Summary:
Add a target option AllowRegisterRenaming that is used to opt in to
post-register-allocation renaming of registers. This is set to 0 by
default, which causes the hasExtraSrcRegAllocReq/hasExtraDstRegAllocReq
fields of all opcodes to be set to 1, causing
MachineOperand::isRenamable to always return false.
Set the AllowRegisterRenaming flag to 1 for all in-tree targets that
have lit tests that were effected by enabling COPY forwarding in
MachineCopyPropagation (AArch64, AMDGPU, ARM, Hexagon, Mips, PowerPC,
RISCV, Sparc, SystemZ and X86).
Add some more comments describing the semantics of the
MachineOperand::isRenamable function and how it is set and maintained.
Change isRenamable to check the operand's opcode
hasExtraSrcRegAllocReq/hasExtraDstRegAllocReq bit directly instead of
relying on it being consistently reflected in the IsRenamable bit
setting.
Clear the IsRenamable bit when changing an operand's register value.
Remove target code that was clearing the IsRenamable bit when changing
registers/opcodes now that this is done conservatively by default.
Change setting of hasExtraSrcRegAllocReq in AMDGPU target to be done in
one place covering all opcodes that have constant pipe read limit
restrictions.
Reviewers: qcolombet, MatzeB
Subscribers: aemerson, arsenm, jyknight, mcrosier, sdardis, nhaehnle, javed.absar, tpr, arichardson, kristof.beyls, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, jordy.potman.lists, apazos, sabuasal, niosHD, escha, nemanjai, llvm-commits
Differential Revision: https://reviews.llvm.org/D43042
llvm-svn: 325931
Summary:
There are transformation that change setcc into other constructs, and transform that try to reconstruct a setcc from the brcond condition. Depending on what order these transform are done, the end result differs.
Most of the time, it is preferable to get a setcc as a brcond argument (and this is why brcond try to recreate the setcc in the first place) so we ensure this is done every time by also doing it at the setcc level when the only user is a brcond.
Reviewers: spatel, hfinkel, niravd, craig.topper
Subscribers: nhaehnle, llvm-commits
Differential Revision: https://reviews.llvm.org/D41235
llvm-svn: 325892
Add GlobalISel infrastructure up to the point where we can select a ret
void.
Patch by Petar Avramovic.
Differential Revision: https://reviews.llvm.org/D43583
llvm-svn: 325888
Summary:
This handles def-after-use of physregs, and allows us to merge loads and
stores even across some physreg defs (typically M0 defs).
Change-Id: I076484b2bda27c2cf46013c845a0380c5b89b67b
Reviewers: arsenm, mareko, rampitec
Subscribers: kzhuravl, wdng, yaxunl, dstuttard, tpr, t-tye, llvm-commits
Differential Revision: https://reviews.llvm.org/D42647
llvm-svn: 325882
Summary:
This fixes cases like the new test @nonuniform. In that test, %cc itself
is a uniform value; however, when reading it after the end of the loop in
basic block %if, its value is effectively non-uniform.
This problem was encountered in
https://bugs.freedesktop.org/show_bug.cgi?id=103743; however, this change
in itself is not sufficient to fix that bug, as there is another issue
in the AMDGPU backend.
Change-Id: I32bbffece4a32f686fab54964dae1a5dd72949d4
Reviewers: arsenm, rampitec, jlebar
Subscribers: wdng, tpr, llvm-commits
Differential Revision: https://reviews.llvm.org/D40546
llvm-svn: 325881
Enable multiple COPY hints to eliminate more COPYs during register allocation.
Note that this is something all targets should do, see
https://reviews.llvm.org/D38128.
Review: Simon Dardis
llvm-svn: 325870
We won't be able to fold the constant pool load, but its still better than materialing ones and xoring for the invert if we used PCMPEQ.
This will fix another regression from D42948.
llvm-svn: 325845
This patch reverts r325440 and r325438 because it triggers an
assertion in SelectionDAGBuilder.cpp. Also having debug enabled
may unintentionally affect code-gen. The patch is reverted until
we find a better solution.
llvm-svn: 325825
There were no memory dependencies made between stores generated
when lowering formal arguments and loads generated when
call lowering byVal arguments which made the Post-RA scheduler
place a load before a matching store.
