When we see a non flag-setting instruction for which only the flag-setting
version is available in Thumb1, we should give a better error message than
"invalid instruction".
Differential Revision: https://reviews.llvm.org/D27414
llvm-svn: 288805
Instead, expose whether the current type is an array or a struct, if an array
what the upper bound is, and if a struct the struct type itself. This is
in preparation for a later change which will make PointerType derive from
Type rather than SequentialType.
Differential Revision: https://reviews.llvm.org/D26594
llvm-svn: 288458
Summary:
This patch fixes comparison of 64-bit atomic with its expected value in CMP_SWAP_64 expansion.
Currently, the low words are compared with CMP, while the high words are compared with SBC. SBC expects the carry flag to be set if CMP detects a difference. CMP might leave the carry unset for unequal arguments though if the first one is >= than the second. This might cause the comparison logic to detect false equality.
Example of the broken C++ code:
```
std::atomic<long long> at(2);
long long ll = 1;
std::atomic_compare_exchange_strong(&at, &ll, 3);
```
Even though the atomic `at` and the expected value `ll` are not equal and `atomic_compare_exchange_strong` returns `false`, `at` is changed to 3.
The patch replaces SBC with CMPEQ.
Reviewers: t.p.northover
Subscribers: aemerson, rengolin, llvm-commits, asl
Differential Revision: https://reviews.llvm.org/D27315
llvm-svn: 288433
Recommitting r288293 with some extra fixes for GlobalISel code.
Most of the exception handling members in MachineModuleInfo is actually
per function data (talks about the "current function") so it is better
to keep it at the function instead of the module.
This is a necessary step to have machine module passes work properly.
Also:
- Rename TidyLandingPads() to tidyLandingPads()
- Use doxygen member groups instead of "//===- EH ---"... so it is clear
where a group ends.
- I had to add an ugly const_cast at two places in the AsmPrinter
because the available MachineFunction pointers are const, but the code
wants to call tidyLandingPads() in between
(markFunctionEnd()/endFunction()).
Differential Revision: https://reviews.llvm.org/D27227
llvm-svn: 288405
Most of the exception handling members in MachineModuleInfo is actually
per function data (talks about the "current function") so it is better
to keep it at the function instead of the module.
This is a necessary step to have machine module passes work properly.
Also:
- Rename TidyLandingPads() to tidyLandingPads()
- Use doxygen member groups instead of "//===- EH ---"... so it is clear
where a group ends.
- I had to add an ugly const_cast at two places in the AsmPrinter
because the available MachineFunction pointers are const, but the code
wants to call tidyLandingPads() in between
(markFunctionEnd()/endFunction()).
Differential Revision: https://reviews.llvm.org/D27227
llvm-svn: 288293
This is per function data so it is better kept at the function instead
of the module.
This is a necessary step to have machine module passes work properly.
Differential Revision: https://reviews.llvm.org/D27185
llvm-svn: 288291
No test case necessary as the problematic condition is checked with the
newly introduced assertAllSuperRegsMarked() function.
Differential Revision: https://reviews.llvm.org/D26648
llvm-svn: 288277
No-one actually had a mangler handy when calling this function, and
getSymbol itself went most of the way towards getting its own mangler
(with a local TLOF variable) so forcing all callers to supply one was
just extra complication.
llvm-svn: 287645
Summary:
Variadic functions can be treated in the same way as normal functions
with respect to the number and types of parameters.
Reviewers: grosbach, olista01, t.p.northover, rengolin
Subscribers: javed.absar, aemerson, llvm-commits
Differential Revision: https://reviews.llvm.org/D26748
llvm-svn: 287219
One half of the shifts obviously needed conditional selection based on whether
the shift amount is more than 32-bits, but leaving the other half as the
natural shift isn't acceptable either: it's undefined behaviour to shift a
32-bit value by more than 31.
llvm-svn: 287149
Move some code inside the proper 'if' block to make sure it is only run once,
when the subtarget is first created. Things can still break if we use different
ARM target machines or if we have functions with different 'target-cpu' or
'target-features', we should fix that too in the future.
llvm-svn: 286974
This patch adds the Sched Machine Model for Cortex-R52.
