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From: "linkw at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/111591] ppc64be: miscompilation with -mstrict-align / -O3
Date: Tue, 31 Oct 2023 06:40:29 +0000	[thread overview]
Message-ID: <bug-111591-4-W8jsuyZBGT@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-111591-4@http.gcc.gnu.org/bugzilla/>

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?

  parent reply	other threads:[~2023-10-31  6:40 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-25 11:53 [Bug target/111591] New: " malat at debian dot org
2023-09-25 11:55 ` [Bug target/111591] " malat at debian dot org
2023-09-25 11:59 ` rguenth at gcc dot gnu.org
2023-09-25 12:20 ` malat at debian dot org
2023-09-25 13:15 ` malat at debian dot org
2023-09-25 13:41 ` malat at debian dot org
2023-09-26  6:50 ` linkw at gcc dot gnu.org
2023-09-26  7:56 ` rguenth at gcc dot gnu.org
2023-09-26  8:14 ` linkw at gcc dot gnu.org
2023-09-26  9:28 ` malat at debian dot org
2023-09-26  9:28 ` malat at debian dot org
2023-09-26  9:31 ` malat at debian dot org
2023-09-26  9:31 ` malat at debian dot org
2023-09-27  9:24 ` linkw at gcc dot gnu.org
2023-09-27  9:26 ` rguenth at gcc dot gnu.org
2023-09-28  0:20 ` linkw at gcc dot gnu.org
2023-10-13 10:19 ` linkw at gcc dot gnu.org
2023-10-13 11:08 ` rguenth at gcc dot gnu.org
2023-10-13 12:09 ` linkw at gcc dot gnu.org
2023-10-13 12:32 ` rguenth at gcc dot gnu.org
2023-10-16  9:11 ` linkw at gcc dot gnu.org
2023-10-19  7:27 ` linkw at gcc dot gnu.org
2023-10-19 11:06 ` rguenth at gcc dot gnu.org
2023-10-19 11:12 ` rguenth at gcc dot gnu.org
2023-10-20  5:53 ` linkw at gcc dot gnu.org
2023-10-20  6:25 ` rguenth at gcc dot gnu.org
2023-10-23  3:21 ` linkw at gcc dot gnu.org
2023-10-23  9:48 ` rguenth at gcc dot gnu.org
2023-10-23 12:36 ` matz at gcc dot gnu.org
2023-10-23 13:30 ` rguenth at gcc dot gnu.org
2023-10-23 14:04 ` rguenth at gcc dot gnu.org
2023-10-24  2:59 ` linkw at gcc dot gnu.org
2023-10-31  6:40 ` linkw at gcc dot gnu.org [this message]
2023-12-13  8:00 ` cvs-commit at gcc dot gnu.org
2023-12-13  8:02 ` rguenth at gcc dot gnu.org
2023-12-13  8:12 ` rguenth at gcc dot gnu.org
2023-12-15  7:32 ` malat at debian dot org
2023-12-15  7:43 ` rguenth at gcc dot gnu.org
2023-12-15 10:01 ` linkw at gcc dot gnu.org
2023-12-15 10:23 ` rguenth at gcc dot gnu.org
2023-12-15 11:28 ` malat at debian dot org
2023-12-15 11:32 ` rguenth at gcc dot gnu.org
2023-12-18  6:01 ` linkw at gcc dot gnu.org
2023-12-18  6:03 ` linkw at gcc dot gnu.org
2023-12-19  5:38 ` linkw at gcc dot gnu.org

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