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
The feature flag is for VPERMB,VPERMI2B,VPERMT2B and VPMULTISHIFTQB instructions.
More about the instruction can be found in:
hattps://software.intel.com/sites/default/files/managed/07/b7/319433-023.pdf
Differential Revision: http://reviews.llvm.org/D16190
llvm-svn: 258012
The red zone consists of 128 bytes beyond the stack pointer so that the
allocation of objects in leaf functions doesn't require decrementing
rsp. In r255656, we introduced an optimization that would cheaply
materialize certain constants via push/pop. Push decrements the stack
pointer and stores it's result at what is now the top of the stack.
However, this means that using push/pop would encroach on the red zone.
PR26023 gives an example where this corrupts an object in the red zone.
llvm-svn: 256808
LLVM's targets need to know if stack pointer adjustments occur after the
prologue. This is needed to correctly determine if the red-zone is
appropriate to use or if a frame pointer is required.
Normally, LLVM can figure this out very precisely by reasoning about the
contents of the MachineFunction. There is an interesting corner case:
inline assembly.
The vast majority of inline assembly which will perform a push or pop is
done so to pair up with pushf or popf as appropriate. Unfortunately,
this inline assembly doesn't mark the stack pointer as clobbered
because, well, it isn't. The stack pointer is decremented and then
immediately incremented. Because of this, LLVM was changed in r256456
to conservatively assume that inline assembly contain a sequence of
stack operations. This is unfortunate because the vast majority of
inline assembly will not end up manipulating the stack pointer in any
way at all.
Instead, let's provide a more principled solution: an intrinsic.
FWIW, other compilers (MSVC and GCC among them) also provide this
functionality as an intrinsic.
llvm-svn: 256685
Use the 3-byte (4 with REX prefix) push-pop sequence for materializing
small constants. This is smaller than using a mov (5, 6 or 7 bytes
depending on size and REX prefix), but it's likely to be slower, so
only used for 'minsize'.
This is a follow-up to r255656.
Differential Revision: http://reviews.llvm.org/D15549
llvm-svn: 255936
the feature flag is essential for RDPKRU and WRPKRU instruction
more about the instruction can be found in the SDM rev 56, vol 2 from http://www.intel.com/sdm
Differential Revision: http://reviews.llvm.org/D15491
llvm-svn: 255644
Part 1 was submitted in http://reviews.llvm.org/D15134.
Changes in this part:
* X86RegisterInfo.td, X86RecognizableInstr.cpp: Add FR128 register class.
* X86CallingConv.td: Pass f128 values in XMM registers or on stack.
* X86InstrCompiler.td, X86InstrInfo.td, X86InstrSSE.td:
Add instruction selection patterns for f128.
* X86ISelLowering.cpp:
When target has MMX registers, configure MVT::f128 in FR128RegClass,
with TypeSoftenFloat action, and custom actions for some opcodes.
Add missed cases of MVT::f128 in places that handle f32, f64, or vector types.
Add TODO comment to support f128 type in inline assembly code.
* SelectionDAGBuilder.cpp:
Fix infinite loop when f128 type can have
VT == TLI.getTypeToTransformTo(Ctx, VT).
* Add unit tests for x86-64 fp128 type.
Differential Revision: http://reviews.llvm.org/D11438
llvm-svn: 255558
FP logic instructions are supported in DQ extension on AVX-512 target.
I use integer operations instead.
Added tests.
I also enabled FABS in this patch in order to check ANDPS.
The operations are FOR, FXOR, FAND, FANDN.
The instructions, that supported for 512-bit vector under DQ are:
VORPS/PD, VXORPS/PD, VANDPS/PD, FANDNPS/PD.
Differential Revision: http://reviews.llvm.org/D15110
llvm-svn: 254913
According to x86 spec, loopz and loopnz should be supported for Intel syntax, where loopz is equivalent to loope and loopnz is equivalent to loopne.
Differential Revision: http://reviews.llvm.org/D15148
llvm-svn: 254877
These instructions are not supported by all CPUs in 64-bit mode. Emitting them
causes Chromium to crash on start-up for users with such chips.
