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[APInt] Make insertBits and concat work with zero width APInts.

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These should both clearly work with our current model for zero width
integers, but don't until now!

Differential Revision: https://reviews.llvm.org/D111113
This commit is contained in:
Chris Lattner 2021-10-04 21:33:51 -07:00
parent 6831c1d868
commit cc697fc292
2 changed files with 16 additions and 3 deletions
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8
llvm/lib/Support/APInt.cpp
View File

@ -345,7 +345,7 @@ void APInt::flipAllBitsSlowCase() {
/// In the slow case, we know the result is large.
APInt APInt::concatSlowCase(const APInt &NewLSB) const {
unsigned NewWidth = getBitWidth() + NewLSB.getBitWidth();
APInt Result = NewLSB.zext(NewWidth);
APInt Result = NewLSB.zextOrSelf(NewWidth);
Result.insertBits(*this, NewLSB.getBitWidth());
return Result;
}
@ -360,9 +360,13 @@ void APInt::flipBit(unsigned bitPosition) {
void APInt::insertBits(const APInt &subBits, unsigned bitPosition) {
unsigned subBitWidth = subBits.getBitWidth();
assert(0 < subBitWidth && (subBitWidth + bitPosition) <= BitWidth &&
assert(subBitWidth >= 0 && (subBitWidth + bitPosition) <= BitWidth &&
"Illegal bit insertion");
// inserting no bits is a noop.
if (subBitWidth == 0)
return;
// Insertion is a direct copy.
if (subBitWidth == BitWidth) {
*this = subBits;

11
llvm/unittests/ADT/APIntTest.cpp
View File

@ -1874,6 +1874,10 @@ TEST(APIntTest, insertBits) {
i63.insertBits(iSrc, 4);
EXPECT_EQ(static_cast<int64_t>(0x012345600123456Full), i63.getSExtValue());
// Zero width insert is a noop.
i31.insertBits(APInt::getZeroWidth(), 1);
EXPECT_EQ(static_cast<int64_t>(0x00123456ull), i31.getSExtValue());
// Insert single word src into one word of dst.
APInt i120(120, UINT64_MAX, true);
i120.insertBits(iSrc, 8);
@ -2587,7 +2591,7 @@ TEST(APIntTest, truncOrSelf) {
EXPECT_EQ(0xFFFFFFFF, val.truncOrSelf(64));
}
TEST(APIntTest, concatMSB) {
TEST(APIntTest, concat) {
APInt Int1(4, 0x1ULL);
APInt Int3(4, 0x3ULL);
@ -2597,6 +2601,11 @@ TEST(APIntTest, concatMSB) {
APInt I64(64, 0x3ULL);
EXPECT_EQ(I64, I64.concat(I64).lshr(64).trunc(64));
APInt I65(65, 0x3ULL);
APInt I0 = APInt::getZeroWidth();
EXPECT_EQ(I65, I65.concat(I0));
EXPECT_EQ(I65, I0.concat(I65));
}
TEST(APIntTest, multiply) {