFixedPoint(Result, CommonFXSema); +} + void APFixedPoint::toString(llvm::SmallVectorImpl &Str) const { llvm::APSInt Val = getValue(); unsigned Scale = getScale(); diff --git a/clang/test/Frontend/fixed_point_sub.c b/clang/test/Frontend/fixed_point_sub.c --- a/clang/test/Frontend/fixed_point_sub.c +++ b/clang/test/Frontend/fixed_point_sub.c @@ -1,6 +1,55 @@ // 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 +// Subtraction between different fixed point types +short _Accum sa_const = 1.0hk - 2.0hk; // CHECK-DAG: @sa_const = {{.*}}global i16 -128, align 2 +_Accum a_const = 1.0hk - 2.0k; // CHECK-DAG: @a_const = {{.*}}global i32 -32768, align 4 +long _Accum la_const = 1.0hk - 2.0lk; // CHECK-DAG: @la_const = {{.*}}global i64 -2147483648, align 8 +short _Accum sa_const2 = 0.5hr - 2.0hk; // CHECK-DAG: @sa_const2 = {{.*}}global i16 -192, align 2 +short _Accum sa_const3 = 0.5r - 2.0hk; // CHECK-DAG: @sa_const3 = {{.*}}global i16 -192, align 2 +short _Accum sa_const4 = 0.5lr - 2.0hk; // CHECK-DAG: @sa_const4 = {{.*}}global i16 -192, align 2 +short _Accum sa_const5 = 2.0hk - 0.5lr; // CHECK-DAG: @sa_const5 = {{.*}}global i16 192, align 2 + +// Unsigned subtraction +unsigned short _Accum usa_const = 3.0uhk - 2.0uhk; +// CHECK-SIGNED-DAG: @usa_const = {{.*}}global i16 768, align 2 +// CHECK-UNSIGNED-DAG: @usa_const = {{.*}}global i16 384, align 2 + +// Unsigned - signed +short _Accum sa_const6 = 1.0uhk - 2.0hk; +// CHECK-DAG: @sa_const6 = {{.*}}global i16 -128, align 2 + +// Subtraction with negative number +short _Accum sa_const7 = 0.5hr - (-2.0hk); +// CHECK-DAG: @sa_const7 = {{.*}}global i16 320, align 2 + +// Int subtraction +unsigned short _Accum usa_const2 = 2 - 0.5uhk; +// CHECK-SIGNED-DAG: @usa_const2 = {{.*}}global i16 640, align 2 +// CHECK-UNSIGNED-DAG: @usa_const2 = {{.*}}global i16 320, align 2 +short _Accum sa_const8 = 2 - (-0.5hk); // CHECK-DAG: @sa_const8 = {{.*}}global i16 320, align 2 +short _Accum sa_const9 = 257 - 2.0hk; // CHECK-DAG: @sa_const9 = {{.*}}global i16 32640, align 2 +long _Fract lf_const = 0.5lr - 1; // CHECK-DAG: @lf_const = {{.*}}global i32 -1073741824, align 4 + +// Saturated subtraction +_Sat short _Accum sat_sa_const = (_Sat short _Accum)128.0hk - (-128.0hk); +// CHECK-DAG: @sat_sa_const = {{.*}}global i16 32767, align 2 +_Sat unsigned short _Accum sat_usa_const = (_Sat unsigned short _Accum)128.0uhk - (-128.0uhk); +// CHECK-SIGNED-DAG: @sat_usa_const = {{.*}}global i16 65535, align 2 +// CHECK-UNSIGNED-DAG: @sat_usa_const = {{.*}}global i16 32767, align 2 +_Sat short _Accum sat_sa_const2 = (_Sat short _Accum)128.0hk - (-128); +// CHECK-DAG: @sat_sa_const2 = {{.*}}global i16 32767, align 2 +_Sat unsigned short _Accum sat_usa_const2 = (_Sat unsigned short _Accum)128.0uhk - (-128); +// CHECK-SIGNED-DAG: @sat_usa_const2 = {{.*}}global i16 65535, align 2 +// CHECK-UNSIGNED-DAG: @sat_usa_const2 = {{.*}}global i16 32767, align 2 +_Sat unsigned short _Accum sat_usa_const3 = (_Sat unsigned short _Accum)0.5uhk - 2; +// CHECK-DAG: @sat_usa_const3 = {{.*}}global i16 0, align 2 +_Sat short _Accum sat_sa_const3 = (_Sat short _Accum)-128.0hk - 128; +// CHECK-DAG: @sat_sa_const3 = {{.*}}global i16 -32768, align 2 +_Sat short _Accum sat_sa_const4 = (_Sat short _Accum)-150.0hk - 130.0lk; +// CHECK-DAG: @sat_sa_const4 = {{.*}}global i16 -32768, align 2 + + void SignedSubtraction() { // CHECK-LABEL: SignedSubtraction short _Accum sa;