Summary:
Sandy Bridge and later CPUs have better throughput using a SHLD to implement rotate versus the normal rotate instructions. Additionally it saves one uop and avoids a partial flag update dependency.
This patch implements this change on any Sandy Bridge or later processor without BMI2 instructions. With BMI2 we will use RORX as we currently do.
Reviewers: zvi
Reviewed By: zvi
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D30181
llvm-svn: 295697
We only implemented it for one of the 3 HLE instructions and that instruction is also under the RTM flag. Clang only implements the RTM flag from its command line.
llvm-svn: 294562
This patch does the following.
1. Adds an Intrinsic int_x86_clzero which works with __builtin_ia32_clzero
2. Identifies clzero feature using cpuid info. (Function:8000_0008, Checks if EBX[0]=1)
3. Adds the clzero feature under znver1 architecture.
4. The custom inserter is added in Lowering.
5. A testcase is added to check the intrinsic.
6. The clzero instruction is added to assembler test.
Patch by Ganesh Gopalasubramanian with a couple formatting tweaks, a disassembler test, and using update_llc_test.py from me.
Differential revision: https://reviews.llvm.org/D29385
llvm-svn: 294558
Enable the next form (intel style):
"mov <reg64>, <largeImm>"
which is should be available,
where <largeImm> stands for immediates which exceed the range of a singed 32bit integer
Differential Revision: https://reviews.llvm.org/D28988
llvm-svn: 293030
This patch fixes bugzilla 31576 (https://llvm.org/bugs/show_bug.cgi?id=31576).
"data32" instruction prefix was not defined in the llvm.
An exception had to be added to the X86 tablegen and AsmPrinter because both "data16" and "data32" are encoded to 0x66 (but in different modes).
Differential Revision: https://reviews.llvm.org/D28468
llvm-svn: 292352
Summary:
Attaching !absolute_symbol to a global variable does two things:
1) Marks it as an absolute symbol reference.
2) Specifies the value range of that symbol's address.
Teach the X86 backend to allow absolute symbols to appear in place of
immediates by extending the relocImm and mov64imm32 matchers. Start using
relocImm in more places where it is legal.
As previously proposed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2016-October/105800.html
Differential Revision: https://reviews.llvm.org/D25878
llvm-svn: 289087
Suspected to be the cause of a sanitizer-windows bot failure:
Assertion failed: isImm() && "Wrong MachineOperand accessor", file C:\b\slave\sanitizer-windows\llvm\include\llvm/CodeGen/MachineOperand.h, line 420
llvm-svn: 286385
A relocatable immediate is either an immediate operand or an operand that
can be relocated by the linker to an immediate, such as a regular symbol
in non-PIC code.
Start using relocImm for 32-bit and 64-bit MOV instructions, and for operands
of type "imm32_su". Remove a number of now-redundant patterns.
Differential Revision: https://reviews.llvm.org/D25812
llvm-svn: 286384
This change adds transformations such as:
zext(or(setcc(eq, (cmp x, 0)), setcc(eq, (cmp y, 0))))
To:
srl(or(ctlz(x), ctlz(y)), log2(bitsize(x))
This optimisation is beneficial on Jaguar architecture only, where lzcnt has a good reciprocal throughput.
Other architectures such as Intel's Haswell/Broadwell or AMD's Bulldozer/PileDriver do not benefit from it.
For this reason the change also adds a "HasFastLZCNT" feature which gets enabled for Jaguar.
Differential Revision: https://reviews.llvm.org/D23446
llvm-svn: 284248
Implement 'retn' simply by aliasing it to the relevant 'ret' instruction
Commit on behalf of coby
Differential Revision: https://reviews.llvm.org/D24346
llvm-svn: 282601
This patch handles 64-bit constants which can be encoded as 32-bit immediates.
It extends the functionality added by https://reviews.llvm.org/D11363 for 32-bit constants to 64-bit constants.
Patch by Sunita Marathe!
Differential Revision: https://reviews.llvm.org/D23391
llvm-svn: 278857
We've been pretending that segments are i8imm since the initial
support (r68645), predating the addition of the SEGMENT_REG class
(r81895). That happens to works, but is wrong, and inconsistent
with how we print (e.g., X86ATTInstPrinter::printMemReference)
and parse them (e.g., X86Operand::addMemOperands).
This change shouldn't affect any tool users, but is visible to
library users or out-of-tree tablegen backends: this causes
MCOperandInfo for the segment op to have an RC instead of "unknown",
and TII::getRegClass to actually return something. As the registers
are reserved and no vregs of the class ever created, that shouldn't
change anything.
No test change; no suspicious getRegClass() in X86 and CodeGen.
llvm-svn: 271559
This adds support to the backed to actually support SjLj EH as an exception
model. This is *NOT* the default model, and requires explicitly opting into it
from the frontend. GCC supports this model and for MinGW can still be enabled
via the `--using-sjlj-exceptions` options.
Addresses PR27749!
llvm-svn: 271244
with an additional fix to make RegAllocFast ignore undef physreg uses. It would
previously get confused about the "push %eax" instruction's use of eax. That
method for adjusting the stack pointer is used in X86FrameLowering::emitSPUpdate
as well, but since that runs after register-allocation, we didn't run into the
RegAllocFast issue before.
llvm-svn: 269949
Summary:
MONITORX/MWAITX instructions provide similar capability to the MONITOR/MWAIT
pair while adding a timer function, such that another termination of the MWAITX
instruction occurs when the timer expires. The presence of the MONITORX and
MWAITX instructions is indicated by CPUID 8000_0001, ECX, bit 29.