Make the fixed object stored to mutable so that the load
instructions can have their memory dependencies added
Set the frame object as isAliased which clears the underlying
objects vector in ScheduleDAGInstrs::buildSchedGraph().
This results in addition of all stores as dependenies for loads.
This problem appeared when passing a byVal parameter
coupled with a fastcc function call.
Differential Revision: https://reviews.llvm.org/D37515
llvm-svn: 325782
Fixup to rL325573 for large xor constants.
Thanks to Eli Friedman for the catch.
Differential revision: https://reviews.llvm.org/D43549
llvm-svn: 325761
This is a follow up of r325012, that allowed half types in constant pools.
Proper alignment was enforced when a big basic block was split up, but not when
a CPE was placed before/after a block; the successor block had the wrong
alignment.
Differential Revision: https://reviews.llvm.org/D43580
llvm-svn: 325754
An FRem instruction inside a loop should prevent the loop from being converted
into a CTR loop since this is not an operation that is legal on any PPC
subtarget. This will always be a call to a library function which means the
loop will be invalid if this instruction is in the body.
Fixes PR36292.
llvm-svn: 325739
Enable multiple COPY hints to eliminate more COPYs during register allocation.
Note that this is something all targets should do, see
https://reviews.llvm.org/D38128.
Review: Krzysztof Parzyszek
llvm-svn: 325697
Global Dynamic and Local Dynamic call relocations only implicitly
reference __tls_get_addr; there is no connection in the ELF file between
the relocations and the symbol other than the specification for the
relocations' semantics. However, it still needs to be in the symbol
table despite the lack of explicit references to the symbol table entry,
since it needs to be bound at link time for these relocations, otherwise
any objects will fail to link.
For details, see https://sourceware.org/bugzilla/show_bug.cgi?id=22832.
Path by: James Clarke (jrtc27)
Differential revision: https://reviews.llvm.org/D43271
llvm-svn: 325688
Cannon Lake does not support CLWB, therefore it
does not include all features listed under SKX anymore.
Instead, enumerate all SKX features with the exception of CLWB.
Patch by Gabor Buella
Differential Revision: https://reviews.llvm.org/D43380
llvm-svn: 325654
This patch provides mitigation for CVE-2017-5715, Spectre variant two,
which affects the P5600 and P6600. It implements the LLVM part of
-mindirect-jump=hazard. It is _not_ enabled by default for the P5600.
The migitation strategy suggested by MIPS for these processors is to use
hazard barrier instructions. 'jalr.hb' and 'jr.hb' are hazard
barrier variants of the 'jalr' and 'jr' instructions respectively.
These instructions impede the execution of instruction stream until
architecturally defined hazards (changes to the instruction stream,
privileged registers which may affect execution) are cleared. These
instructions in MIPS' designs are not speculated past.
These instructions are used with the attribute +use-indirect-jump-hazard
when branching indirectly and for indirect function calls.
These instructions are defined by the MIPS32R2 ISA, so this mitigation
method is not compatible with processors which implement an earlier
revision of the MIPS ISA.
Performance benchmarking of this option with -fpic and lld using
-z hazardplt shows a difference of overall 10%~ time increase
for the LLVM testsuite. Certain benchmarks such as methcall show a
substantially larger increase in time due to their nature.
Reviewers: atanasyan, zoran.jovanovic
Differential Revision: https://reviews.llvm.org/D43486
llvm-svn: 325653
This is split off from D42948 and includes just the cases that constant fold to true or false. It also includes some refactoring to keep predicate checks together.
This supports things like
(setcc uge X, 0) -> true
Differential Revision: https://reviews.llvm.org/D43489
llvm-svn: 325627
Get rid of icky goto loops and make the code easier to maintain. Otherwise,
NFC.
Restore r324903 and fix PR36369.
Differentail revision: https://reviews.llvm.org/D43364
llvm-svn: 325621
SimplifyDemandedBits forces the demanded mask to all 1s if the node has multiple uses, unless the AssumeSingleUse flag is set.
So previously we were only really likely to simplify something if the condition had a single use. And on the off chance we did simplify with multiple uses the demanded mask being used was all ones so there was no reason to create a shrunkblend.
This patch now checks that the condition is only used by selects first, and then sets the AssumeSingleUse flag for the simplifcation. Then we convert the selects to shrunkblend, and finally replace condition.
Differential Revision: https://reviews.llvm.org/D43446
llvm-svn: 325604
