From 6b943ff3a3f8617113ecbf611cf0f8957e4e19d2 Mon Sep 17 00:00:00 2001 From: Dimitry Andric Date: Mon, 2 May 2011 19:34:44 +0000 Subject: Vendor import of llvm trunk r130700: http://llvm.org/svn/llvm-project/llvm/trunk@130700 --- lib/Support/APInt.cpp | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'lib/Support/APInt.cpp') diff --git a/lib/Support/APInt.cpp b/lib/Support/APInt.cpp index 08f36d2af3a1..23a22ac68f3f 100644 --- a/lib/Support/APInt.cpp +++ b/lib/Support/APInt.cpp @@ -1517,13 +1517,15 @@ APInt::ms APInt::magic() const { /// division by a constant as a sequence of multiplies, adds and shifts. /// Requires that the divisor not be 0. Taken from "Hacker's Delight", Henry /// S. Warren, Jr., chapter 10. -APInt::mu APInt::magicu() const { +/// LeadingZeros can be used to simplify the calculation if the upper bits +/// of the divided value are known zero. +APInt::mu APInt::magicu(unsigned LeadingZeros) const { const APInt& d = *this; unsigned p; APInt nc, delta, q1, r1, q2, r2; struct mu magu; magu.a = 0; // initialize "add" indicator - APInt allOnes = APInt::getAllOnesValue(d.getBitWidth()); + APInt allOnes = APInt::getAllOnesValue(d.getBitWidth()).lshr(LeadingZeros); APInt signedMin = APInt::getSignedMinValue(d.getBitWidth()); APInt signedMax = APInt::getSignedMaxValue(d.getBitWidth()); @@ -2076,6 +2078,16 @@ APInt APInt::smul_ov(const APInt &RHS, bool &Overflow) const { return Res; } +APInt APInt::umul_ov(const APInt &RHS, bool &Overflow) const { + APInt Res = *this * RHS; + + if (*this != 0 && RHS != 0) + Overflow = Res.udiv(RHS) != *this || Res.udiv(*this) != RHS; + else + Overflow = false; + return Res; +} + APInt APInt::sshl_ov(unsigned ShAmt, bool &Overflow) const { Overflow = ShAmt >= getBitWidth(); if (Overflow) -- cgit v1.2.3