Details of the pipeline and descriptions are in comments
in file ARMScheduleR52.td included in this patch.
Reviewers: rengolin, jmolloy
Differential Revision: https://reviews.llvm.org/D26500
llvm-svn: 286949
For example we were producing
push {r8, r10, r11, r4, r5, r7, lr}
This is misleading (r4, r5 and r7 are actually pushed before the rest), and
other components (stack folding recently) often forget to deal with the extra
complexity coming from the different order, leading to miscompiles. Finally, we
warn about our own code in -no-integrated-as mode without this, which is really
not a good idea.
Fixed usage of std::sort so that we (hopefully) use instantiations that
actually exist in GCC 4.8.
llvm-svn: 286881
For example we were producing
push {r8, r10, r11, r4, r5, r7, lr}
This is misleading (r4, r5 and r7 are actually pushed before the rest), and
other components (stack folding recently) often forget to deal with the extra
complexity coming from the different order, leading to miscompiles. Finally, we
warn about our own code in -no-integrated-as mode without this, which is really
not a good idea.
llvm-svn: 286866
The version of this instruction with the .w suffix already correctly accepts
this, but the alias without the .w did not.
Differential Revision: https://reviews.llvm.org/D26499
llvm-svn: 286446
When the base register (register pointing to the jump table) is the PC, we expect the jump table to directly follow the jump sequence with no intervening padding.
If there is intervening padding, the calculated offsets will not be correct. One solution would be to account for any padding in the emitted LDRB instruction, but at the moment we don't support emitting MCExprs for the load offset.
In the meantime, it's correct and only a slight amount worse to just move the padding up, from just before the jump table to just before the jump instruction sequence. We can do that by emitting code alignment before the jump sequence, as we know the number of instructions in the sequence is always 4.
llvm-svn: 286107
This handles the last case of the builtin function calls that we would
generate code which differed from Microsoft's ABI. Rather than
generating a call to `__pow{d,s}i2` we now promote the parameter to a
float or double and invoke `powf` or `pow` instead.
Addresses PR30825!
llvm-svn: 286082
Summary: ARMv6m supports dmb etc fench instructions but not ldrex/strex etc. So for some atomic load/store, LLVM should inline instructions instead of lowering to __sync_ calls.
Reviewers: rengolin, efriedma, t.p.northover, jmolloy
Subscribers: efriedma, aemerson, llvm-commits
Differential Revision: https://reviews.llvm.org/D26120
llvm-svn: 285969
This recommits r281323, which was backed out for two reasons. One, a selfhost failure, and two, it apparently caused Chromium failures. Actually, the latter was a red herring. The log has expired from the former, but I suspect that was a red herring too (actually caused by another problematic patch of mine). Therefore reapplying, and will watch the bots like a hawk.
For the common pattern (CMPZ (AND x, #bitmask), #0), we can do some more efficient instruction selection if the bitmask is one consecutive sequence of set bits (32 - clz(bm) - ctz(bm) == popcount(bm)).
1) If the bitmask touches the LSB, then we can remove all the upper bits and set the flags by doing one LSLS.
2) If the bitmask touches the MSB, then we can remove all the lower bits and set the flags with one LSRS.
3) If the bitmask has popcount == 1 (only one set bit), we can shift that bit into the sign bit with one LSLS and change the condition query from NE/EQ to MI/PL (we could also implement this by shifting into the carry bit and branching on BCC/BCS).
4) Otherwise, we can emit a sequence of LSLS+LSRS to remove the upper and lower zero bits of the mask.
1-3 require only one 16-bit instruction and can elide the CMP. 4 requires two 16-bit instructions but can elide the CMP and doesn't require materializing a complex immediate, so is also a win.
llvm-svn: 285893
As it stands, the OperandMatchResultTy is only included in the generated
header if there is custom operand parsing. However, almost all backends
make use of MatchOperand_Success and friends from OperandMatchResultTy for
e.g. parseRegister. This is a pain when starting an AsmParser for a new
backend that doesn't yet have custom operand parsing. Move the enum to
MCTargetAsmParser.h.
