llvm/unittests/IR/DemandedBitsTest.cpp

   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