Commit Graph

18 Commits

Author SHA1 Message Date
Francis Visoiu Mistrih 25528d6de7 [CodeGen] Unify MBB reference format in both MIR and debug output
As part of the unification of the debug format and the MIR format, print
MBB references as '%bb.5'.

The MIR printer prints the IR name of a MBB only for block definitions.

* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#" << ([a-zA-Z0-9_]+)->getNumber\(\)/" << printMBBReference(*\1)/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#" << ([a-zA-Z0-9_]+)\.getNumber\(\)/" << printMBBReference(\1)/g'
* find . \( -name "*.txt" -o -name "*.s" -o -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#([0-9]+)/%bb.\1/g'
* grep -nr 'BB#' and fix

Differential Revision: https://reviews.llvm.org/D40422

llvm-svn: 319665
2017-12-04 17:18:51 +00:00
Kyle Butt b15c06677c CodeGen: Allow small copyable blocks to "break" the CFG.
When choosing the best successor for a block, ordinarily we would have preferred
a block that preserves the CFG unless there is a strong probability the other
direction. For small blocks that can be duplicated we now skip that requirement
as well, subject to some simple frequency calculations.

Differential Revision: https://reviews.llvm.org/D28583

llvm-svn: 293716
2017-01-31 23:48:32 +00:00
Kyle Butt efe56fed12 Revert "CodeGen: Allow small copyable blocks to "break" the CFG."
This reverts commit ada6595a526d71df04988eb0a4b4fe84df398ded.

This needs a simple probability check because there are some cases where it is
not profitable.

llvm-svn: 291695
2017-01-11 19:55:19 +00:00
Kyle Butt df27aa8c89 CodeGen: Allow small copyable blocks to "break" the CFG.
When choosing the best successor for a block, ordinarily we would have preferred
a block that preserves the CFG unless there is a strong probability the other
direction. For small blocks that can be duplicated we now skip that requirement
as well.

Differential revision: https://reviews.llvm.org/D27742

llvm-svn: 291609
2017-01-10 23:04:30 +00:00
Peter Collingbourne 86b9fbe980 ARM: Better codegen for 64-bit compares.
This introduces a custom lowering for ISD::SETCCE (introduced in r253572)
that allows us to emit a short code sequence for 64-bit compares.

Before:

	push	{r7, lr}
	cmp	r0, r2
	mov.w	r0, #0
	mov.w	r12, #0
	it	hs
	movhs	r0, #1
	cmp	r1, r3
	it	ge
	movge.w	r12, #1
	it	eq
	moveq	r12, r0
	cmp.w	r12, #0
	bne	.LBB1_2
@ BB#1:                                 @ %bb1
	bl	f
	pop	{r7, pc}
.LBB1_2:                                @ %bb2
	bl	g
	pop	{r7, pc}

After:

	push	{r7, lr}
	subs	r0, r0, r2
	sbcs.w	r0, r1, r3
	bge	.LBB1_2
@ BB#1:                                 @ %bb1
	bl	f
	pop	{r7, pc}
.LBB1_2:                                @ %bb2
	bl	g
	pop	{r7, pc}

Saves around 80KB in Chromium's libchrome.so.

Some notes on this patch:

- I don't much like the ARMISD::BRCOND and ARMISD::CMOV combines I
  introduced (nothing else needs them). However, they are necessary in
  order to avoid poor codegen, and they seem similar to existing combines
  in other backends (e.g. X86 combines (brcond (cmp (setcc Compare))) to
  (brcond Compare)).

- No support for Thumb-1. This is in principle possible, but we'd need
  to implement ARMISD::SUBE for Thumb-1.

