Commit Graph

56 Commits

Author SHA1 Message Date
Quentin Colombet
0df68423f9 [Peephole] Rewrite copies to avoid cross register banks copies.
By definition copies across register banks are not coalescable. Still, it may be
possible to get rid of such a copy when the value is available in another
register of the same register file.
Consider the following example, where capital and lower letters denote different
register file:
b = copy A <-- cross-bank copy
...
C = copy b <-- cross-bank copy

This could have been optimized this way:
b = copy A  <-- cross-bank copy
...
C = copy A <-- same-bank copy

Note: b and C's definitions may be in different basic blocks.

This patch adds a peephole optimization that looks through a chain of copies
leading to a cross-bank copy and reuses a source that is on the same register
file if available.

This solution could also be used to get rid of some copies (e.g., A could have
been used instead of C). However, we do not do so because:
- It may over constrain the coloring of the source register for coalescing.
- The register allocator may not be able to find a nice split point for the
  longer live-range, leading to more spill.

<rdar://problem/14742333>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190713 91177308-0d34-0410-b5e6-96231b3b80d8
2013-09-13 18:26:31 +00:00
Craig Topper
a1032b7e4c Add debug prints for when optimizeLoadInstr folds a load.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170298 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-17 03:56:00 +00:00
Joel Jones
8293b7b8b1 Add comment for load folding
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169880 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-11 16:10:25 +00:00
Chandler Carruth
d04a8d4b33 Use the new script to sort the includes of every file under lib.
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.

Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169131 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03 16:50:05 +00:00
Rafael Espindola
10ad98bbbb Make sure we iterate over newly created instructions. Fixes pr13625. Testcase to
follow in one sec.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165951 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 18:21:07 +00:00
Jakob Stoklund Olesen
cabc0699ea Use standard pattern for iterate+erase.
Increment the MBB iterator at the top of the loop to properly handle the
current (and previous) instructions getting erased.

This fixes PR13625.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162099 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-17 14:38:59 +00:00
Jakob Stoklund Olesen
f2c64ef519 Add an MCID::Select flag and TII hooks for optimizing selects.
Select instructions pick one of two virtual registers based on a
condition, like x86 cmov. On targets like ARM that support predication,
selects can sometimes be eliminated by predicating the instruction
defining one of the operands.

Teach PeepholeOptimizer to recognize select instructions, and ask the
target to optimize them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162059 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-16 23:11:47 +00:00
Manman Ren
127eea87d6 X86 Peephole: fold loads to the source register operand if possible.
Add more comments and use early returns to reduce nesting in isLoadFoldable.
Also disable folding for V_SET0 to avoid introducing a const pool entry and
a const pool load.

rdar://10554090 and rdar://11873276


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161207 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-02 19:37:32 +00:00
Manman Ren
d7d003c2b7 X86 Peephole: fold loads to the source register operand if possible.
Machine CSE and other optimizations can remove instructions so folding
is possible at peephole while not possible at ISel.

This patch is a rework of r160919 and was tested on clang self-host on my local
machine.

rdar://10554090 and rdar://11873276


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161152 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-02 00:56:42 +00:00
Manman Ren
e8b4a4a9d1 Revert r160920 and r160919 due to dragonegg and clang selfhost failure
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160927 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-29 02:44:09 +00:00
Manman Ren
0eb3edea9c X86 Peephole: fold loads to the source register operand if possible.
Machine CSE and other optimizations can remove instructions so folding
is possible at peephole while not possible at ISel.

rdar://10554090 and rdar://11873276


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160919 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-28 16:48:01 +00:00
Manman Ren
de7266c611 Add SrcReg2 to analyzeCompare and optimizeCompareInstr to handle Compare
instructions with two register operands.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159465 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-29 21:33:59 +00:00
Jakob Stoklund Olesen
7164288c3e Implement PPCInstrInfo::isCoalescableExtInstr().
The PPC::EXTSW instruction preserves the low 32 bits of its input, just
like some of the x86 instructions. Use it to reduce register pressure
when the low 32 bits have multiple uses.

