This patch assigns cost of the scaling used in addressing.
On many ARM cores, a negated register offset takes longer than a
non-negated register offset, in a register-offset addressing mode.
For instance:
LDR R0, [R1, R2 LSL #2]
LDR R0, [R1, -R2 LSL #2]
Above, (1) takes less cycles than (2).
By assigning appropriate scaling factor cost, we enable the LLVM
to make the right trade-offs in the optimization and code-selection phase.
Differential Revision: http://reviews.llvm.org/D24857
Reviewers: jmolloy, rengolin
llvm-svn: 284127
Currently, the Int_eh_sjlj_dispatchsetup intrinsic is marked as
clobbering all registers, including floating-point registers that may
not be present on the target. This is technically true, as we could get
linked against code that does use the FP registers, but that will not
actually work, as the soft-float code cannot save and restore the FP
registers. SjLj exception handling can only work correctly if either all
or none of the code is built for a target with FP registers. Therefore,
we can assume that, when Int_eh_sjlj_dispatchsetup is compiled for a
soft-float target, it is only going to be linked against other
soft-float code, and so only clobbers the general-purpose registers.
This allows us to check that no non-savable registers are clobbered when
generating the prologue/epilogue.
Differential Revision: https://reviews.llvm.org/D25180
llvm-svn: 283866
Reapplying r283383 after revert in r283442. The additional fix
is a getting rid of a stray space in a function name, in the
refactoring part of the commit.
This avoids falling back to calling out to the GCC rem functions
(__moddi3, __umoddi3) when targeting Windows.
The __rt_div functions have flipped the two arguments compared
to the __aeabi_divmod functions. To match MSVC, we emit a
check for division by zero before actually calling the library
function (even if the library function itself also might do
the same check).
Not all calls to __rt_div functions for division are currently
merged with calls to the same function with the same parameters
for the remainder. This is more wasteful than a div + mls as before,
but avoids calls to __moddi3.
Differential Revision: https://reviews.llvm.org/D25332
llvm-svn: 283550
This reverts commit r283383 because it broke some of the bots:
undefined reference to ` __aeabi_uldivmod'
It affected (at least) clang-cmake-armv7-a15-selfhost,
clang-cmake-armv7-a15-selfhost and clang-native-arm-lnt.
llvm-svn: 283442
Global variables are GlobalValues, so they have explicit alignment. Querying
DataLayout for the alignment was incorrect.
Testcase added.
llvm-svn: 283423
This avoids falling back to calling out to the GCC rem functions
(__moddi3, __umoddi3) when targeting Windows.
The __rt_div functions have flipped the two arguments compared
to the __aeabi_divmod functions. To match MSVC, we emit a
check for division by zero before actually calling the library
function (even if the library function itself also might do
the same check).
Not all calls to __rt_div functions for division are currently
merged with calls to the same function with the same parameters
for the remainder. This is more wasteful than a div + mls as before,
but avoids calls to __moddi3.
Differential Revision: https://reviews.llvm.org/D24076
llvm-svn: 283383
library call to __aeabi_uidivmod. This is an improved implementation of
r280808, see also D24133, that got reverted because isel was stuck in a loop.
That was caused by the optimisation incorrectly triggering on i64 ints, which
shouldn't happen because there is no 64bit hwdiv support; that put isel's type
legalization and this optimisation in a loop. A native ARM compiler and testing
now shows that this is fixed.
Patch mostly by Pablo Barrio.
Differential Revision: https://reviews.llvm.org/D25077
llvm-svn: 283098
If a constant is unamed_addr and is only used within one function, we can save
on the code size and runtime cost of an indirection by changing the global's storage
to inside the constant pool. For example, instead of:
ldr r0, .CPI0
bl printf
bx lr
.CPI0: &format_string
format_string: .asciz "hello, world!\n"
We can emit:
adr r0, .CPI0
bl printf
bx lr
.CPI0: .asciz "hello, world!\n"
This can cause significant code size savings when many small strings are used in one
function (4 bytes per string).
This recommit contains fixes for a nasty bug related to fast-isel fallback - because
fast-isel doesn't know about this optimization, if it runs and emits references to
a string that we inline (because fast-isel fell back to SDAG) we will end up
with an inlined string and also an out-of-line string, and we won't emit the
out-of-line string, causing backend failures.
It also contains fixes for emitting .text relocations which made the sanitizer
bots unhappy.
llvm-svn: 282387
If a constant is unamed_addr and is only used within one function, we can save
on the code size and runtime cost of an indirection by changing the global's storage
to inside the constant pool. For example, instead of:
ldr r0, .CPI0
bl printf
bx lr
.CPI0: &format_string
format_string: .asciz "hello, world!\n"
We can emit:
adr r0, .CPI0
bl printf
bx lr
.CPI0: .asciz "hello, world!\n"
This can cause significant code size savings when many small strings are used in one
function (4 bytes per string).
