-march=armv8.1-m.main+mve.fp+nomve -mfpu=none should disable FP
registers and instructions moving to/from FP registers.
This patch fixes the case when "+mve" (added to the feature list by
"+mve.fp"), is followed by "-mve" (added by "+nomve").
Differential Revision: https://reviews.llvm.org/D72633
Architecturally, it's allowed to have MVE-I without an FPU, thus
-mfpu=none should not disable MVE-I, or moves to/from FP-registers.
This patch removes `+/-fpregs` from features unconditionally added to
target feature list, depending on FPU and moves the logic to Clang
driver, where the negative form (`-fpregs`) is conditionally added to
the target features list for the cases of `-mfloat-abi=soft`, or
`-mfpu=none` without either `+mve` or `+mve.fp`. Only the negative
form is added by the driver, the positive one is derived from other
features in the backend.
Differential Revision: https://reviews.llvm.org/D71843
Since `-mfloat-abi=soft` is taken to mean turning off all uses of the
FP registers, it should turn off the MVE vector instructions as well
as NEON and scalar FP. But it wasn't doing so.
So the options `-march=armv8.1-m.main+mve.fp+fp.dp -mfloat-abi=soft`
would cause the underlying LLVM to //not// support MVE (because it
knows the real target feature relationships and turned off MVE when
the `fpregs` feature was removed), but the clang layer still thought
it //was// supported, and would misleadingly define the feature macro
`__ARM_FEATURE_MVE`.
The ARM driver code already has a long list of feature names to turn
off when `-mfloat-abi=soft` is selected. The fix is to add the missing
entries `mve` and `mve.fp` to that list.
Reviewers: dmgreen
Subscribers: kristof.beyls, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D69025
llvm-svn: 375001
Change D60691 caused some knock-on failures that weren't caught by the
existing tests. Firstly, selecting a CPU that should have had a
restricted FPU (e.g. `-mcpu=cortex-m4`, which should have 16 d-regs
and no double precision) could give the unrestricted version, because
`ARM::getFPUFeatures` returned a list of features including subtracted
ones (here `-fp64`,`-d32`), but `ARMTargetInfo::initFeatureMap` threw
away all the ones that didn't start with `+`. Secondly, the
preprocessor macros didn't reliably match the actual compilation
settings: for example, `-mfpu=softvfp` could still set `__ARM_FP` as
if hardware FP was available, because the list of features on the cc1
command line would include things like `+vfp4`,`-vfp4d16` and clang
didn't realise that one of those cancelled out the other.
I've fixed both of these issues by rewriting `ARM::getFPUFeatures` so
that it returns a list that enables every FP-related feature
compatible with the selected FPU and disables every feature not
compatible, which is more verbose but means clang doesn't have to
understand the dependency relationships between the backend features.
Meanwhile, `ARMTargetInfo::handleTargetFeatures` is testing for all
the various forms of the FP feature names, so that it won't miss cases
where it should have set `HW_FP` to feed into feature test macros.
That in turn caused an ordering problem when handling `-mcpu=foo+bar`
together with `-mfpu=something_that_turns_off_bar`. To fix that, I've
arranged that the `+bar` suffixes on the end of `-mcpu` and `-march`
cause feature names to be put into a separate vector which is
concatenated after the output of `getFPUFeatures`.
Another side effect of all this is to fix a bug where `clang -target
armv8-eabi` by itself would fail to set `__ARM_FEATURE_FMA`, even
though `armv8` (aka Arm v8-A) implies FP-Armv8 which has FMA. That was
because `HW_FP` was being set to a value including only the `FPARMV8`
bit, but that feature test macro was testing only the `VFP4FPU` bit.
Now `HW_FP` ends up with all the bits set, so it gives the right
answer.
Changes to tests included in this patch:
* `arm-target-features.c`: I had to change basically all the expected
results. (The Cortex-M4 test in there should function as a
regression test for the accidental double-precision bug.)
* `arm-mfpu.c`, `armv8.1m.main.c`: switched to using `CHECK-DAG`
everywhere so that those tests are no longer sensitive to the order
of cc1 feature options on the command line.
* `arm-acle-6.5.c`: been updated to expect the right answer to that
FMA test.