(GCC puts these instructions behind -msahf on 64-bit for the same reason.)
This patch adds FeatureLAHFSAHF, enables it by default for 32-bit targets
and modern CPUs, and changes X86InstrInfo::copyPhysReg back to the lowering
from before r244503 when the instructions are not available.
Differential Revision: http://reviews.llvm.org/D15240
llvm-svn: 254793
LLVM Missing the following instructions: fadd\fdiv\fmul\fsub\fsubr\fdivr.
GAS and MS supporting this instruction and lowering them in to a faddp\fdivp\fmulp\fsubp\fsubrp\fdivrp instructions.
Differential Revision: http://reviews.llvm.org/D14217
llvm-svn: 252908
This makes catchret look more like a branch, and less like a weird use
of BlockAddress. It also lets us get away from
llvm.x86.seh.restoreframe, which relies on the old parentfpoffset label
arithmetic.
llvm-svn: 247936
All of the complexity is in cleanupret, and it mostly follows the same
codepaths as catchret, except it doesn't take a return value in RAX.
This small example now compiles and executes successfully on win32:
extern "C" int printf(const char *, ...) noexcept;
struct Dtor {
~Dtor() { printf("~Dtor\n"); }
};
void has_cleanup() {
Dtor o;
throw 42;
}
int main() {
try {
has_cleanup();
} catch (int) {
printf("caught it\n");
}
}
Don't try to put the cleanup in the same function as the catch, or Bad
Things will happen.
llvm-svn: 247219
The old implementation assumed LP64 which is broken for x32. Specifically, the
MOVE8rm_NOREX and MOVE8mr_NOREX, when selected, would cause a 'Cannot emit
physreg copy instruction' error message to be reported.
This patch also enable the h-register*ll tests for x32.
Differential Revision: http://reviews.llvm.org/D12336
Patch by João Porto
llvm-svn: 247058
We can now run 32-bit programs with empty catch bodies. The next step
is to change PEI so that we get funclet prologues and epilogues.
llvm-svn: 246235
First step in preventing immediates that occur more than once within a single
basic block from being pulled into their users, in order to prevent unnecessary
large instruction encoding .Currently enabled only when optimizing for size.
Patch by: zia.ansari@intel.com
Differential Revision: http://reviews.llvm.org/D11363
llvm-svn: 244601
REPE, REPZ, REPNZ, REPNE should have mnemonics for Intel syntax as well.
Currently using these instructions causes compilation errors for Intel syntax.
Differential Revision: http://reviews.llvm.org/D11794
llvm-svn: 244584
The "imul reg, imm" alias is not defined for intel syntax.
In intel syntax there is no w/l/q suffix for the imul instruction.
Differential Revision: http://reviews.llvm.org/D11887
llvm-svn: 244582
Adds pushes to the folding tables.
This also required a fix to the TD definition, since the memory forms of
the push instructions did not have the right mayLoad/mayStore flags.
Differential Revision: http://reviews.llvm.org/D11340
llvm-svn: 243010
Summary:
Initially, these intrinsics seemed like part of a family of "frame"
related intrinsics, but now I think that's more confusing than helpful.
Initially, the LangRef specified that this would create a new kind of
allocation that would be allocated at a fixed offset from the frame
pointer (EBP/RBP). We ended up dropping that design, and leaving the
stack frame layout alone.
These intrinsics are really about sharing local stack allocations, not
frame pointers. I intend to go further and add an `llvm.localaddress()`
intrinsic that returns whatever register (EBP, ESI, ESP, RBX) is being
used to address locals, which should not be confused with the frame
pointer.
Naming suggestions at this point are welcome, I'm happy to re-run sed.
Reviewers: majnemer, nicholas
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D11011
llvm-svn: 241633
Correctly support assembling "pushw $imm8" on x86-64 targets.
Also some cleanup of the PUSH instructions (PUSH64i16 and PUSHi16 actually
represent the same instruction)
This fixes PR23996
Patch by: david.l.kreitzer@intel.com
Differential Revision: http://reviews.llvm.org/D10878
llvm-svn: 241404
