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-rw-r--r--llvm/lib/IR/ConstantFPRange.cpp166
1 files changed, 166 insertions, 0 deletions
diff --git a/llvm/lib/IR/ConstantFPRange.cpp b/llvm/lib/IR/ConstantFPRange.cpp
index 51d2e21..5b87686 100644
--- a/llvm/lib/IR/ConstantFPRange.cpp
+++ b/llvm/lib/IR/ConstantFPRange.cpp
@@ -8,6 +8,7 @@
#include "llvm/IR/ConstantFPRange.h"
#include "llvm/ADT/APFloat.h"
+#include "llvm/ADT/FloatingPointMode.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
@@ -506,3 +507,168 @@ ConstantFPRange ConstantFPRange::sub(const ConstantFPRange &Other) const {
// fsub X, Y = fadd X, (fneg Y)
return add(Other.negate());
}
+
+void ConstantFPRange::flushDenormals(DenormalMode::DenormalModeKind Mode) {
+ if (Mode == DenormalMode::IEEE)
+ return;
+ FPClassTest Class = classify();
+ if (!(Class & fcSubnormal))
+ return;
+
+ auto &Sem = getSemantics();
+ // PreserveSign: PosSubnormal -> PosZero, NegSubnormal -> NegZero
+ // PositiveZero: PosSubnormal -> PosZero, NegSubnormal -> PosZero
+ // Dynamic: PosSubnormal -> PosZero, NegSubnormal -> NegZero/PosZero
+ bool ZeroLowerNegative =
+ Mode != DenormalMode::PositiveZero && (Class & fcNegSubnormal);
+ bool ZeroUpperNegative =
+ Mode == DenormalMode::PreserveSign && !(Class & fcPosSubnormal);
+ assert((ZeroLowerNegative || !ZeroUpperNegative) &&
+ "ZeroLower is greater than ZeroUpper.");
+ Lower = minnum(Lower, APFloat::getZero(Sem, ZeroLowerNegative));
+ Upper = maxnum(Upper, APFloat::getZero(Sem, ZeroUpperNegative));
+}
+
+/// Represent a contiguous range of values sharing the same sign.
+struct SameSignRange {
+ bool HasZero;
+ bool HasNonZero;
+ bool HasInf;
+ // The lower and upper bounds of the range (inclusive).
+ // The sign is dropped and infinities are excluded.
+ std::optional<std::pair<APFloat, APFloat>> FinitePart;
+
+ explicit SameSignRange(const APFloat &Lower, const APFloat &Upper)
+ : HasZero(Lower.isZero()), HasNonZero(!Upper.isZero()),
+ HasInf(Upper.isInfinity()) {
+ assert(!Lower.isNegative() && !Upper.isNegative() &&
+ "The sign should be dropped.");
+ assert(strictCompare(Lower, Upper) != APFloat::cmpGreaterThan &&
+ "Empty set.");
+ if (!Lower.isInfinity())
+ FinitePart = {Lower,
+ HasInf ? APFloat::getLargest(Lower.getSemantics()) : Upper};
+ }
+};
+
+/// Split the range into positive and negative components.
+static void splitPosNeg(const APFloat &Lower, const APFloat &Upper,
+ std::optional<SameSignRange> &NegPart,
+ std::optional<SameSignRange> &PosPart) {
+ assert(strictCompare(Lower, Upper) != APFloat::cmpGreaterThan &&
+ "Non-NaN part is empty.");
+ if (Lower.isNegative() == Upper.isNegative()) {
+ if (Lower.isNegative())
+ NegPart = SameSignRange{abs(Upper), abs(Lower)};
+ else
+ PosPart = SameSignRange{Lower, Upper};
+ return;
+ }
+ auto &Sem = Lower.getSemantics();
+ NegPart = SameSignRange{APFloat::getZero(Sem), abs(Lower)};
+ PosPart = SameSignRange{APFloat::getZero(Sem), Upper};
+}
+
+ConstantFPRange ConstantFPRange::mul(const ConstantFPRange &Other) const {
+ auto &Sem = getSemantics();
+ bool ResMayBeQNaN = ((MayBeQNaN || MayBeSNaN) && !Other.isEmptySet()) ||
+ ((Other.MayBeQNaN || Other.MayBeSNaN) && !isEmptySet());
+ if (isNaNOnly() || Other.isNaNOnly())
+ return getNaNOnly(Sem, /*MayBeQNaN=*/ResMayBeQNaN,
+ /*MayBeSNaN=*/false);
+ std::optional<SameSignRange> LHSNeg, LHSPos, RHSNeg, RHSPos;
+ splitPosNeg(Lower, Upper, LHSNeg, LHSPos);
+ splitPosNeg(Other.Lower, Other.Upper, RHSNeg, RHSPos);
+ APFloat ResLower = APFloat::getInf(Sem, /*Negative=*/false);
+ APFloat ResUpper = APFloat::getInf(Sem, /*Negative=*/true);
+ auto Update = [&](std::optional<SameSignRange> &LHS,
+ std::optional<SameSignRange> &RHS, bool Negative) {
