Commit Graph

20 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
Kyle Butt 0846e56e63 Codegen: Tail-duplicate during placement.
The tail duplication pass uses an assumed layout when making duplication
decisions. This is fine, but passes up duplication opportunities that
may arise when blocks are outlined. Because we want the updated CFG to
affect subsequent placement decisions, this change must occur during
placement.

In order to achieve this goal, TailDuplicationPass is split into a
utility class, TailDuplicator, and the pass itself. The pass delegates
nearly everything to the TailDuplicator object, except for looping over
the blocks in a function. This allows the same code to be used for tail
duplication in both places.

This change, in concert with outlining optional branches, allows
triangle shaped code to perform much better, esepecially when the
taken/untaken branches are correlated, as it creates a second spine when
the tests are small enough.

Issue from previous rollback fixed, and a new test was added for that
case as well. Issue was worklist/scheduling/taildup issue in layout.

Issue from 2nd rollback fixed, with 2 additional tests. Issue was
tail merging/loop info/tail-duplication causing issue with loops that share
a header block.

Issue with early tail-duplication of blocks that branch to a fallthrough
predecessor fixed with test case: tail-dup-branch-to-fallthrough.ll

Differential revision: https://reviews.llvm.org/D18226

llvm-svn: 283934
2016-10-11 20:36:43 +00:00
Daniel Jasper 0c42dc4784 Revert "Codegen: Tail-duplicate during placement."
This reverts commit r283842.

test/CodeGen/X86/tail-dup-repeat.ll causes and llc crash with our
internal testing. I'll share a link with you.

llvm-svn: 283857
2016-10-11 07:36:11 +00:00
Kyle Butt ae068a320c Codegen: Tail-duplicate during placement.
The tail duplication pass uses an assumed layout when making duplication
decisions. This is fine, but passes up duplication opportunities that
may arise when blocks are outlined. Because we want the updated CFG to
affect subsequent placement decisions, this change must occur during
placement.

In order to achieve this goal, TailDuplicationPass is split into a
utility class, TailDuplicator, and the pass itself. The pass delegates
nearly everything to the TailDuplicator object, except for looping over
the blocks in a function. This allows the same code to be used for tail
duplication in both places.

This change, in concert with outlining optional branches, allows
triangle shaped code to perform much better, esepecially when the
taken/untaken branches are correlated, as it creates a second spine when
the tests are small enough.

Issue from previous rollback fixed, and a new test was added for that
case as well. Issue was worklist/scheduling/taildup issue in layout.

Issue from 2nd rollback fixed, with 2 additional tests. Issue was
tail merging/loop info/tail-duplication causing issue with loops that share
a header block.

Issue with early tail-duplication of blocks that branch to a fallthrough
predecessor fixed with test case: tail-dup-branch-to-fallthrough.ll

Differential revision: https://reviews.llvm.org/D18226

llvm-svn: 283842
2016-10-11 01:20:33 +00:00
Kyle Butt 2facd194a2 Revert "Codegen: Tail-duplicate during placement."
This reverts commit 71c312652c10f1855b28d06697c08d47e7a243e4.

llvm-svn: 283647
2016-10-08 01:47:05 +00:00
Kyle Butt 37e676d857 Codegen: Tail-duplicate during placement.
The tail duplication pass uses an assumed layout when making duplication
decisions. This is fine, but passes up duplication opportunities that
may arise when blocks are outlined. Because we want the updated CFG to
affect subsequent placement decisions, this change must occur during
placement.

In order to achieve this goal, TailDuplicationPass is split into a
utility class, TailDuplicator, and the pass itself. The pass delegates
nearly everything to the TailDuplicator object, except for looping over
the blocks in a function. This allows the same code to be used for tail
duplication in both places.

This change, in concert with outlining optional branches, allows
triangle shaped code to perform much better, esepecially when the
taken/untaken branches are correlated, as it creates a second spine when
the tests are small enough.

Issue from previous rollback fixed, and a new test was added for that
case as well. Issue was worklist/scheduling/taildup issue in layout.

Issue from 2nd rollback fixed, with 2 additional tests. Issue was
tail merging/loop info/tail-duplication causing issue with loops that share
a header block.

Differential revision: https://reviews.llvm.org/D18226

llvm-svn: 283619
2016-10-07 22:33:20 +00:00
Kyle Butt 25ac35d822 Revert "Codegen: Tail-duplicate during placement."
This reverts commit 062ace9764953e9769142c1099281a345f9b6bdc.

Issue with loop info and block removal revealed by polly.
I have a fix for this issue already in another patch, I'll re-roll this
together with that fix, and a test case.

llvm-svn: 283292
2016-10-05 01:39:29 +00:00
Kyle Butt adabac2d57 Codegen: Tail-duplicate during placement.
The tail duplication pass uses an assumed layout when making duplication
decisions. This is fine, but passes up duplication opportunities that
may arise when blocks are outlined. Because we want the updated CFG to
affect subsequent placement decisions, this change must occur during
placement.

In order to achieve this goal, TailDuplicationPass is split into a
utility class, TailDuplicator, and the pass itself. The pass delegates
nearly everything to the TailDuplicator object, except for looping over
the blocks in a function. This allows the same code to be used for tail
duplication in both places.

This change, in concert with outlining optional branches, allows
triangle shaped code to perform much better, esepecially when the
taken/untaken branches are correlated, as it creates a second spine when
the tests are small enough.

Issue from previous rollback fixed, and a new test was added for that
case as well.

Differential revision: https://reviews.llvm.org/D18226

llvm-svn: 283274
2016-10-04 23:54:18 +00:00
Kyle Butt 3ffb8529bc Revert "Codegen: Tail-duplicate during placement."
This reverts commit ff234efbe23528e4f4c80c78057b920a51f434b2.

