https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111591
--- Comment #32 from Kewen Lin <linkw at gcc dot gnu.org> ---
> case pass, but the original test case (#c1) can't pass with this, it can't
> pass with -fstack-reuse=none + -fno-strict-aliasing + -O2 either, I think
> the original case still suffers another latent bug.
Well, I spent some time to narrow down the remaining issue on #c1 and found the
test case reduction generated unexpected test source (uninitialized array which
is used for assert comparison), it locates at below lines 438 to line 439:
428 struct TestSatWidenMulPairwiseAdd {
429 template <typename TN, class DN> void operator()(TN, DN dn) {
430 using TN_U = MakeUnsigned<TN>;
431 using TW = MakeWide<TN>;
432 RepartitionToWide<DN> dw;
433 using VW = Vec<decltype(dw)>;
434 using VN = Vec<decltype(dn)>;
435 size_t NN = Lanes(dn), NW = Lanes(dw), kMaxLanesPerNBlock =
sizeof(TN),
436 kMaxLanesPerWBlock = sizeof(TW);
437 RebindToUnsigned<decltype(dn)> dn_u;
438 VW f0;
439 VN nf0, nf1 = Set(dn, TN{});
440 AssertVecEqual(dw, f0, SatWidenMulPairwiseAdd(dw, BitCast(dn_u,
nf0), nf0),
441 "", 0);
The expected result is f0 while the one used for the following
SatWidenMulPairwiseAdd computation is nf0, both are not initialized.
I'd expect they are initialized, like:
VW f0 = Set(dw, TW{});
VN nf0 = Set(dn, TN{});
So IMHO #c1 test case is problematic, hi @Mathieu, could you have a double
check?
