With constant-sharing, litpool loads consume 4 + N*2 bytes of code, but
movw/movt pairs consume 8*N. This means litpools are better than movw/movt even
with just one use. Other materialisation strategies can still be better though,
so the logic is a little odd.
llvm-svn: 199891
The ARM backend has been using most of the MachO related subtarget
checks almost interchangeably, and since the only target it's had to
run on has been IOS (which is all three of MachO, Darwin and IOS) it's
worked out OK so far.
But we'd like to support embedded targets under the "*-*-none-macho"
triple, which means everything starts falling apart and inconsistent
behaviours emerge.
This patch should pick a reasonably sensible set of behaviours for the
new triple (and any others that come along, with luck). Some choices
were debatable (notably FP == r7 or r11), but we can revisit those
later when deficiencies become apparent.
llvm-svn: 198617
These are handled almost identically to static mode (and ELF's global address
materialisation), except that a symbol may have "$non_lazy_ptr" appended. This
can be handled by passing appropriate flags along with the instruction instead
of using entirely separate pseudo-instructions.
llvm-svn: 195655
There is no sane way for an LEApcrel (= single ADR) instruction to generate a
global address on any ARM target I know of. Fortunately, no-one was trying to
any more, but there were vestigial patterns.
llvm-svn: 195644
Cortex-M0 supports these 32-bit instructions despite being Thumb1 only
(mostly). We knew about that but not that the aliases without the default "sy"
operand were also permitted.
llvm-svn: 194094
Adds a subtarget feature for the CRC instructions (optional in v8-A) to the ARM (32-bit) backend.
Differential Revision: http://llvm-reviews.chandlerc.com/D2036
llvm-svn: 193599
This function-attribute modifies the callee-saved register list and function
epilogue (specifically the return instruction) so that a routine is suitable
for use as an interrupt-handler of the specified type without disrupting
user-mode applications.
rdar://problem/14207019
llvm-svn: 191766
These were pretty straightforward instructions, with some assembly support
required for HLT.
The ARM assembler is keen to split the instruction mnemonic into a
(non-existent) 'H' instruction with the LT condition code. An exception for
HLT is needed.
HLT follows the same rules as BKPT when in IT blocks, so the special BKPT
hadling code has been adapted to handle HLT also.
Regression tests added including diagnostic tests for out of range immediates
and illegal condition codes, as well as negative tests for pre-ARMv8.
llvm-svn: 190053
Solution is not sufficient to prevent 'mov pc, lr' being emitted for jump table code.
Test case doesn't trigger the added functionality.
llvm-svn: 190047
This improves code generation for jump tables by avoiding the emission of "mov pc, lr" which could fool the processor into believing this is a return from a function causing mispredicts. The code generation logic for jump tables uses ADR to materialize the address of the jump target.
Patch by Daniel Stewart!
llvm-svn: 190043
Fix a few things in one swoop.
# Add some negative tests.
# Fix some formatting issues.
# Add some missing IsThumb / ARMv8
# Fix some outs / ins mistakes.
llvm-svn: 189490
Back in the mists of time (2008), it seems TableGen couldn't handle the
patterns necessary to match ARM's CMOV node that we convert select operations
to, so we wrote a lot of fairly hairy C++ to do it for us.
TableGen can deal with it now: there were a few minor differences to CodeGen
(see tests), but nothing obviously worse that I could see, so we should
probably address anything that *does* come up in a localised manner.
llvm-svn: 188995
According to the ARM specification, "mov" is a valid mnemonic for all Thumb2 MOV encodings.
To achieve this, the patch adds one instruction alias with a special range condition to avoid collision with the Thumb1 MOV.
llvm-svn: 188901
The Thumb2 add immediate is in fact defined for SP. The manual is misleading as it points to a different section for add immediate with SP, however the encoding is the same as for add immediate with register only with the SP operand hard coded. As such add immediate with SP and add immediate with register can safely be treated as the same instruction.
All the patch does is adjust a register constraint on an instruction alias.
llvm-svn: 188676
There are many Thumb instructions which take 12-bit immediates encoded in a special
8-byte value + 4-byte rotator form. Not all numbers are represented, and it's legal
to transform an assembly instruction to be able to encode the immediate.
For example: AND and BIC are complementary instructions; one can switch the AND
to a BIC as long as the immediate is complemented.
The intent is to switch one instruction into its complementary one when the immediate
cannot be encoded in the form requested in the original assembly and when the
complementary immediate is encodable.