* `Preprocessor/arm-target-features.c`: added a regression test for
the `mfpu=softvfp` issue.
Reviewers: SjoerdMeijer, dmgreen, ostannard, samparker, JamesNagurne
Reviewed By: ostannard
Subscribers: srhines, javed.absar, kristof.beyls, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D62998
llvm-svn: 362791
The recent change D60691 introduced a bug in clang when handling
option combinations such as `-mcpu=cortex-m4 -mfpu=none`. Those
options together should select Cortex-M4 but disable all use of
hardware FP, but in fact, now hardware FP instructions can still be
generated in that mode.
The reason is because the handling of FPUVersion::NONE disables all
the same feature names it used to, of which the base one is `vfp2`.
But now there are further features below that, like `vfp2d16fp` and
(following D60694) `fpregs`, which also need to be turned off to
disable hardware FP completely.
Added a tiny test which double-checks that compiling a simple FP
function doesn't access the FP registers.
Reviewers: SjoerdMeijer, dmgreen
Reviewed By: dmgreen
Subscribers: lebedev.ri, javed.absar, kristof.beyls, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D62729
llvm-svn: 362380
Those two subtarget features were awkward because their semantics are
reversed: each one indicates the _lack_ of support for something in
the architecture, rather than the presence. As a consequence, you
don't get the behavior you want if you combine two sets of feature
bits.
Each SubtargetFeature for an FP architecture version now comes in four
versions, one for each combination of those options. So you can still
say (for example) '+vfp2' in a feature string and it will mean what
it's always meant, but there's a new string '+vfp2d16sp' meaning the
version without those extra options.
A lot of this change is just mechanically replacing positive checks
for the old features with negative checks for the new ones. But one
more interesting change is that I've rearranged getFPUFeatures() so
that the main FPU feature is appended to the output list *before*
rather than after the features derived from the Restriction field, so
that -fp64 and -d32 can override defaults added by the main feature.
Reviewers: dmgreen, samparker, SjoerdMeijer
Subscribers: srhines, javed.absar, eraman, kristof.beyls, hiraditya, zzheng, Petar.Avramovic, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D60691
llvm-svn: 361845
Summary:
There are an insignificant number of ARM Android devices that don't
support NEON. Default to using NEON since that will improve
performance on the majority of devices. Users that need to target
non-NEON devices can still explicitly disable NEON.
Reviewers: srhines, pirama, kristof.beyls
Reviewed By: pirama
Subscribers: efriedma, javed.absar, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D58153
llvm-svn: 354166
Summary:
Android mandates that devices have at least vfpv3-d16 until
Marshmallow and NEON after that. Still honor the user's decision, but
raise the defaults for Android targets.
Reviewers: srhines, pirama, javed.absar, kristof.beyls, peter.smith
Reviewed By: peter.smith
Subscribers: peter.smith, rengolin, kristof.beyls, chrib, cfe-commits
Differential Revision: https://reviews.llvm.org/D53121
llvm-svn: 344367
To be compatible with GCC if soft floating point is in effect any FPU
specified is effectively ignored, eg,
-mfloat-abi=soft -fpu=neon
If any floating point features which require FPU hardware are enabled
they must be disable.
There was some support for doing this for NEON, but it did not handle
VFP, nor did it prevent the backend from emitting the build attribute
Tag_FP_arch describing the generated code as using the floating point
hardware if a FPU was specified (even though soft float does not use
the FPU).
Disabling the hardware floating point features for targets which are
compiling for soft float has meant that some tests which were incorrectly
checking for hardware support also needed to be updated. In such cases,
where appropriate the tests have been updated to check compiling for
soft float and a non-soft float variant (usually softfp). This was
usually because the target specified in the test defaulted to soft float.
Differential Revision: https://reviews.llvm.org/D42569
llvm-svn: 325492
To be compatible with GCC if soft floating point is in effect any FPU
specified is effectively ignored, eg,
-mfloat-abi=soft -fpu=neon
If any floating point features which require FPU hardware are enabled
they must be disable.
There was some support for doing this for NEON, but it did not handle
VFP, nor did it prevent the backend from emitting the build attribute
Tag_FP_arch describing the generated code as using the floating point
hardware if a FPU was specified (even though soft float does not use
the FPU).
