We will insert a new operand which is identical to the Dest for complex
FMUL with a mask. https://godbolt.org/z/eTEdnYv3q
Complex FMA and FMUL with maskz don't have this problem.
Reviewed By: LuoYuanke, skan
Differential Revision: https://reviews.llvm.org/D130638
Summary:
Introduce NeverAlign fragment type.
The intended usage of this fragment is to insert it before a pair of
macro-op fusion eligible instructions. NeverAlign fragment ensures that
the next fragment (first instruction in the pair) does not end at a
given alignment boundary by emitting a minimal size nop if necessary.
In effect, it ensures that a pair of macro-fusible instructions is not
split by a given alignment boundary, which is a precondition for
macro-op fusion in modern Intel Cores (64B = cache line size, see Intel
Architecture Optimization Reference Manual, 2.3.2.1 Legacy Decode
Pipeline: Macro-Fusion).
This patch introduces functionality used by BOLT when emitting code with
MacroFusion alignment already in place.
The use case is different from BoundaryAlign and instruction bundling:
- BoundaryAlign can be extended to perform the desired alignment for the
first instruction in the macro-op fusion pair (D101817). However, this
approach has higher overhead due to reliance on relaxation as
BoundaryAlign requires in the general case - see
https://reviews.llvm.org/D97982#2710638.
- Instruction bundling: the intent of NeverAlign fragment is to prevent
the first instruction in a pair ending at a given alignment boundary, by
inserting at most one minimum size nop. It's OK if either instruction
crosses the cache line. Padding both instructions using bundles to not
cross the alignment boundary would result in excessive padding. There's
no straightforward way to request instruction bundling to avoid a given
end alignment for the first instruction in the bundle.
LLVM: https://reviews.llvm.org/D97982
Manual rebase conflict history:
https://phabricator.intern.facebook.com/D30142613
Test Plan: sandcastle
Reviewers: #llvm-bolt
Subscribers: phabricatorlinter
Differential Revision: https://phabricator.intern.facebook.com/D31361547
Add support for the RDPRU instruction on Zen2 processors.
User-facing features:
- Clang option -m[no-]rdpru to enable/disable the feature
- Support is implicit for znver2/znver3 processors
- Preprocessor symbol __RDPRU__ to indicate support
- Header rdpruintrin.h to define intrinsics
- "rdpru" mnemonic supported for assembler code
Internal features:
- Clang builtin __builtin_ia32_rdpru
- IR intrinsic @llvm.x86.rdpru
Differential Revision: https://reviews.llvm.org/D128934
This resolves problems reported in commit 1a20252978.
1. Promote to float lowering for nodes XINT_TO_FP
2. Bail out f16 from shuffle combine due to vector type is not legal in the version
Previously, omitting unnecessary DWARF unwinds was only done in two
cases:
* For Darwin + aarch64, if no DWARF unwind info is needed for all the
functions in a TU, then the `__eh_frame` section would be omitted
entirely. If any one function needed DWARF unwind, then MC would emit
DWARF unwind entries for all the functions in the TU.
* For watchOS, MC would omit DWARF unwind on a per-function basis, as
long as compact unwind was available for that function.
This diff makes it so that we omit DWARF unwind on a per-function basis
for Darwin + aarch64 as well. In addition, we introduce the flag
`--emit-dwarf-unwind=` which can toggle between `always`,
`no-compact-unwind` (only emit DWARF when CU cannot be emitted for a
given function), and the target platform `default`. `no-compact-unwind`
is particularly useful for newer x86_64 platforms: we don't want to omit
DWARF unwind for x86_64 in general due to possible backwards compat
issues, but we should make it possible for people to opt into this
behavior if they are only targeting newer platforms.
**Motivation:** I'm working on adding support for `__eh_frame` to LLD,
but I'm concerned that we would suffer a perf hit. Processing compact
unwind is already expensive, and that's a simpler format than EH frames.
Given that MC currently produces one EH frame entry for every compact
unwind entry, I don't think processing them will be cheap. I tried to do
something clever on LLD's end to drop the unnecessary EH frames at parse
time, but this made the code significantly more complex. So I'm looking
at fixing this at the MC level instead.
**Addendum:** It turns out that there was a latent bug in the X86
backend when `OmitDwarfIfHaveCompactUnwind` is naively enabled, which is
not too surprising given that this combination has not been heretofore
used.
For functions that have unwind info that cannot be encoded with CU, MC
would end up dropping both the compact unwind entry (OK; existing
behavior) as well as the DWARF entries (not OK). This diff fixes things
so that we emit the DWARF entry, as well as a CU entry with encoding
`UNWIND_X86_MODE_DWARF` -- this basically tells the unwinder to look for
the DWARF entry. I'm not 100% sure the `UNWIND_X86_MODE_DWARF` CU entry
is necessary, this was the simplest fix. ld64 seems to be able to handle
both the absence and presence of this CU entry. Ultimately ld64 (and
LLD) will synthesize `UNWIND_X86_MODE_DWARF` if it is absent, so there
is no impact to the final binary size.
Reviewed By: davide, lhames
Differential Revision: https://reviews.llvm.org/D122258
GCC and Clang/LLVM will support `_Float16` on X86 in C/C++, following
the latest X86 psABI. (https://gitlab.com/x86-psABIs)
_Float16 arithmetic will be performed using native half-precision. If
native arithmetic instructions are not available, it will be performed
at a higher precision (currently always float) and then truncated down
to _Float16 immediately after each single arithmetic operation.