Differential Revision: http://reviews.llvm.org/D15256

llvm-svn: 263962
2016-03-21 18:00:02 +00:00
Ahmed Bougacha 81616a72ea [ARM] Emit clrex in the expanded cmpxchg fail block.
ARM counterpart to r248291:

In the comparison failure block of a cmpxchg expansion, the initial
ldrex/ldxr will not be followed by a matching strex/stxr.
On ARM/AArch64, this unnecessarily ties up the execution monitor,
which might have a negative performance impact on some uarchs.

Instead, release the monitor in the failure block.
The clrex instruction was designed for this: use it.

Also see ARMARM v8-A B2.10.2:
"Exclusive access instructions and Shareable memory locations".

Differential Revision: http://reviews.llvm.org/D13033

llvm-svn: 248294
2015-09-22 17:22:58 +00:00
Matthias Braun 125c9f5f7b ARM: Thumb2 LDRD/STRD supports independent input/output regs
The existing code would unnecessarily break LDRD/STRD apart with
non-adjacent registers, on thumb2 this is not necessary.

Ideally on thumb2 we shouldn't match for ldrd/strd pre-regalloc anymore
as there is not reason to set register hints anymore, changing that is
something for a future patch however.

Differential Revision: http://reviews.llvm.org/D9694

Recommiting after the revert in r238821, the buildbot still failed with
the patch removed so there seems to be another reason for the breakage.

llvm-svn: 238935
2015-06-03 16:30:24 +00:00
Renato Golin 3a7bec86bd Revert "ARM: Thumb2 LDRD/STRD supports independent input/output regs"
This reverts commit r238795, as it broke the Thumb2 self-hosting buildbot.

Since self-hosting issues with Clang are hard to investigate, I'm taking the
liberty to revert now, so we can investigate it offline.

llvm-svn: 238821
2015-06-02 11:47:30 +00:00
Matthias Braun e20dc1cd3a ARM: Thumb2 LDRD/STRD supports independent input/output regs
The existing code would unnecessarily break LDRD/STRD apart with
non-adjacent registers, on thumb2 this is not necessary.

Ideally on thumb2 we shouldn't match for ldrd/strd pre-regalloc anymore
as there is not reason to set register hints anymore, changing that is
something for a future patch however.

Differential Revision: http://reviews.llvm.org/D9694

llvm-svn: 238795
2015-06-01 23:27:08 +00:00
David Blaikie a79ac14fa6 [opaque pointer type] Add textual IR support for explicit type parameter to load instruction
Essentially the same as the GEP change in r230786.

A similar migration script can be used to update test cases, though a few more
test case improvements/changes were required this time around: (r229269-r229278)

import fileinput
import sys
import re

pat = re.compile(r"((?:=|:|^)\s*load (?:atomic )?(?:volatile )?(.*?))(| addrspace\(\d+\) *)\*($| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$)")

for line in sys.stdin:
  sys.stdout.write(re.sub(pat, r"\1, \2\3*\4", line))

Reviewers: rafael, dexonsmith, grosser

Differential Revision: http://reviews.llvm.org/D7649

llvm-svn: 230794
2015-02-27 21:17:42 +00:00
Renato Golin b9887ef32a Improve handling of stack accesses in Thumb-1
Thumb-1 only allows SP-based LDR and STR to be word-sized, and SP-base LDR,
STR, and ADD only allow offsets that are a multiple of 4. Make some changes
to better make use of these instructions:

* Use word loads for anyext byte and halfword loads from the stack.
* Enforce 4-byte alignment on objects accessed in this way, to ensure that
  the offset is valid.
* Do the same for objects whose frame index is used, in order to avoid having
  to use more than one ADD to generate the frame index.
* Correct how many bits of offset we think AddrModeT1_s has.

Patch by John Brawn.

llvm-svn: 230496
2015-02-25 14:41:06 +00:00
Tim Northover 420a216817 IR: add "cmpxchg weak" variant to support permitted failure.
This commit adds a weak variant of the cmpxchg operation, as described
in C++11. A cmpxchg instruction with this modifier is permitted to
fail to store, even if the comparison indicated it should.