Disabling the hardware floating point features for targets which are
compiling for soft float has meant that some tests which were incorrectly
checking for hardware support also needed to be updated. In such cases,
where appropriate the tests have been updated to check compiling for
soft float and a non-soft float variant (usually softfp). This was
usually because the target specified in the test defaulted to soft float.
Differential Revision: https://reviews.llvm.org/D40256
llvm-svn: 319420
Some of the the permissible ARM -mfpu options, which are supported in GCC,
are currently not present in llvm/clang.This patch adds the options:
'neon-fp16', 'vfpv3-fp16', 'vfpv3-d16-fp16', 'vfpv3xd' and 'vfpv3xd-fp16.
These are related to half-precision floating-point and single precision.
Reviewers: rengolin, ranjeet.singh
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D10764
llvm-svn: 240929
The main effect of this is to fix anomalies where certain -mfpu options didn't
disable everything that they should causing strange behaviour when combined
with -mcpu or -march values that themselves enabled fpu subtarget features,
e.g. -mfpu=fpv5-dp-d16 with -march=armv7em previously behaved the same as
-mfpu=fpv5-sp-d16 due to fp-only-sp not being disabled.
Invalid -mfpu options now also give an error, which is consistent with the
handling of the .fpu directive.
Differential Revision: http://reviews.llvm.org/D10239
llvm-svn: 239152
This is a starting point for using the TargetParser in Clang, in a simple
enough part of the code that can be used without disrupting the crazy
platform support that we need to be compatible with other toolchains.
Also adding a few FIXME on obvious places that need replacing, but those
cases will indeed break a few of the platform assumptions, as arch/cpu names
change multiple times in the driver.
Finally, I'm changing the "neon-vfpv3" behaviour to match standard NEON, since
-mfpu=neon implies vfpv3 by default in both Clang and LLVM. That option
string is still supported as an alias to "neon".
llvm-svn: 236901
ARMv6K is another layer between ARMV6 and ARMV6T2. This is the Clang
side of the changes.
ARMV6 family LLVM implementation.
+-------------------------------------+
| ARMV6 |
+----------------+--------------------+
| ARMV6M (thumb) | ARMV6K (arm,thumb) | <- From ARMV6K and ARMV6M processors
+----------------+--------------------+ have support for hint instructions
| ARMV6T2 (arm,thumb,thumb2) | (SEV/WFE/WFI/NOP/YIELD). They can
+-------------------------------------+ be either real or default to NOP.
| ARMV7 (arm,thumb,thumb2) | The two processors also use
+-------------------------------------+ different encoding for them.
Patch by Vinicius Tinti.
llvm-svn: 232469
Add neon-vfpv3 to allow specifying both at the same time. This is not an
option that GCC supports, but follows the same track and should be
non-controversial.
Change-Id: Id9ec157c835937d7d11ad0f49dbe5171fac17658
llvm-svn: 222933
Summary: The changes introduced in the above two commits are giving
a rough time to one of the build bots. Reverting the changes for the
moment so that the bot can go green again.
Change-Id: Id19f6cb2a8bc292631fac2262268927563d820c2
llvm-svn: 218970
The Cortex-M7 has 3 options for its FPU: none, FPv5-SP-D16 and
FPv5-DP-D16. FPv5 has the same instructions as FP-ARMv8, so it can be
modeled using the same target feature, and all double-precision
operations are already disabled by the fp-only-sp target features.
llvm-svn: 218748
Added two new options for -mfpu when targetting ARM:
* fpv4-sp-d16
* fp4-sp-d16
The first is the same spelling as gcc.
The lack of a leading `v' is correct, this is consistent with ARM's
documentation and gcc's spelling of the option.
llvm-svn: 201846
Although we wire up a bit for v8fp for macro setting
purposes, we don't set a macro yet. Need to ask list
about that.
Change-Id: Ic9819593ce00882fbec72757ffccc6f0b18160a0
llvm-svn: 193367
- Support gcc-compatible vfpv3 name in addition to vfp3.
- Support vfpv3-d16.
- Disable neon feature for -mfpu=vfp* (yes, we were emitting Neon instructions
for those!).
llvm-svn: 147943
Momchil Velikov