From db81324c8da56cd498b58d0081b49b08095ec534 Mon Sep 17 00:00:00 2001 From: Craig Topper Date: Sun, 2 Jan 2022 23:20:32 -0800 Subject: [Support] Add KnownBits::countMaxSignedBits(). Make KnownBits::countMinSignBits() always return at least 1. Even if we don't have any known bits, we can assume that there is at least 1 sign bit. This is consistent with ComputeNumSignBits which always returns at least 1. Add KnownBits::countMaxSignedBits() which computes the number of bits needed to represent all signed values with those known bits. This is the signed equivalent of countMaxActiveBits(). Split from D116469. Reviewed By: lebedev.ri Differential Revision: https://reviews.llvm.org/D116500 --- llvm/unittests/Support/KnownBitsTest.cpp | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'llvm/unittests/Support/KnownBitsTest.cpp') diff --git a/llvm/unittests/Support/KnownBitsTest.cpp b/llvm/unittests/Support/KnownBitsTest.cpp index f9631f2..d41402b 100644 --- a/llvm/unittests/Support/KnownBitsTest.cpp +++ b/llvm/unittests/Support/KnownBitsTest.cpp @@ -442,6 +442,17 @@ TEST(KnownBitsTest, CountMaxActiveBits) { }); } +TEST(KnownBitsTest, CountMaxSignedBits) { + unsigned Bits = 4; + ForeachKnownBits(Bits, [&](const KnownBits &Known) { + unsigned Expected = 0; + ForeachNumInKnownBits(Known, [&](const APInt &N) { + Expected = std::max(Expected, N.getMinSignedBits()); + }); + EXPECT_EQ(Expected, Known.countMaxSignedBits()); + }); +} + TEST(KnownBitsTest, SExtOrTrunc) { const unsigned NarrowerSize = 4; const unsigned BaseSize = 6; -- cgit v1.1