+ if (!LHS || !RHS)
+ return;
+ // 0 * inf = QNaN
+ ResMayBeQNaN |= LHS->HasZero && RHS->HasInf;
+ ResMayBeQNaN |= RHS->HasZero && LHS->HasInf;
+ // NonZero * inf = inf
+ if ((LHS->HasInf && RHS->HasNonZero) || (RHS->HasInf && LHS->HasNonZero))
+ (Negative ? ResLower : ResUpper) = APFloat::getInf(Sem, Negative);
+ // Finite * Finite
+ if (LHS->FinitePart && RHS->FinitePart) {
+ APFloat NewLower = LHS->FinitePart->first * RHS->FinitePart->first;
+ APFloat NewUpper = LHS->FinitePart->second * RHS->FinitePart->second;
+ if (Negative) {
+ ResLower = minnum(ResLower, -NewUpper);
+ ResUpper = maxnum(ResUpper, -NewLower);
+ } else {
+ ResLower = minnum(ResLower, NewLower);
+ ResUpper = maxnum(ResUpper, NewUpper);
+ }
+ }
+ };
+ Update(LHSNeg, RHSNeg, /*Negative=*/false);
+ Update(LHSNeg, RHSPos, /*Negative=*/true);
+ Update(LHSPos, RHSNeg, /*Negative=*/true);
+ Update(LHSPos, RHSPos, /*Negative=*/false);
+ return ConstantFPRange(ResLower, ResUpper, ResMayBeQNaN, /*MayBeSNaN=*/false);
+}
+
+ConstantFPRange ConstantFPRange::div(const ConstantFPRange &Other) const {
+ auto &Sem = getSemantics();
+ bool ResMayBeQNaN = ((MayBeQNaN || MayBeSNaN) && !Other.isEmptySet()) ||
+ ((Other.MayBeQNaN || Other.MayBeSNaN) && !isEmptySet());
+ if (isNaNOnly() || Other.isNaNOnly())
+ return getNaNOnly(Sem, /*MayBeQNaN=*/ResMayBeQNaN,
+ /*MayBeSNaN=*/false);
+ std::optional<SameSignRange> LHSNeg, LHSPos, RHSNeg, RHSPos;
+ splitPosNeg(Lower, Upper, LHSNeg, LHSPos);
+ splitPosNeg(Other.Lower, Other.Upper, RHSNeg, RHSPos);
+ APFloat ResLower = APFloat::getInf(Sem, /*Negative=*/false);
+ APFloat ResUpper = APFloat::getInf(Sem, /*Negative=*/true);
+ auto Update = [&](std::optional<SameSignRange> &LHS,
+ std::optional<SameSignRange> &RHS, bool Negative) {
+ if (!LHS || !RHS)
+ return;
+ // inf / inf = QNaN 0 / 0 = QNaN
+ ResMayBeQNaN |= LHS->HasInf && RHS->HasInf;
+ ResMayBeQNaN |= LHS->HasZero && RHS->HasZero;
+ // It is not straightforward to infer HasNonZeroFinite = HasFinite &&
+ // HasNonZero. By definitions we have:
+ // HasFinite = HasNonZeroFinite || HasZero
+ // HasNonZero = HasNonZeroFinite || HasInf
+ // Since the range is contiguous, if both HasFinite and HasNonZero are true,
+ // HasNonZeroFinite must be true.
+ bool LHSHasNonZeroFinite = LHS->FinitePart && LHS->HasNonZero;
+ bool RHSHasNonZeroFinite = RHS->FinitePart && RHS->HasNonZero;
+ // inf / Finite = inf FiniteNonZero / 0 = inf
+ if ((LHS->HasInf && RHS->FinitePart) ||
+ (LHSHasNonZeroFinite && RHS->HasZero))
+ (Negative ? ResLower : ResUpper) = APFloat::getInf(Sem, Negative);
+ // Finite / inf = 0
+ if (LHS->FinitePart && RHS->HasInf) {
+ APFloat Zero = APFloat::getZero(Sem, /*Negative=*/Negative);
+ ResLower = minnum(ResLower, Zero);
+ ResUpper = maxnum(ResUpper, Zero);
+ }
+ // Finite / FiniteNonZero
+ if (LHS->FinitePart && RHSHasNonZeroFinite) {
+ assert(!RHS->FinitePart->second.isZero() &&
+ "Divisor should be non-zero.");
+ APFloat NewLower = LHS->FinitePart->first / RHS->FinitePart->second;
+ APFloat NewUpper = LHS->FinitePart->second /
+ (RHS->FinitePart->first.isZero()
+ ? APFloat::getSmallest(Sem, /*Negative=*/false)
+ : RHS->FinitePart->first);
+ if (Negative) {
+ ResLower = minnum(ResLower, -NewUpper);
+ ResUpper = maxnum(ResUpper, -NewLower);
+ } else {
+ ResLower = minnum(ResLower, NewLower);
+ ResUpper = maxnum(ResUpper, NewUpper);
+ }
+ }
+ };
+ Update(LHSNeg, RHSNeg, /*Negative=*/false);
+ Update(LHSNeg, RHSPos, /*Negative=*/true);
+ Update(LHSPos, RHSNeg, /*Negative=*/true);
+ Update(LHSPos, RHSPos, /*Negative=*/false);
+ return ConstantFPRange(ResLower, ResUpper, ResMayBeQNaN, /*MayBeSNaN=*/false);
+}
generated by cgit v1.1 at 2025-10-13 23:43:51 +0000