This recommit contains fixes for a nasty bug related to fast-isel fallback - because
fast-isel doesn't know about this optimization, if it runs and emits references to
a string that we inline (because fast-isel fell back to SDAG) we will end up
with an inlined string and also an out-of-line string, and we won't emit the
out-of-line string, causing backend failures.
It also contains fixes for emitting .text relocations which made the sanitizer
bots unhappy.
llvm-svn: 282241
(and the same for SREM)
This was causing buildbot failures earlier (time outs in the LNT suite).
However, we haven't been able to reproduce this and are suspecting this
was caused by another (reverted) patch.
llvm-svn: 281719
If a constant is unamed_addr and is only used within one function, we can save
on the code size and runtime cost of an indirection by changing the global's storage
to inside the constant pool. For example, instead of:
ldr r0, .CPI0
bl printf
bx lr
.CPI0: &format_string
format_string: .asciz "hello, world!\n"
We can emit:
adr r0, .CPI0
bl printf
bx lr
.CPI0: .asciz "hello, world!\n"
This can cause significant code size savings when many small strings are used in one
function (4 bytes per string).
This recommit contains fixes for a nasty bug related to fast-isel fallback - because
fast-isel doesn't know about this optimization, if it runs and emits references to
a string that we inline (because fast-isel fell back to SDAG) we will end up
with an inlined string and also an out-of-line string, and we won't emit the
out-of-line string, causing backend failures.
It also contains fixes for emitting .text relocations which made the sanitizer
bots unhappy.
llvm-svn: 281715
If a constant is unamed_addr and is only used within one function, we can save
on the code size and runtime cost of an indirection by changing the global's storage
to inside the constant pool. For example, instead of:
ldr r0, .CPI0
bl printf
bx lr
.CPI0: &format_string
format_string: .asciz "hello, world!\n"
We can emit:
adr r0, .CPI0
bl printf
bx lr
.CPI0: .asciz "hello, world!\n"
This can cause significant code size savings when many small strings are used in one
function (4 bytes per string).
This recommit contains fixes for a nasty bug related to fast-isel fallback - because
fast-isel doesn't know about this optimization, if it runs and emits references to
a string that we inline (because fast-isel fell back to SDAG) we will end up
with an inlined string and also an out-of-line string, and we won't emit the
out-of-line string, causing backend failures.
llvm-svn: 281604
If a constant is unamed_addr and is only used within one function, we can save
on the code size and runtime cost of an indirection by changing the global's storage
to inside the constant pool. For example, instead of:
ldr r0, .CPI0
bl printf
bx lr
.CPI0: &format_string
format_string: .asciz "hello, world!\n"
We can emit:
adr r0, .CPI0
bl printf
bx lr
.CPI0: .asciz "hello, world!\n"
This can cause significant code size savings when many small strings are used in one
function (4 bytes per string).
llvm-svn: 281484
If a constant is unamed_addr and is only used within one function, we can save
on the code size and runtime cost of an indirection by changing the global's storage
to inside the constant pool. For example, instead of:
ldr r0, .CPI0
bl printf
bx lr
.CPI0: &format_string
format_string: .asciz "hello, world!\n"
We can emit:
adr r0, .CPI0
bl printf
bx lr
.CPI0: .asciz "hello, world!\n"
This can cause significant code size savings when many small strings are used in one
function (4 bytes per string).
llvm-svn: 281314
If a constant is unamed_addr and is only used within one function, we can save
on the code size and runtime cost of an indirection by changing the global's storage
to inside the constant pool. For example, instead of:
ldr r0, .CPI0
bl printf
bx lr
.CPI0: &format_string
format_string: .asciz "hello, world!\n"
We can emit:
adr r0, .CPI0
bl printf
bx lr
.CPI0: .asciz "hello, world!\n"
This can cause significant code size savings when many small strings are used in one
function (4 bytes per string).
llvm-svn: 281213
Summary:
An IR load can be invariant, dereferenceable, neither, or both. But
currently, MI's notion of invariance is IR-invariant &&
IR-dereferenceable.
This patch splits up the notions of invariance and dereferenceability at
the MI level. It's NFC, so adds some probably-unnecessary
"is-dereferenceable" checks, which we can remove later if desired.
Reviewers: chandlerc, tstellarAMD
Subscribers: jholewinski, arsenm, nemanjai, llvm-commits
Differential Revision: https://reviews.llvm.org/D23371
llvm-svn: 281151
Move the target specific setup into the target specific lowering setup. As
pointed out by Anton, the initial change was moving this too high up the stack
resulting in a violation of the layering (the target generic code path setup
target specific bits). Sink this into the ARM specific setup. NFC.
llvm-svn: 281088
This reverts commit r280808.
It is possible that this change results in an infinite loop. This
is causing timeouts in some tests on ARM, and a Chromebook bot is
failing.
llvm-svn: 280918
Summary:
This saves a library call to __aeabi_uidivmod. However, the
processor must feature hardware division in order to benefit from
the transformation.