This patch is a prerequisite for D23563
Differential Revision: https://reviews.llvm.org/D23496
llvm-svn: 285705
[Reapplying r284580 and r285917 with fix and testing to ensure emitted jump tables for Thumb-1 have 4-byte alignment]
The TBB and TBH instructions in Thumb-2 allow jump tables to be compressed into sequences of bytes or shorts respectively. These instructions do not exist in Thumb-1, however it is possible to synthesize them out of a sequence of other instructions.
It turns out this sequence is so short that it's almost never a lose for performance and is ALWAYS a significant win for code size.
TBB example:
Before: lsls r0, r0, #2 After: add r0, pc
adr r1, .LJTI0_0 ldrb r0, [r0, #6]
ldr r0, [r0, r1] lsls r0, r0, #1
mov pc, r0 add pc, r0
=> No change in prologue code size or dynamic instruction count. Jump table shrunk by a factor of 4.
The only case that can increase dynamic instruction count is the TBH case:
Before: lsls r0, r4, #2 After: lsls r4, r4, #1
adr r1, .LJTI0_0 add r4, pc
ldr r0, [r0, r1] ldrh r4, [r4, #6]
mov pc, r0 lsls r4, r4, #1
add pc, r4
=> 1 more instruction in prologue. Jump table shrunk by a factor of 2.
So there is an argument that this should be disabled when optimizing for performance (and a TBH needs to be generated). I'm not so sure about that in practice, because on small cores with Thumb-1 performance is often tied to code size. But I'm willing to turn it off when optimizing for performance if people want (also note that TBHs are fairly rare in practice!)
llvm-svn: 285690
Generate the slowest possible codepath for noopt CodeGen. Even trying to be
clever with the negated jump can cause out-of-range jumps. Use a wide branch
instead. Although the code is modelled simplistically, the later optimizations
would recombine the branching into `cbz` if possible. This re-enables the
previous optimization as well as hopefully gives us working code in all cases.
Addresses PR30356!
llvm-svn: 285649
The Windows ARM target expects the compiler to emit a division-by-zero check.
The check would use the form of:
cmp r?, #0
cbz .Ltrap
b .Lbody
.Lbody:
...
.Ltrap:
udf #249 @ __brkdiv0
This works great most of the time. However, if the body of the function is
greater than 127 bytes, the branch target limitation of cbz becomes an issue.
This occurs in the unoptimized code generation cases sometimes (like in
compiler-rt).
Since this is a matter of correctness, possibly pay a small penalty instead. We
now form this slightly differently:
cbnz .Lbody
udf #249 @ __brkdiv0
.Lbody:
...
The positive case is through the branch instead of being the next instruction.
However, because of the basic block layout, the negated branch is going to be
a short distance always (2 bytes away, after the inserted __brkdiv0).
The new t__brkdiv0 instruction is required to explicitly mark the instruction as
a terminator as the generic UDF instruction is not a terminator.
Addresses PR30532!
llvm-svn: 285312
UMAAL is a DSP instruction and it is not available on thumbv7m
(Cortex-M3) and thumbv6m (Cortex-M0+1) targets. Also fix wrong
CHECK prefix in longMAC.ll test.
Patch by Vadzim Dambrouski.
Differential Revision: https://reviews.llvm.org/D25890
llvm-svn: 285278
It would be a very nice invariant to rely on, but unfortunately it doesn't
necessarily hold (and the causes of mis-sorted reglists appear to be quite
varied) so to be robust the frame lowering code can't assume that the first
register in the list is also the first one that actually gets pushed.
Should fix an issue where we were turning something like:
push {r8, r4, r7, lr}
sub sp, #24
into nonsense like:
push {r2, r3, r4, r5, r6, r7, r8, r4, r7, lr}
llvm-svn: 285232
Passing a MachineFunction as argument is more natural and avoids an
unnecessary round-trip through the logic determining the correct
Subtarget because MachineFunction already has a reference anyway.
llvm-svn: 285039
All of these existed because MSVC 2013 was unable to synthesize default
move ctors. We recently dropped support for it so all that error-prone
boilerplate can go.
