This revision was automatically updated to reflect the committed changes.
Closed by commit rG53f5c8b4a14c: [AST] Add fixed-point multiplication constant
evaluation. (authored by ebevhan).
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D73186/new/
https://reviews.llvm.org/D73186
Files:
clang/include/clang/Basic/FixedPoint.h
clang/lib/AST/ExprConstant.cpp
clang/lib/Basic/FixedPoint.cpp
clang/test/Frontend/fixed_point_mul.c
Index: clang/test/Frontend/fixed_point_mul.c
===================================================================
--- clang/test/Frontend/fixed_point_mul.c
+++ clang/test/Frontend/fixed_point_mul.c
@@ -1,6 +1,49 @@
// RUN: %clang_cc1 -ffixed-point -triple x86_64-unknown-linux-gnu -S -emit-llvm %s -o - | FileCheck %s --check-prefixes=CHECK,SIGNED
// RUN: %clang_cc1 -ffixed-point -triple x86_64-unknown-linux-gnu -fpadding-on-unsigned-fixed-point -S -emit-llvm %s -o - | FileCheck %s --check-prefixes=CHECK,UNSIGNED
+// Multiplication between different fixed point types
+short _Accum sa_const = 2.0hk * 2.0hk; // CHECK-DAG: @sa_const = {{.*}}global i16 512, align 2
+_Accum a_const = 3.0hk * 2.0k; // CHECK-DAG: @a_const = {{.*}}global i32 196608, align 4
+long _Accum la_const = 4.0hk * 2.0lk; // CHECK-DAG: @la_const = {{.*}}global i64 17179869184, align 8
+short _Accum sa_const2 = 0.5hr * 2.0hk; // CHECK-DAG: @sa_const2 = {{.*}}global i16 128, align 2
+short _Accum sa_const3 = 0.5r * 3.0hk; // CHECK-DAG: @sa_const3 = {{.*}}global i16 192, align 2
+short _Accum sa_const4 = 0.5lr * 4.0hk; // CHECK-DAG: @sa_const4 = {{.*}}global i16 256, align 2
+
+// Unsigned multiplication
+unsigned short _Accum usa_const = 1.0uhk * 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_const5 = 20.0uhk * 3.0hk;
+// CHECK-DAG: @sa_const5 = {{.*}}global i16 7680, align 2
+
+// Multiplication with negative number
+short _Accum sa_const6 = 0.5hr * (-2.0hk);
+// CHECK-DAG: @sa_const6 = {{.*}}global i16 -128, align 2
+
+// Int multiplication
+unsigned short _Accum usa_const2 = 5 * 10.5uhk;
+// CHECK-SIGNED-DAG: @usa_const2 = {{.*}}global i16 640, align 2
+// CHECK-UNSIGNED-DAG: @usa_const2 = {{.*}}global i16 320, align 2
+short _Accum sa_const7 = 3 * (-0.5hk); // CHECK-DAG: @sa_const7 = {{.*}}global i16 -192, align 2
+short _Accum sa_const8 = 100 * (-2.0hk); // CHECK-DAG: @sa_const8 = {{.*}}global i16 -25600, align 2
+long _Fract lf_const = -0.25lr * 3; // CHECK-DAG: @lf_const = {{.*}}global i32 -1610612736, align 4
+
+// Saturated multiplication
+_Sat short _Accum sat_sa_const = (_Sat short _Accum)128.0hk * 3.0hk;
+// 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 -32768, align 2
+_Sat unsigned short _Accum sat_usa_const2 = (_Sat unsigned short _Accum)128.0uhk * 30;
+// 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
+
void SignedMultiplication() {
// CHECK-LABEL: SignedMultiplication
short _Accum sa;
Index: clang/lib/Basic/FixedPoint.cpp
===================================================================
--- clang/lib/Basic/FixedPoint.cpp
+++ clang/lib/Basic/FixedPoint.cpp
@@ -197,6 +197,63 @@
return APFixedPoint(Result, CommonFXSema);
}
+APFixedPoint APFixedPoint::mul(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;
+
+ // Widen the LHS and RHS so we can perform a full multiplication.
+ unsigned Wide = CommonFXSema.getWidth() * 2;
+ if (CommonFXSema.isSigned()) {
+ ThisVal = ThisVal.sextOrSelf(Wide);
+ OtherVal = OtherVal.sextOrSelf(Wide);
+ } else {
+ ThisVal = ThisVal.zextOrSelf(Wide);
+ OtherVal = OtherVal.zextOrSelf(Wide);
+ }
+
+ // Perform the full multiplication and downscale to get the same scale.
+ //
+ // Note that the right shifts here perform an implicit downwards rounding.
+ // This rounding could discard bits that would technically place the result
+ // outside the representable range. We interpret the spec as allowing us to
+ // perform the rounding step first, avoiding the overflow case that would
+ // arise.
+ llvm::APSInt Result;
+ if (CommonFXSema.isSigned())
+ Result = ThisVal.smul_ov(OtherVal, Overflowed)
+ .ashr(CommonFXSema.getScale());
+ else
+ Result = ThisVal.umul_ov(OtherVal, Overflowed)
+ .lshr(CommonFXSema.getScale());
+ assert(!Overflowed && "Full multiplication cannot overflow!");
+ Result.setIsSigned(CommonFXSema.isSigned());
+
+ // If our result lies outside of the representative range of the common
+ // semantic, we either have overflow or saturation.
+ llvm::APSInt Max = APFixedPoint::getMax(CommonFXSema).getValue()
+ .extOrTrunc(Wide);
+ llvm::APSInt Min = APFixedPoint::getMin(CommonFXSema).getValue()
+ .extOrTrunc(Wide);
+ if (CommonFXSema.isSaturated()) {
+ if (Result < Min)
+ Result = Min;
+ else if (Result > Max)
+ Result = Max;
+ } else
+ Overflowed = Result < Min || Result > Max;
+
+ if (Overflow)
+ *Overflow = Overflowed;
+
+ return APFixedPoint(Result.sextOrTrunc(CommonFXSema.getWidth()),
+ CommonFXSema);
+}
+
void APFixedPoint::toString(llvm::SmallVectorImpl<char> &Str) const {
llvm::APSInt Val = getValue();
unsigned Scale = getScale();
Index: clang/lib/AST/ExprConstant.cpp
===================================================================
--- clang/lib/AST/ExprConstant.cpp
+++ clang/lib/AST/ExprConstant.cpp
@@ -12939,6 +12939,15 @@
return false;
return Success(Result, E);
}
+ case BO_Mul: {
+ bool AddOverflow, ConversionOverflow;
+ APFixedPoint Result = LHSFX.mul(RHSFX, &AddOverflow)
+ .convert(ResultFXSema, &ConversionOverflow);
+ if ((AddOverflow || ConversionOverflow) &&
+ !HandleOverflow(Info, E, Result, E->getType()))
+ return false;
+ return Success(Result, E);
+ }
default:
return false;
}
Index: clang/include/clang/Basic/FixedPoint.h
===================================================================
--- clang/include/clang/Basic/FixedPoint.h
+++ clang/include/clang/Basic/FixedPoint.h
@@ -129,6 +129,7 @@
// explanation of the Overflow parameter.
APFixedPoint add(const APFixedPoint &Other, bool *Overflow = nullptr) const;
APFixedPoint sub(const APFixedPoint &Other, bool *Overflow = nullptr) const;
+ APFixedPoint mul(const APFixedPoint &Other, bool *Overflow = nullptr) const;
/// Perform a unary negation (-X) on this fixed point type, taking into
/// account saturation if applicable.
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