SuccessChanges

Summary

  1. [lld/mac] Propagate -(un)exported_symbol(s_list) to privateExtern in Driver (details)
  2. [X86][AVX] Cleanup AVX2 vector integer truncation costs (details)
  3. [LLD] [MinGW] Pass the canExitEarly parameter through properly (details)
  4. [NFC] Removed unused VFInfo comparison operator (details)
  5. [libcxx][test] Attempt to make debug mode tests more bulletproof (details)
  6. [X86] AMD Zen 3: cap LoopMicroOpBufferSize to workaround PR50384 (quadratic IndVars runtime) (details)
Commit 095c520fb436103c9800de0ac15fed83a86f3a43 by thakis
[lld/mac] Propagate -(un)exported_symbol(s_list) to privateExtern in Driver

That way, it's done only once instead of every time shouldExportSymbol() is
called.

Possibly a bit faster:

    % ministat at_main at_symtodo
    x at_main
    + at_symtodo
        N           Min           Max        Median           Avg        Stddev
    x  30     3.9732189      4.114846      4.024621     4.0304692   0.037022865
    +  30       3.93766     4.0510042     3.9973931      3.991469   0.028472565
    Difference at 95.0% confidence
            -0.0390002 +/- 0.0170714
            -0.967635% +/- 0.423559%
            (Student's t, pooled s = 0.0330256)

In other runs with n=30 it makes no perf difference, so maybe it's just noise.
But being able to quickly and conveniently answer "is this symbol exported?"
is useful for fixing PR50373 and for implementing -dead_strip, so this seems
like a good change regardless.

No behavior change.

Differential Revision: https://reviews.llvm.org/D102661
The file was modifiedlld/MachO/SyntheticSections.cpp
The file was modifiedlld/MachO/Driver.cpp
Commit 560b709abedc76d7944be38d2f38b7bc8d40e32d by llvm-dev
[X86][AVX] Cleanup AVX2 vector integer truncation costs

Noticed while investigating PR50364, the truncation costs for v4i64->v4i16/v4i8 and v8i32->v8i8 were way too optimistic for a shuffle sequence that usually matches the AVX1 codegen (they matched AVX512 numbers which have actual truncation instructions!).
The file was modifiedllvm/test/Analysis/CostModel/X86/trunc.ll
The file was modifiedllvm/test/Analysis/CostModel/X86/cast.ll
The file was modifiedllvm/lib/Target/X86/X86TargetTransformInfo.cpp
Commit dd7575ba44f0e255e3d3c04bc60648a8d41a18d4 by martin
[LLD] [MinGW] Pass the canExitEarly parameter through properly

The MinGW driver passed a hardcoded true to this parameter
since 6f4e255219f2a7878d3, but when the MinGW driver got the
canExitEarly parameter for consistency in b11386f9be9b2dc7276, this
call was missed so it wasn't passed on properly.
The file was modifiedlld/MinGW/Driver.cpp
Commit 38e2359a11e9be500b38245737e47324d54fe0b4 by david.sherwood
[NFC] Removed unused VFInfo comparison operator
The file was modifiedllvm/include/llvm/Analysis/VectorUtils.h
Commit 9f4f012c10266c2117f80b7c7eb699aadef0589d by kbessonova
[libcxx][test] Attempt to make debug mode tests more bulletproof

The problem with debug mode tests is that it isn't known which particular
_LIBCPP_ASSERT causes the test to exit, and as shown by
https://reviews.llvm.org/D100029 and 2908eb20ba7 it might be not the
expected one.

The patch adds TEST_LIBCPP_ASSERT_FAILURE macro that allows checking
_LIBCPP_ASSERT message to ensure we caught an expected failure.