Reviewed By: LuoYuanke
Differential Revision: https://reviews.llvm.org/D107082
These two tests were intended to cover the CU code paths, but invoked
llvm-mc using a generic "darwin" platform. However, MC only attempts to
emit CU for `macos >= 10.6` [1]. Thus we adjust the tests accordingly.
compact-unwind-cfi_def_cfa.s was added in 2fca51d3b4
fp-setup-macho.s was added in 03ffa797ad
[1]: 16c93aaa4a/llvm/lib/MC/MCObjectFileInfo.cpp (L43)
Reviewed By: MaskRay, smeenai
Differential Revision: https://reviews.llvm.org/D124126
Fix prefix emission order to emit REX immediately before the opcode (SDM vol2,
2.1, Figure 2-1). According to SDM vol2 2.2.1, "Other placements are ignored".
This fix has a side effect of outputting segment override prefix in a different
order than previously (benign).
Follow-up to https://reviews.llvm.org/D120592
Reviewed By: skan, craig.topper
Differential Revision: https://reviews.llvm.org/D120871
Print and emit redundant Address-Size override prefix if it's set on the
instruction.
Reviewed By: skan
Differential Revision: https://reviews.llvm.org/D120592
For tagged-globals, we only need to disable relaxation for globals that
we actually tag. With this patch function pointer relocations, which
we do not instrument, can be relaxed.
This patch also makes tagged-globals work properly with LTO, as
-Wa,-mrelax-relocations=no doesn't work with LTO.
Reviewed By: pcc
Differential Revision: https://reviews.llvm.org/D113220
Commit 8fa3e8fa14 added an implicit REP prefix to all VIA PadLock
instructions, but GNU as doesn't add one to xstore, only all the others.
This resulted in a kernel panic regression in FreeBSD upon updating to
LLVM 11 (https://bugs.freebsd.org/259218) which includes the commit in
question. This partially reverts that commit.
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D112355
We currently only test the encoding of xstore but none of the other
instructions, which should all have their implicit REP prefix be
verified as working.
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D112354
GCC 9.1 removed Intel MPX support. Linux kernel removed MPX in 2019.
glibc 2.35 will remove MPX.
Our support is limited: we support assembling of bndmov but not bnd.
Just remove it.
Reviewed By: pengfei, skan
Differential Revision: https://reviews.llvm.org/D111517
This enables printing of the mnemonics that contain the predicate
in the Intel printer. This requires accounting for the memory size
that is explicitly printed in Intel syntax. Those changes have been
synced to the ATT printer as well.
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D108093
The maskmovdqu instruction is an odd one: it has a 32-bit and a 64-bit
variant, the former using EDI, the latter RDI, but the use of the
register is implicit. In 64-bit mode, a 0x67 prefix can be used to get
the version using EDI, but there is no way to express this in
assembly in a single instruction, the only way is with an explicit
addr32.
This change adds support for the instruction. When generating assembly
text, that explicit addr32 will be added. When not generating assembly
text, it will be kept as a single instruction and will be emitted with
that 0x67 prefix. When parsing assembly text, it will be re-parsed as
ADDR32 followed by MASKMOVDQU64, which still results in the correct
bytes when converted to machine code.
The same applies to vmaskmovdqu as well.
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D103427
This patch adds a test case showing how a single extra .loc can cause
binary differences when using -x86-pad-for-align=true.
The issue has been discussed in D94542, PR42138, PR48742.
Did not correctly handle "jecxz short <address>".
Discovered while working on LLVM-ML; shows up in z_Windows_NT-586_asm.asm from the OpenMP runtime
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D104194
In 16-bit mode, some of the nop patterns used in 32-bit mode can end up
mangling other instructions. For instance, an aligned "movz" instruction
may have the 0x66 and 0x67 prefixes omitted, because the nop that's used
messes things up.
xorl %ebx, %ebx
.p2align 4, 0x90
movzbl (%esi,%ebx), %ecx
Use instead nop patterns we know 16-bit mode can handle.
Differential Revision: https://reviews.llvm.org/D97268
This is consistent with the VEX version. It also fixes a sorting
issue in the matching table that caused the EVEX version to be
prioritized over VEX in intel syntax.
Fixes issue [2] from PR48991.
X86 allows for the "addr32" and "addr16" address size override prefixes.
Also, these and the segment override prefixes should be recognized as
valid prefixes.
Differential Revision: https://reviews.llvm.org/D94726
Fix PR48742: the D75203 assembler optimization locates MCRelaxableFragment's
within two MCSymbol's and relaxes some MCRelaxableFragment's to reduce the size
of a MCAlignFragment. A -g build has more MCSymbol's and therefore may have
different assembler output (e.g. a MCRelaxableFragment (jmp) may have 5 bytes
with -O1 while 2 bytes with -O1 -g).
`.p2align 4, 0x90` is common due to loops. For a larger program, with a
lot of temporary labels, the assembly output difference is somewhat
destined. The cost seems to overweigh the benefits so we default to
-x86-pad-for-align=false until the heuristic is improved.
Reviewed By: skan
Differential Revision: https://reviews.llvm.org/D94542
Phoebe Wang