1 //===- DemandedBitsTest.cpp - DemandedBits tests --------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/Analysis/DemandedBits.h"
10 #include "../Support/KnownBitsTest.h"
11 #include "llvm/Support/KnownBits.h"
12 #include "gtest/gtest.h"
13 
14 using namespace llvm;
15 
16 namespace {
17 
18 template <typename Fn1, typename Fn2>
19 static void TestBinOpExhaustive(Fn1 PropagateFn, Fn2 EvalFn) {
20   unsigned Bits = 4;
21   unsigned Max = 1 << Bits;
22   ForeachKnownBits(Bits, [&](const KnownBits &Known1) {
23     ForeachKnownBits(Bits, [&](const KnownBits &Known2) {
24       for (unsigned AOut_ = 0; AOut_ < Max; AOut_++) {
25         APInt AOut(Bits, AOut_);
26         APInt AB1 = PropagateFn(0, AOut, Known1, Known2);
27         APInt AB2 = PropagateFn(1, AOut, Known1, Known2);
28         {
29           // If the propagator claims that certain known bits
30           // didn't matter, check it doesn't change its mind
31           // when they become unknown.
32           KnownBits Known1Redacted;
33           KnownBits Known2Redacted;
34           Known1Redacted.Zero = Known1.Zero & AB1;
35           Known1Redacted.One = Known1.One & AB1;
36           Known2Redacted.Zero = Known2.Zero & AB2;
37           Known2Redacted.One = Known2.One & AB2;
38 
39           APInt AB1R = PropagateFn(0, AOut, Known1Redacted, Known2Redacted);
40           APInt AB2R = PropagateFn(1, AOut, Known1Redacted, Known2Redacted);
41           EXPECT_EQ(AB1, AB1R);
42           EXPECT_EQ(AB2, AB2R);
43         }
44         ForeachNumInKnownBits(Known1, [&](APInt Value1) {
45           ForeachNumInKnownBits(Known2, [&](APInt Value2) {
46             APInt ReferenceResult = EvalFn((Value1 & AB1), (Value2 & AB2));
47             APInt Result = EvalFn(Value1, Value2);
48             EXPECT_EQ(Result & AOut, ReferenceResult & AOut);
49           });
50         });
51       }
52     });
53   });
54 }
55 
56 TEST(DemandedBitsTest, Add) {
57   TestBinOpExhaustive(DemandedBits::determineLiveOperandBitsAdd,
58                       [](APInt N1, APInt N2) -> APInt { return N1 + N2; });
59 }
60 
61 TEST(DemandedBitsTest, Sub) {
62   TestBinOpExhaustive(DemandedBits::determineLiveOperandBitsSub,
63                       [](APInt N1, APInt N2) -> APInt { return N1 - N2; });
64 }
65 
66 } // anonymous namespace
67