This requires a small change to PeepholeOptimizer since EXTSW takes a
64-bit input register.

This is related to PR5997.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158743 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-19 21:14:34 +00:00
Jakob Stoklund Olesen
d8d0279c00 Style: Don't reuse variables for multiple purposes.
No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158742 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-19 21:10:18 +00:00
Manman Ren
2afde7782d Revert r157755.
The commit is intended to fix rdar://11540023.
It is implemented as part of peephole optimization. We can actually implement
this in the SelectionDAG lowering phase.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158122 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-06 23:53:03 +00:00
Manman Ren
91c5346d91 X86: replace SUB with CMP if possible
This patch will optimize the following
        movq    %rdi, %rax
        subq    %rsi, %rax
        cmovsq  %rsi, %rdi
        movq    %rdi, %rax
to
        cmpq    %rsi, %rdi
        cmovsq  %rsi, %rdi
        movq    %rdi, %rax

Perform this optimization if the actual result of SUB is not used.

rdar: 11540023


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157755 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-31 17:20:29 +00:00
Jakob Stoklund Olesen
418a3638ac Constrain regclasses in PeepholeOptimizer.
It can be necessary to restrict to a sub-class before accessing
sub-registers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157164 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-20 18:42:55 +00:00
Manman Ren
247c5ab07c ARM: peephole optimization to remove cmp instruction
This patch will optimize the following cases:
  sub r1, r3 | sub r1, imm
  cmp r3, r1 or cmp r1, r3 | cmp r1, imm
  bge L1

TO
  subs r1, r3
  bge  L1 or ble L1

If the branch instruction can use flag from "sub", then we can replace
"sub" with "subs" and eliminate the "cmp" instruction.

rdar: 10734411


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156599 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-11 01:30:47 +00:00
Manman Ren
fe65d98dad Revert: 156550 "ARM: peephole optimization to remove cmp instruction"
This commit broke an external linux bot and gave a compile-time warning.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156556 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-10 18:49:43 +00:00
Manman Ren
8ae4f062e4 ARM: peephole optimization to remove cmp instruction
This patch will optimize the following cases:
  sub r1, r3 | sub r1, imm
  cmp r3, r1 or cmp r1, r3 | cmp r1, imm
  bge L1

TO
  subs r1, r3
  bge  L1 or ble L1

If the branch instruction can use flag from "sub", then we can replace
"sub" with "subs" and eliminate the "cmp" instruction.

rdar: 10734411


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156550 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-10 16:48:21 +00:00
Jim Grosbach
39cc513870 Tidy up. Naming conventions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155960 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-01 23:21:41 +00:00
Lang Hames
c69cbd0a74 Make the peephole optimizer clear kill flags on a vreg if it's about to add new
uses of the vreg, since the old kills may no longer be valid.  This was causing
-verify-machineinstrs to complain about uses after kills, and could potentially
have been causing subtle register allocation issues, but I haven't come across a
test case yet.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151425 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-25 02:01:00 +00:00
Lang Hames
3b26eb6294 Fixed typo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151417 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-25 00:46:38 +00:00
Andrew Trick
1dd8c8560d Codegen pass definition cleanup. No functionality.
Moving toward a uniform style of pass definition to allow easier target configuration.
Globally declare Pass ID.
Globally declare pass initializer.
Use INITIALIZE_PASS consistently.
Add a call to the initializer from CodeGen.cpp.
Remove redundant "createPass" functions and "getPassName" methods.

While cleaning up declarations, cleaned up comments (sorry for large diff).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150100 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-08 21:23:13 +00:00
Andrew Trick
1df91b0e54 whitespace
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150094 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-08 21:22:43 +00:00
Evan Cheng
5a96b3dad2 Add bundle aware API for querying instruction properties and switch the code
generator to it. For non-bundle instructions, these behave exactly the same
as the MC layer API.