As a result, cmpxchg instructions must return a flag indicating
success in addition to their original iN value loaded. Thus, for
uniformity *all* cmpxchg instructions now return "{ iN, i1 }". The
second flag is 1 when the store succeeded.

At the DAG level, a new ATOMIC_CMP_SWAP_WITH_SUCCESS node has been
added as the natural representation for the new cmpxchg instructions.
It is a strong cmpxchg.

By default this gets Expanded to the existing ATOMIC_CMP_SWAP during
Legalization, so existing backends should see no change in behaviour.
If they wish to deal with the enhanced node instead, they can call
setOperationAction on it. Beware: as a node with 2 results, it cannot
be selected from TableGen.

Currently, no use is made of the extra information provided in this
patch. Test updates are almost entirely adapting the input IR to the
new scheme.

Summary for out of tree users:
------------------------------

+ Legacy Bitcode files are upgraded during read.
+ Legacy assembly IR files will be invalid.
+ Front-ends must adapt to different type for "cmpxchg".
+ Backends should be unaffected by default.

llvm-svn: 210903
2014-06-13 14:24:07 +00:00
Christian Pirker b5728191c2 ARM big endian function argument passing
llvm-svn: 208316
2014-05-08 14:06:24 +00:00
Tim Northover 01b4aa9437 ARM: tell LLVM about zext properties of ldrexb/ldrexh
Implementing this via ComputeMaskedBits has two advantages:
  + It actually works. DAGISel doesn't deal with the chains properly
    in the previous pattern-based solution, so they never trigger.
  + The information can be used in other DAG combines, as well as the
    trivial "get rid of truncs". For example if the trunc is in a
    different basic block.

rdar://problem/16227836

llvm-svn: 205540
2014-04-03 15:10:35 +00:00
Tim Northover 70450c59a4 ARM: skip cmpxchg failure barrier if ordering is monotonic.
The terminal barrier of a cmpxchg expansion will be either Acquire or
SequentiallyConsistent. In either case it can be skipped if the
operation has Monotonic requirements on failure.

rdar://problem/15996804

llvm-svn: 205535
2014-04-03 13:06:54 +00:00
Tim Northover c882eb0723 ARM: expand atomic ldrex/strex loops in IR
The previous situation where ATOMIC_LOAD_WHATEVER nodes were expanded
at MachineInstr emission time had grown to be extremely large and
involved, to account for the subtly different code needed for the
various flavours (8/16/32/64 bit, cmpxchg/add/minmax).

Moving this transformation into the IR clears up the code
substantially, and makes future optimisations much easier:

1. an atomicrmw followed by using the *new* value can be more
   efficient. As an IR pass, simple CSE could handle this
   efficiently.
2. Making use of cmpxchg success/failure orderings only has to be done
   in one (simpler) place.
3. The common "cmpxchg; did we store?" idiom can be exposed to
   optimisation.

I intend to gradually improve this situation within the ARM backend
and make sure there are no hidden issues before moving the code out
into CodeGen to be shared with (at least ARM64/AArch64, though I think
PPC & Mips could benefit too).

llvm-svn: 205525
2014-04-03 11:44:58 +00:00
Tim Northover e94a518a22 IR: add a second ordering operand to cmpxhg for failure
The syntax for "cmpxchg" should now look something like:

	cmpxchg i32* %addr, i32 42, i32 3 acquire monotonic

where the second ordering argument gives the required semantics in the case
that no exchange takes place. It should be no stronger than the first ordering
constraint and cannot be either "release" or "acq_rel" (since no store will
have taken place).

rdar://problem/15996804

llvm-svn: 203559
2014-03-11 10:48:52 +00:00
Amara Emerson b4ad2f396a [ARM] Use the load-acquire/store-release instructions optimally in AArch32.
Patch by Artyom Skrobov.

llvm-svn: 191428
2013-09-26 12:22:36 +00:00