The patch addresses two issues:
1. definition of t2SOImmNot immediate - it has to check that the orignal value is
not encoded naturally
2. t2AND and t2BIC instruction aliases which should use the Thumb2 SOImm operand
rather than the ARM one.
llvm-svn: 188548
1. The offset range for Thumb1 PC relative loads is [0..1020] and not [-1024..1020]
2. Thumb2 PC relative loads may define the PC, so the restriction placed on target register is removed
3. Removes unneeded alias between "ldr.n" and t1LDRpci. ".n" is actually stripped by both tablegen
and the ASM parser, so this alias rule really does nothing
llvm-svn: 188466
In Thumb1, only one variant is supported: CPS{effect} {flags}
Thumb2 supports three:
CPS{effect}.W {flags}
CPS{effect} {flags} {mode}
CPS {mode}
Canonically, .W should be used only when ambiguity is present between encodings of different width.
The wide suffix is still accepted for the latter two forms via aliases.
llvm-svn: 188071
The long encoding for Thumb2 unconditional branches is broken.
Additionally, there is no range checking for target operands; as such
for instructions originating in assembly code, only short Thumb encodings
are generated, regardless of the bitsize needed for the offset.
Adding range checking is non trivial due to the representation of Thumb
branch instructions. There is no true difference between conditional and
unconditional branches in terms of operands and syntax - even unconditional
branches have a predicate which is expected to match that of the IT block
they are in. Yet, the encodings and the permitted size of the offset differ.
Due to this, for any mnemonic there are really 4 encodings to choose for.
The problem cannot be handled in the parser alone or by manipulating td files.
Because the parser builds first a set of match candidates and then checks them
one by one, whatever tablegen-only solution might be found will ultimately be
dependent of the parser's evaluation order. What's worse is that due to the fact
that all branches have the same syntax and the same kinds of operands, that
order is governed by the lexicographical ordering of the names of operand
classes...
To circumvent all this, any necessary disambiguation is added to the instruction
validation pass.
llvm-svn: 188067
This is the only Thumb2 instruction defined with "t" prefix; all other Thumb2 instructions have "t2" prefix (e.g. "t2CDP2" which is defined immediately afterwards).
Patch by Artyom Skrobov.
llvm-svn: 187973
While the .td entry is nice and all, it takes a pretty gross hack in
ARMAsmParser::ParseInstruction() because of handling of other "subs"
instructions to get it to match. Ran it by Jim Grosbach and he said it was
about what he expected to make this work given the existing code.
rdar://14214063
llvm-svn: 187530
instructions. With this patch:
1. ldr.n is recognized as mnemonic for the short encoding
2. ldr.w is recognized as menmonic for the long encoding
3. ldr will map to either short or long encodings depending on the size of the offset
llvm-svn: 186831
After Ulrich's r180677 (thanks!) TableGen is intelligent enough to
handle tied constraints involving complex operands properly, so
virtually all of the ARM custom converters are now unnecessary.
llvm-svn: 186810
This adds an instruction alias to make the assembler recognize the alternate literal form: pli [PC, #+/-<imm>]
See A8.8.129 in the ARM ARM (DDI 0406C.b).
Fixes <rdar://problem/14403733>.
llvm-svn: 186459
Propagate the fix from r185712 to Thumb2 codegen as well. Original
commit message applies here as well:
A "pkhtb x, x, y asr #num" uses the lower 16 bits of "y asr #num" and
packs them in the bottom half of "x". An arithmetic and logic shift are
only equivalent in this context if the shift amount is 16. We would be
shifting in ones into the bottom 16bits instead of zeros if "y" is
negative.
rdar://14338767
llvm-svn: 185982
1. it should accept only 4-byte aligned addresses
2. the maximum offset should be 1020
3. it should be encoded with the offset scaled by two bits
llvm-svn: 185528
Unfortunately this addresses two issues (by the time I'd disentangled the logic
it wasn't worth putting it back to half-broken):
+ Coprocessor instructions should all be predicable in Thumb mode.
+ BKPT should never be predicable.
llvm-svn: 184965
When using a positive offset, literal loads where encoded
as if it was negative, because:
- The sign bit was not assigned to an operand
- The addrmode_imm12 operand was not encoding the sign bit correctly
This patch also makes the assembler look at the .w/.n specifier for
loads.
llvm-svn: 184182
Tim Northover