Reviewed By: Quuxplusone, ldionne

Differential Revision: https://reviews.llvm.org/D100595
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_cfront.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/db_insert_hint_const_lvalue.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/front.const.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.modifiers/erase_iter_iter_db7.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_iterators_12.pass.cpp
The file was modifiedlibcxx/test/libcxx/utilities/optional/optional.object/optional.object.observe/dereference_rvalue.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/db_index.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.modifiers/erase_iter_db3.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_iterators_9.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.modifiers/erase_iter_iter_db2.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.iterators/db_iterators_14.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_cback.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/db_cindex_2.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/db_local_iterators_8.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_iterators_4.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/db_cback.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.iterators/db_iterators_11.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/bucket_size.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/db_iterators_10.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/db_local_iterators_7.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/max_load_factor.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/bucket_size.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/db_iterators_9.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_iterators_10.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_iterators_2.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/db_iterators_8.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/unord.map.modifiers/erase_iter_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/pop_back_empty.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/db_insert_hint_const_lvalue.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/bucket.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.iterators/db_iterators_4.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_value_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/list/list.modifiers/emplace_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/db_local_iterators_10.pass.cpp
The file was modifiedlibcxx/test/libcxx/utilities/optional/optional.object/optional.object.observe/op_arrow.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/list/list.cons/db_copy.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/db_local_iterators_7.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/db_local_iterators_7.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/db_cfront_2.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/db_local_iterators_9.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_cback_2.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.modifiers/erase_iter_iter_db3.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.modifiers/erase_iter_iter_db8.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_iterators_14.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/db_iterators_8.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/db_local_iterators_7.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/index.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/db_insert_hint_rvalue.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.iterators/db_iterators_10.pass.cpp
The file was modifiedlibcxx/test/libcxx/utilities/optional/optional.object/optional.object.observe/dereference_const_rvalue.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db4.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/db_iterators_7.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/db_iterators_9.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/erase_iter_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_db2.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/db_cindex.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.modifiers/insert_iter_char_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.modifiers/erase_iter_iter_db6.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_size_value_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_rvalue_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/utilities/optional/optional.object/optional.object.observe/op_arrow_const.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/bucket.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/erase_iter_iter_db2.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_iterators_11.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/max_load_factor.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/list/list.ops/db_splice_pos_list_iter.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.iterators/db_iterators_2.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/list/list.modifiers/pop_back_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/db_swap_1.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.iterators/db_iterators_7.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.modifiers/insert_iter_iter_iter_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_db2.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_front_2.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/erase_iter_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/db_back.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.iterators/db_iterators_12.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/db_local_iterators_8.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/db_bucket.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db2.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/bucket_size.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.modifiers/erase_pop_back_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/erase_iter_iter_db3.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/db_index_2.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/db_iterators_9.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/db_local_iterators_9.pass.cpp
The file was modifiedlibcxx/test/libcxx/utilities/optional/optional.object/optional.object.observe/dereference.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_cindex.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/db_swap_1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_iterators_8.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_iter_iter_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/unord.map.modifiers/erase_iter_db2.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_index.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/erase_iter_iter_db4.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/erase_iter_iter_db3.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/db_local_iterators_10.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_index_2.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db2.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_iterators_3.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/db_front_2.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/erase_iter_iter_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/db_front.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.iterators/db_iterators_13.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/erase_iter_iter_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/db_iterators_10.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/back.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_back.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/erase_iter_iter_db4.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/db_iterators_8.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/erase_iter_iter_db2.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.iterators/db_iterators_6.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/db_iterators_7.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/db_back_2.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/front.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.modifiers/erase_iter_iter_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_iterators_13.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/deque/pop_back_empty.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/max_load_factor.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_cindex_2.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/db_local_iterators_9.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.iterators/db_iterators_5.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/db_cback_2.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/index.const.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/db_iterators_7.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db4.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.modifiers/erase_iter_db4.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db3.pass.cpp
The file was addedlibcxx/test/support/debug_macros.h
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.modifiers/erase_iter_iter_db4.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_cfront_2.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.iterators/db_iterators_8.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_iterators_15.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db2.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/db_iterators_7.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.iterators/db_iterators_9.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/db_iterators_10.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/bucket.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_iterators_7.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/erase_iter_db2.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/back.const.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/db_insert_hint_rvalue.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/db_iterators_9.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.modifiers/erase_iter_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/db_swap_1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.iterators/db_iterators_15.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_iterators_6.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.modifiers/insert_iter_size_char_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/db_swap_1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/db_local_iterators_10.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_front.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/db_local_iterators_10.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/db_local_iterators_9.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.iterators/db_iterators_3.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/bucket_size.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/db_local_iterators_8.pass.cpp
The file was modifiedlibcxx/test/libcxx/utilities/optional/optional.object/optional.object.observe/dereference_const.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/unord.multimap.modifiers/erase_iter_iter_db3.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/list/list.ops/db_splice_pos_list.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/max_load_factor.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db4.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_iterators_5.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.map/unord.map.modifiers/erase_iter_iter_db1.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/db_iterators_10.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/db_iterators_8.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multimap/db_insert_hint_const_lvalue.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.modifiers/erase_iter_iter_db5.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db3.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/db_insert_hint_const_lvalue.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/vector/db_back_2.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/sequences/list/list.ops/db_splice_pos_list_iter_iter.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.access/db_cfront.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.multiset/db_local_iterators_8.pass.cpp
The file was modifiedlibcxx/test/libcxx/containers/unord/unord.set/erase_iter_db2.pass.cpp
The file was modifiedlibcxx/test/libcxx/strings/basic.string/string.modifiers/erase_iter_db2.pass.cpp
Commit 3cc39607668d6f942458a37e7a9111294d9373bd by lebedev.ri
[X86] AMD Zen 3: cap LoopMicroOpBufferSize to workaround PR50384 (quadratic IndVars runtime)

While i would like to keep the right value here,
i would also like to be able to actually compile
e.g. vanilla test-suite.

256 is a pretty random guess, it should be pretty good enough
for serious loops, but small enough to result in tolerant
compile times for certain edge cases.

https://bugs.llvm.org/show_bug.cgi?id=50384
The file was modifiedllvm/lib/Target/X86/X86ScheduleZnver3.td