No functionality change intended.
llvm-svn: 284721
The TBB and TBH instructions in Thumb-2 allow jump tables to be compressed into sequences of bytes or shorts respectively. These instructions do not exist in Thumb-1, however it is possible to synthesize them out of a sequence of other instructions.
It turns out this sequence is so short that it's almost never a lose for performance and is ALWAYS a significant win for code size.
TBB example:
Before: lsls r0, r0, #2 After: add r0, pc
adr r1, .LJTI0_0 ldrb r0, [r0, #6]
ldr r0, [r0, r1] lsls r0, r0, #1
mov pc, r0 add pc, r0
=> No change in prologue code size or dynamic instruction count. Jump table shrunk by a factor of 4.
The only case that can increase dynamic instruction count is the TBH case:
Before: lsls r0, r4, #2 After: lsls r4, r4, #1
adr r1, .LJTI0_0 add r4, pc
ldr r0, [r0, r1] ldrh r4, [r4, #6]
mov pc, r0 lsls r4, r4, #1
add pc, r4
=> 1 more instruction in prologue. Jump table shrunk by a factor of 2.
So there is an argument that this should be disabled when optimizing for performance (and a TBH needs to be generated). I'm not so sure about that in practice, because on small cores with Thumb-1 performance is often tied to code size. But I'm willing to turn it off when optimizing for performance if people want (also note that TBHs are fairly rare in practice!)
llvm-svn: 284580
This renames the function for checking FP function attribute values and also
adds more build attribute tests (which are in separate files because build
attributes are set per file).
Differential Revision: https://reviews.llvm.org/D25625
llvm-svn: 284571
The custom lowering is pretty straightforward: basically, just AND
together the two halves of a <4 x i32> compare.
Differential Revision: https://reviews.llvm.org/D25713
llvm-svn: 284536
This patch assigns cost of the scaling used in addressing for Cortex-R52.
On Cortex-R52 a negated register offset takes longer than a non-negated
register offset, in a register-offset addressing mode.
Differential Revision: http://reviews.llvm.org/D25670
Reviewer: jmolloy
llvm-svn: 284460
This patch adds simplified support for tail calls on ARM with XRay instrumentation.
Known issue: compiled with generic flags: `-O3 -g -fxray-instrument -Wall
-std=c++14 -ffunction-sections -fdata-sections` (this list doesn't include my
specific flags like --target=armv7-linux-gnueabihf etc.), the following program
#include <cstdio>
#include <cassert>
#include <xray/xray_interface.h>
[[clang::xray_always_instrument]] void __attribute__ ((noinline)) fC() {
std::printf("In fC()\n");
}
[[clang::xray_always_instrument]] void __attribute__ ((noinline)) fB() {
std::printf("In fB()\n");
fC();
}
[[clang::xray_always_instrument]] void __attribute__ ((noinline)) fA() {
std::printf("In fA()\n");
fB();
}
// Avoid infinite recursion in case the logging function is instrumented (so calls logging
// function again).
[[clang::xray_never_instrument]] void simplyPrint(int32_t functionId, XRayEntryType xret)
{
printf("XRay: functionId=%d type=%d.\n", int(functionId), int(xret));
}
int main(int argc, char* argv[]) {
__xray_set_handler(simplyPrint);
printf("Patching...\n");
__xray_patch();
fA();
printf("Unpatching...\n");
__xray_unpatch();
fA();
return 0;
}
gives the following output:
Patching...
XRay: functionId=3 type=0.
In fA()
XRay: functionId=3 type=1.
XRay: functionId=2 type=0.
In fB()
XRay: functionId=2 type=1.
XRay: functionId=1 type=0.
XRay: functionId=1 type=1.
In fC()
Unpatching...
In fA()
In fB()
In fC()
So for function fC() the exit sled seems to be called too much before function
exit: before printing In fC().
Debugging shows that the above happens because printf from fC is also called as
a tail call. So first the exit sled of fC is executed, and only then printf is
jumped into. So it seems we can't do anything about this with the current
approach (i.e. within the simplification described in
https://reviews.llvm.org/D23988 ).
Differential Revision: https://reviews.llvm.org/D25030
llvm-svn: 284456
Matthias Braun