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authorSimon Pilgrim <RKSimon@users.noreply.github.com>2024-03-01 19:24:27 +0000
committerGitHub <noreply@github.com>2024-03-01 19:24:27 +0000
commitfcdf818a7779871990214cc1035bb2c36426f459 (patch)
tree2d79ccee4a2ac2ffb28564a500e580fa9a791b7b /llvm/unittests/Support/KnownBitsTest.cpp
parent1e8d3c357e1fd79bf3a641767d95147a8c0f54bd (diff)
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[KnownBits] Add KnownBits::absdiff to compute the absolute difference of 2 unsigned values (#82354)
Equivalent to "umax(A, B) - umin(A, B)" This is just an initial correctness implementation, hopefully we can make this optimal in the future.
Diffstat (limited to 'llvm/unittests/Support/KnownBitsTest.cpp')
-rw-r--r--llvm/unittests/Support/KnownBitsTest.cpp35
1 files changed, 34 insertions, 1 deletions
diff --git a/llvm/unittests/Support/KnownBitsTest.cpp b/llvm/unittests/Support/KnownBitsTest.cpp
index c0377d4..9cc5741 100644
--- a/llvm/unittests/Support/KnownBitsTest.cpp
+++ b/llvm/unittests/Support/KnownBitsTest.cpp
@@ -244,6 +244,32 @@ TEST(KnownBitsTest, SubBorrowExhaustive) {
});
}
+TEST(KnownBitsTest, AbsDiffSpecialCase) {
+ // There are 2 implementation of absdiff - both are currently needed to cover
+ // extra cases.
+ KnownBits LHS, RHS, Res;
+
+ // absdiff(LHS,RHS) = sub(umax(LHS,RHS), umin(LHS,RHS)).
+ // Actual: false (Inputs = 1011, 101?, Computed = 000?, Exact = 000?)
+ LHS.One = APInt(4, 0b1011);
+ RHS.One = APInt(4, 0b1010);
+ LHS.Zero = APInt(4, 0b0100);
+ RHS.Zero = APInt(4, 0b0100);
+ Res = KnownBits::absdiff(LHS, RHS);
+ EXPECT_EQ(0b0000, Res.One.getZExtValue());
+ EXPECT_EQ(0b1110, Res.Zero.getZExtValue());
+
+ // find the common bits between sub(LHS,RHS) and sub(RHS,LHS).
+ // Actual: false (Inputs = ???1, 1000, Computed = ???1, Exact = 0??1)
+ LHS.One = APInt(4, 0b0001);
+ RHS.One = APInt(4, 0b1000);
+ LHS.Zero = APInt(4, 0b0000);
+ RHS.Zero = APInt(4, 0b0111);
+ Res = KnownBits::absdiff(LHS, RHS);
+ EXPECT_EQ(0b0001, Res.One.getZExtValue());
+ EXPECT_EQ(0b0000, Res.Zero.getZExtValue());
+}
+
TEST(KnownBitsTest, BinaryExhaustive) {
testBinaryOpExhaustive(
[](const KnownBits &Known1, const KnownBits &Known2) {
@@ -281,7 +307,14 @@ TEST(KnownBitsTest, BinaryExhaustive) {
return KnownBits::smin(Known1, Known2);
},
[](const APInt &N1, const APInt &N2) { return APIntOps::smin(N1, N2); });
-
+ testBinaryOpExhaustive(
+ [](const KnownBits &Known1, const KnownBits &Known2) {
+ return KnownBits::absdiff(Known1, Known2);
+ },
+ [](const APInt &N1, const APInt &N2) {
+ return APIntOps::absdiff(N1, N2);
+ },
+ checkCorrectnessOnlyBinary);
testBinaryOpExhaustive(
[](const KnownBits &Known1, const KnownBits &Known2) {
return KnownBits::udiv(Known1, Known2);