add a few operations for signed operations that also
return an overflow flag.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116452 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/APInt.cpp b/lib/Support/APInt.cpp
index 8a212a2..51203f6 100644
--- a/lib/Support/APInt.cpp
+++ b/lib/Support/APInt.cpp
@@ -2046,6 +2046,52 @@
divide(LHS, lhsWords, RHS, rhsWords, &Quotient, &Remainder);
}
+APInt APInt::sadd_ov(const APInt &RHS, bool &Overflow) {
+ APInt Res = *this+RHS;
+ Overflow = isNonNegative() == RHS.isNonNegative() &&
+ Res.isNonNegative() != isNonNegative();
+ return Res;
+}
+
+APInt APInt::ssub_ov(const APInt &RHS, bool &Overflow) {
+ APInt Res = *this - RHS;
+ Overflow = isNonNegative() != RHS.isNonNegative() &&
+ Res.isNonNegative() != isNonNegative();
+ return Res;
+}
+
+APInt APInt::sdiv_ov(const APInt &RHS, bool &Overflow) {
+ // MININT/-1 --> overflow.
+ Overflow = isMinSignedValue() && RHS.isAllOnesValue();
+ return sdiv(RHS);
+}
+
+APInt APInt::smul_ov(const APInt &RHS, bool &Overflow) {
+ APInt Res = *this * RHS;
+
+ if (*this != 0 && RHS != 0)
+ Overflow = Res.sdiv(RHS) != *this || Res.sdiv(*this) != RHS;
+ else
+ Overflow = false;
+ return Res;
+}
+
+APInt APInt::sshl_ov(unsigned ShAmt, bool &Overflow) {
+ Overflow = ShAmt >= getBitWidth();
+ if (Overflow)
+ ShAmt = getBitWidth()-1;
+
+ if (isNonNegative()) // Don't allow sign change.
+ Overflow = ShAmt >= countLeadingZeros();
+ else
+ Overflow = ShAmt >= countLeadingOnes();
+
+ return *this << ShAmt;
+}
+
+
+
+
void APInt::fromString(unsigned numbits, StringRef str, uint8_t radix) {
// Check our assumptions here
assert(!str.empty() && "Invalid string length");