For properties like mayLoad / mayStore, look into the bundle and if any of the
bundled instructions has the property it would return true.
For properties like isPredicable, only return true if *all* of the bundled
instructions have the property.
For properties like canFoldAsLoad, isCompare, conservatively return false for
bundles.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146026 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-07 07:15:52 +00:00
Nick Lewycky
dec1b10161 If MI is deleted then remove it from the set. If a new MI is created, it could
have the same address as the one we deleted, and we don't want that in the set
yet. Noticed by inspection.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141849 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-13 02:16:18 +00:00
Duncan Sands
7becbc41ab SrcDef is only written and never read. Remove it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136080 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-26 15:05:06 +00:00
Evan Cheng
e837dead3c - Rename TargetInstrDesc, TargetOperandInfo to MCInstrDesc and MCOperandInfo and
sink them into MC layer.
- Added MCInstrInfo, which captures the tablegen generated static data. Chang
TargetInstrInfo so it's based off MCInstrInfo.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134021 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-28 19:10:37 +00:00
Evan Cheng
d158fba3e4 Add a peephole optimization to optimize pairs of bitcasts. e.g.
v2 = bitcast v1
...
v3 = bitcast v2
...
   = v3
=>
v2 = bitcast v1
...
   = v1
if v1 and v3 are of in the same register class.

bitcast between i32 and fp (and others) are often not nops since they
are in different register classes. These bitcast instructions are often
left because they are in different basic blocks and cannot be
eliminated by dag combine.

rdar://9104514


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127668 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-15 05:13:13 +00:00
Evan Cheng
326d976eb2 Fix thinko. Cmp can be the first instruction in a MBB.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125552 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-15 05:00:24 +00:00
Evan Cheng
cf75ab5975 Fix PR8854. Track inserted copies to avoid read before write. Sorry, it's hard to reduce a sensible small test case.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125523 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-14 21:50:37 +00:00
Jakob Stoklund Olesen
c9df025e33 Simplify a bunch of isVirtualRegister() and isPhysicalRegister() logic.
These functions not longer assert when passed 0, but simply return false instead.

No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123155 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-10 02:58:51 +00:00
Evan Cheng
c36b7069b4 Do not model all INLINEASM instructions as having unmodelled side effects.
Instead encode llvm IR level property "HasSideEffects" in an operand (shared
with IsAlignStack). Added MachineInstrs::hasUnmodeledSideEffects() to check
the operand when the instruction is an INLINEASM.

This allows memory instructions to be moved around INLINEASM instructions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123044 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-07 23:50:32 +00:00
Evan Cheng
30a343aeed DBG_VALUE does not have any side effects; it also makes no sense to mark it cheap as a copy.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123031 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-07 21:08:26 +00:00
Evan Cheng
c4af4638df Remove ARM isel hacks that fold large immediates into a pair of add, sub, and,
and xor. The 32-bit move immediates can be hoisted out of loops by machine
LICM but the isel hacks were preventing them.

Instead, let peephole optimization pass recognize registers that are defined by
immediates and the ARM target hook will fold the immediates in.

Other changes include 1) do not fold and / xor into cmp to isel TST / TEQ
instructions if there are multiple uses. This happens when the 'and' is live
out, machine sink would have sinked the computation and that ends up pessimizing
code. The peephole pass would recognize situations where the 'and' can be
toggled to define CPSR and eliminate the comparison anyway.

2) Move peephole pass to after machine LICM, sink, and CSE to avoid blocking
important optimizations.

rdar://8663787, rdar://8241368


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119548 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-17 20:13:28 +00:00
Evan Cheng
eb96a2f6c0 Code clean up. The peephole pass should be the one updating the instruction
iterator, not TII->OptimizeCompareInstr.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119186 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-15 21:20:45 +00:00
Bill Wendling
40a5eb18b0 When we look at instructions to convert to setting the 's' flag, we need to look
at more than those which define CPSR. You can have this situation:

(1)  subs  ...
(2)  sub   r6, r5, r4
(3)  movge ...
(4)  cmp   r6, 0
(5)  movge ...