The MONITORX and MWAITX instructions are intercepted by the same bits that
intercept MONITOR and MWAIT. MONITORX instruction establishes a range to be
monitored. MWAITX instruction causes the processor to stop instruction execution
and enter an implementation-dependent optimized state until occurrence of a
class of events.
Opcode of MONITORX instruction is "0F 01 FA". Opcode of MWAITX instruction is
"0F 01 FB". These opcode information is used in adding tests for the
disassembler.
These instructions are enabled for AMD's bdver4 architecture.
Patch by Ganesh Gopalasubramanian!
Reviewers: echristo, craig.topper, RKSimon
Subscribers: RKSimon, joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D19795
llvm-svn: 269911
This patch moves the expansion of WIN_ALLOCA pseudo-instructions
into a separate pass that walks the CFG and lowers the instructions
based on a conservative estimate of the offset between the stack
pointer and the lowest accessed stack address.
The goal is to reduce binary size and run-time costs by removing
calls to _chkstk. While it doesn't fix all the code quality problems
with inalloca calls, it's an incremental improvement for PR27076.
Differential Revision: http://reviews.llvm.org/D20263
llvm-svn: 269828
This is the same as r255936, with added logic for avoiding clobbering of the
red zone (PR26023).
Differential Revision: http://reviews.llvm.org/D18246
llvm-svn: 264375
cmpxchg[8|16]b uses RBX as one of its argument.
In other words, using this instruction clobbers RBX as it is defined to hold one
the input. When the backend uses dynamically allocated stack, RBX is used as a
reserved register for the base pointer.
Reserved registers have special semantic that only the target understands and
enforces, because of that, the register allocator don’t use them, but also,
don’t try to make sure they are used properly (remember it does not know how
they are supposed to be used).
Therefore, when RBX is used as a reserved register but defined by something that
is not compatible with that use, the register allocator will not fix the
surrounding code to make sure it gets saved and restored properly around the
broken code. This is the responsibility of the target to do the right thing with
its reserved register.
To fix that, when the base pointer needs to be preserved, we use a different
pseudo instruction for cmpxchg that save rbx.
That pseudo takes two more arguments than the regular instruction:
- One is the value to be copied into RBX to set the proper value for the
comparison.
- The other is the virtual register holding the save of the value of RBX as the
base pointer. This saving is done as part of isel (i.e., we emit a copy from
rbx).
cmpxchg_save_rbx <regular cmpxchg args>, input_for_rbx_reg, save_of_rbx_as_bp
This gets expanded into:
rbx = copy input_for_rbx_reg
cmpxchg <regular cmpxchg args>
rbx = save_of_rbx_as_bp
Note: The actual modeling of the pseudo is a bit more complicated to make sure
the interferes that appears after the pseudo gets expanded are properly modeled
before that expansion.
This fixes PR26883.
llvm-svn: 263325
The x86 ret instruction has a 16 bit immediate indicating how many bytes
to pop off of the stack beyond the return address.
There is a problem when extremely large structs are passed by value: we
might not be able to fit the number of bytes to pop into the return
instruction.
To fix this, expand RET_FLAG a little later and use a special sequence
to clean the stack:
pop %ecx ; return address is now in %ecx
add $n, %esp ; clean the stack
push %ecx ; bring the return address back on the stack
ret ; pop the return address and jmp to it's value
llvm-svn: 262755
We modeled the RDFLAGS{32,64} operations as "using" {E,R}FLAGS.
While technically correct, this is not be desirable for folks who want
to examine aspects of the FLAGS register which are not related to
computation like whether or not CPUID is a valid instruction.
Differential Revision: http://reviews.llvm.org/D17782
llvm-svn: 262465
This is long-standing dirtiness, as acknowledged by r77582:
The current trick is to select it into a merge_values with
the first definition being an implicit_def. The proper solution is
to add new ISD opcodes for the no-output variant.
Doing this before selection will let us combine away some constructs.
Differential Revision: http://reviews.llvm.org/D17659
llvm-svn: 262244
As shown in:
https://llvm.org/bugs/show_bug.cgi?id=23203
...we currently die because lowering believes that mfence is allowed without SSE2 on x86-64,
but the instruction def doesn't know that.
I don't know if allowing mfence without SSE is right, but if not, at least now it's consistently wrong. :)
Differential Revision: http://reviews.llvm.org/D17219
llvm-svn: 260828
This is a fix for https://llvm.org/bugs/show_bug.cgi?id=22796.
The previous implementation of ClassInfo::operator< allowed cycles of classes
such that x < y < z < x, meaning that a list of them cannot be correctly
sorted, and the sort order could differ with different standard libraries.
The original implementation sorted classes by ValueName if they were otherwise
equal. This isn't strictly necessary, but some backends seem to accidentally
rely on it. If I reverse this comparison I get 8 test failures spread across
the AArch64, Mips and X86 backends, so I have left it in until those backends
can be fixed.
There was one case in the X86 backend where the observable behaviour of the
assembler is changed by this patch. This was because some of the memory asm
operands were not marked as children of X86MemAsmOperand.
Differential Revision: http://reviews.llvm.org/D16141
llvm-svn: 258677
Changes in X86.td:
I set features of Intel processors in incremental form: IVB = SNB + X HSW = IVB + X ..
I added Skylake client processor and defined it's features
FeatureADX was missing on KNL
Added some new features to appropriate processors SMAP, IFMA, PREFETCHWT1, VMFUNC and others
Differential Revision: http://reviews.llvm.org/D16357
llvm-svn: 258659
The following are legal according to X86 spec:
ins mem, DX
outs DX, mem
lods mem
stos mem
scas mem
cmps mem, mem
movs mem, mem
Differential Revision: http://reviews.llvm.org/D14827
llvm-svn: 258132
Craig Topper