Reviewers: scott-0, jmolloy, compnerd, rengolin
Subscribers: t.p.northover, compnerd, aemerson, rengolin, samparker, llvm-commits
Differential Revision: https://reviews.llvm.org/D24133
llvm-svn: 280808
This is a mechanical change of comments in switches like fallthrough,
fall-through, or fall-thru to use the LLVM_FALLTHROUGH macro instead.
llvm-svn: 278902
This patch adds support for some new relocation models to the ARM
backend:
* Read-only position independence (ROPI): Code and read-only data is accessed
PC-relative. The offsets between all code and RO data sections are known at
static link time. This does not affect read-write data.
* Read-write position independence (RWPI): Read-write data is accessed relative
to the static base register (r9). The offsets between all writeable data
sections are known at static link time. This does not affect read-only data.
These two modes are independent (they specify how different objects
should be addressed), so they can be used individually or together. They
are otherwise the same as the "static" relocation model, and are not
compatible with SysV-style PIC using a global offset table.
These modes are normally used by bare-metal systems or systems with
small real-time operating systems. They are designed to avoid the need
for a dynamic linker, the only initialisation required is setting r9 to
an appropriate value for RWPI code.
I have only added support to SelectionDAG, not FastISel, because
FastISel is currently disabled for bare-metal targets where these modes
would be used.
Differential Revision: https://reviews.llvm.org/D23195
llvm-svn: 278015
Summary:
Commit 276701 requires that targets have the DSP extensions to use
certain saturating instructions. This requires some corrections.
For ARM ISA the instructions in question are available in all v6*
architectures.
For Thumb2, the instructions in question are available from v6T2.
SSAT and USAT are part of the base architecture while SSAT16 and
USAT16 require the DSP extensions.
Reviewers: rengolin
Subscribers: aemerson, rengolin, samparker, llvm-commits
Differential Revision: https://reviews.llvm.org/D23010
llvm-svn: 277439
Summary:
The MOV/MOVT instructions being chosen for struct_byval predicates was
conditional only on Thumb2, resulting in an ARM MOV/MOVT instruction
being incorrectly emitted in Thumb1 mode. This is especially apparent
with v8-m.base targets. This patch ensures that Thumb instructions are
emitted in both Thumb modes.
Reviewers: rengolin, t.p.northover
Subscribers: llvm-commits, aemerson, rengolin
Differential Revision: https://reviews.llvm.org/D22865
llvm-svn: 277128
The saturation instructions appeared in v6T2, with DSP extensions, but they
were being accepted / generated on any, with the new introduction of the
saturation detection in the back-end. This commit restricts the usage to
DSP-enable only cores.
Fixes PR28607.
llvm-svn: 276701
Inference of the 'returned' attribute was fixed in r276008, lets try
turning the backend support back on.
This reverts commit r275677.
llvm-svn: 276081
At higher optimization levels, we generate the libcall for DIVREM_Ix, which is
fine: aeabi_{u|i}divmod. At -O0 we generate the one for REM_Ix, which is the
default {u}mod{q|h|s|d}i3.
This commit makes sure that we don't generate REM_Ix calls for ABIs that
don't support them (i.e. where we need to use DIVREM_Ix instead). This is
achieved by bailing out of FastISel, which can't handle non-double multi-reg
returns, and letting the legalization infrastructure expand the REM_Ix calls.
It also updates the divmod-eabi.ll test to run under -O0 as well, and adds some
Windows checks to it to make sure we don't break things for it.
Fixes PR27068
Differential Revision: https://reviews.llvm.org/D21926
llvm-svn: 275773
r275042 reverted function-attribute inference for the 'returned' attribute
because the feature triggered self-hosting failures on ARM and AArch64. James
Molloy determined that the this-return argument forwarding feature, which
directly ties the returned input argument to the returned value, was the cause.
It seems likely that this forwarding code contains, or triggers, a subtle bug.
Disabling for now until we can track that down.
llvm-svn: 275677
Summary:
Instead, we take a single flags arg (a bitset).
Also add a default 0 alignment, and change the order of arguments so the
alignment comes before the flags.
This greatly simplifies many callsites, and fixes a bug in
AMDGPUISelLowering, wherein the order of the args to getLoad was
inverted. It also greatly simplifies the process of adding another flag
to getLoad.
Reviewers: chandlerc, tstellarAMD
Subscribers: jholewinski, arsenm, jyknight, dsanders, nemanjai, llvm-commits
Differential Revision: http://reviews.llvm.org/D22249
llvm-svn: 275592
Thumb-1 doesn't have post-inc or pre-inc load or store instructions. However the LDM/STM instructions with writeback can function as post-inc load/store:
ldm r0!, {r1} @ load from r0 into r1 and increment r0 by 4
Obviously, this only works if the post increment is 4.
llvm-svn: 275540
... When we emit several calls to the same function in the same basic block.
An indirect call uses a "BLX r0" instruction which has a 16-bit encoding. If many calls are made to the same target, this can enable significant code size reductions.
llvm-svn: 275537