Causing crashes on aarch64 build.

llvm-svn: 283172
2016-10-04 00:38:23 +00:00
Kyle Butt 396bfdd707 Codegen: Tail-duplicate during placement.
The tail duplication pass uses an assumed layout when making duplication
decisions. This is fine, but passes up duplication opportunities that
may arise when blocks are outlined. Because we want the updated CFG to
affect subsequent placement decisions, this change must occur during
placement.

In order to achieve this goal, TailDuplicationPass is split into a
utility class, TailDuplicator, and the pass itself. The pass delegates
nearly everything to the TailDuplicator object, except for looping over
the blocks in a function. This allows the same code to be used for tail
duplication in both places.

This change, in concert with outlining optional branches, allows
triangle shaped code to perform much better, esepecially when the
taken/untaken branches are correlated, as it creates a second spine when
the tests are small enough.

llvm-svn: 283164
2016-10-04 00:00:09 +00:00
David L Kreitzer e7c583e06f Fix for PR27750. Correctly handle the case where the fallthrough block and
target block are the same in getFallThroughMBB.

Differential Revision: http://reviews.llvm.org/D20288

llvm-svn: 269760
2016-05-17 12:47:46 +00:00
Cong Hou 94710840fb Allow X86::COND_NE_OR_P and X86::COND_NP_OR_E to be reversed.
Currently, AnalyzeBranch() fails non-equality comparison between floating points
on X86 (see https://llvm.org/bugs/show_bug.cgi?id=23875). This is because this
function can modify the branch by reversing the conditional jump and removing
unconditional jump if there is a proper fall-through. However, in the case of
non-equality comparison between floating points, this can turn the branch
"unanalyzable". Consider the following case:

jne.BB1
jp.BB1
jmp.BB2
.BB1:
...
.BB2:
...

AnalyzeBranch() will reverse "jp .BB1" to "jnp .BB2" and then "jmp .BB2" will be
removed:

jne.BB1
jnp.BB2
.BB1:
...
.BB2:
...

However, AnalyzeBranch() cannot analyze this branch anymore as there are two
conditional jumps with different targets. This may disable some optimizations
like block-placement: in this case the fall-through behavior is enforced even if
the fall-through block is very cold, which is suboptimal.

Actually this optimization is also done in block-placement pass, which means we
can remove this optimization from AnalyzeBranch(). However, currently
X86::COND_NE_OR_P and X86::COND_NP_OR_E are not reversible: there is no defined
negation conditions for them.

In order to reverse them, this patch defines two new CondCode X86::COND_E_AND_NP
and X86::COND_P_AND_NE. It also defines how to synthesize instructions for them.
Here only the second conditional jump is reversed. This is valid as we only need
them to do this "unconditional jump removal" optimization.


Differential Revision: http://reviews.llvm.org/D11393

llvm-svn: 264199
2016-03-23 21:45:37 +00:00
Sanjay Patel 8c84f74f3a [x86] add test to show missing optimization
This should make it clearer how this proposed patch:
http://reviews.llvm.org/D11393
...will change codegen.

llvm-svn: 262875
2016-03-07 23:13:06 +00:00
Sanjay Patel 55c0dd4b26 [x86] simplify test and tighten checks
I noticed this test as part of:
http://reviews.llvm.org/D11393
...which is confusing enough as-is. 
Let's show the exact codegen, so the changes will be more obvious.

llvm-svn: 262874
2016-03-07 22:53:23 +00:00
Benjamin Kramer d477e9e378 Revert "Allow X86::COND_NE_OR_P and X86::COND_NP_OR_E to be reversed."
and "Add a missing test case for r258847."

This reverts commit r258847, r258848. Causes miscompilations and backend
errors.

llvm-svn: 258927
2016-01-27 12:44:12 +00:00
Cong Hou 551a57f797 Allow X86::COND_NE_OR_P and X86::COND_NP_OR_E to be reversed.
Currently, AnalyzeBranch() fails non-equality comparison between floating points
on X86 (see https://llvm.org/bugs/show_bug.cgi?id=23875). This is because this
function can modify the branch by reversing the conditional jump and removing
unconditional jump if there is a proper fall-through. However, in the case of
non-equality comparison between floating points, this can turn the branch
"unanalyzable". Consider the following case:

jne.BB1
jp.BB1
jmp.BB2
.BB1:
...
.BB2:
...

AnalyzeBranch() will reverse "jp .BB1" to "jnp .BB2" and then "jmp .BB2" will be
removed:

jne.BB1
jnp.BB2
.BB1:
...
.BB2:
...

However, AnalyzeBranch() cannot analyze this branch anymore as there are two
conditional jumps with different targets. This may disable some optimizations
like block-placement: in this case the fall-through behavior is enforced even if
the fall-through block is very cold, which is suboptimal.

Actually this optimization is also done in block-placement pass, which means we
can remove this optimization from AnalyzeBranch(). However, currently
X86::COND_NE_OR_P and X86::COND_NP_OR_E are not reversible: there is no defined
negation conditions for them.

In order to reverse them, this patch defines two new CondCode X86::COND_E_AND_NP
and X86::COND_P_AND_NE. It also defines how to synthesize instructions for them.
Here only the second conditional jump is reversed. This is valid as we only need
them to do this "unconditional jump removal" optimization.


Differential Revision: http://reviews.llvm.org/D11393

llvm-svn: 258847
2016-01-26 20:08:01 +00:00
Bill Wendling 64587097b6 Add testcase to make sure we don't generate too many jumps for a une compare.
<rdar://problem/7859988>

llvm-svn: 191040
2013-09-19 21:58:20 +00:00