We cannot convert (2) to "subs" because (3) is using the CPSR set by
(1). There's an analogous situation here:

(1)  sub   r1, r2, r3
(2)  sub   r4, r5, r6
(3)  cmp   r4, ...
(5)  movge ...
(6)  cmp   r1, ...
(7)  movge ...

We cannot convert (1) to "subs" because of the intervening use of CPSR.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117950 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-01 20:41:43 +00:00
Bill Wendling
9e7cb3d243 The testcase is now XFAILed. Sorry about the breakage.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117904 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-01 05:50:55 +00:00
Eric Christopher
b698a56dd4 Revert r117876 for now, it's causing more testsuite failures.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117879 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-31 22:42:55 +00:00
Bill Wendling
b3747706fc Disable the peephole optimizer until 186.crafty on armv6 is fixed. This is what
looks like is happening:

Without the peephole optimizer:
  (1)   sub     r6, r6, #32
        orr     r12, r12, lr, lsl r9
        orr     r2, r2, r3, lsl r10
  (x)   cmp     r6, #0
        ldr     r9, LCPI2_10
        ldr     r10, LCPI2_11
  (2)   sub     r8, r8, #32
  (a)   movge   r12, lr, lsr r6
  (y)   cmp     r8, #0
LPC2_10:
        ldr     lr, [pc, r10]
  (b)   movge   r2, r3, lsr r8

With the peephole optimizer:
        ldr     r9, LCPI2_10
        ldr     r10, LCPI2_11
  (1*)  subs    r6, r6, #32
  (2*)  subs    r8, r8, #32
  (a*)  movge   r12, lr, lsr r6
  (b*)  movge   r2, r3, lsr r8

(1) is used by (x) for the conditional move at (a). (2) is used by (y) for the
conditional move at (b). After the peephole optimizer, these the flags resulting
from (1*) are ignored and only the flags from (2*) are considered for both
conditional moves.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117876 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-31 22:07:12 +00:00
Owen Anderson
081c34b725 Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which
must be called in the pass's constructor.  This function uses static dependency declarations to recursively initialize
the pass's dependencies.

Clients that only create passes through the createFooPass() APIs will require no changes.  Clients that want to use the
CommandLine options for passes will need to manually call the appropriate initialization functions in PassInitialization.h
before parsing commandline arguments.

I have tested this with all standard configurations of clang and llvm-gcc on Darwin.  It is possible that there are problems
with the static dependencies that will only be visible with non-standard options.  If you encounter any crash in pass
registration/creation, please send the testcase to me directly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116820 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-19 17:21:58 +00:00
Bill Wendling
b41ee96d76 Don't recompute MachineRegisterInfo in the Optimize* method.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116750 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-18 21:22:31 +00:00
Owen Anderson
2ab36d3502 Begin adding static dependence information to passes, which will allow us to
perform initialization without static constructors AND without explicit initialization
by the client.  For the moment, passes are required to initialize both their
(potential) dependencies and any passes they preserve.  I hope to be able to relax
the latter requirement in the future.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116334 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-12 19:48:12 +00:00
Owen Anderson
ce665bd2e2 Now with fewer extraneous semicolons!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115996 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07 22:25:06 +00:00
Gabor Greif
04ac81d5db Move the search for the appropriate AND instruction
into OptimizeCompareInstr.
This necessitates the passing of CmpValue around,
so widen the virtual functions to accomodate.

No functionality changes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114428 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-21 12:01:15 +00:00
Gabor Greif
4f7d107d1d must not peephole away side effects
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113848 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-14 20:46:08 +00:00
Bill Wendling
a65568676d Rename ConvertToSetZeroFlag to something more general.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113670 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-11 00:13:50 +00:00
Bill Wendling
3665661a57 No need to recompute the SrcReg and CmpValue.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113666 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-10 23:46:12 +00:00
Bill Wendling
92ad57f066 Move some of the decision logic for converting an instruction into one that sets
the 'zero' bit down into the back-end. There are other cases where this logic
isn't sufficient, so they should be handled separately.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113665 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-10 23:34:19 +00:00