Commit Graph

14 Commits

Author SHA1 Message Date
Robert Lougher e20030f612 [X86] Avoid SFB - Fix inconsistent codegen with/without debug info(2)
The function findPotentialBlockers may consider debug info instructions as
potential blockers and may stop searching for a store-load pair prematurely.

This patch corrects this and tests the cases where the store is separated
from the load by more than InspectionLimit debug instructions.

Patch by Chris Dawson.

Differential Revision: https://reviews.llvm.org/D62408

llvm-svn: 364829
2019-07-01 18:28:21 +00:00
Tom Stellard f335672218 X86: Clean up pass initialization
Summary:
- Remove redundant initializations from pass constructors that were
  already being initialized by LLVMInitializeX86Target().

- Add initialization function for the FPS pass.

Reviewers: craig.topper

Reviewed By: craig.topper

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63218

llvm-svn: 363221
2019-06-13 02:09:32 +00:00
Robert Lougher 170dfeb2ff Resubmit r360436 "[X86] Avoid SFB - Fix inconsistent codegen with/without debug info"
Fixes https://bugs.llvm.org/show_bug.cgi?id=40969

The functions findPotentiallyBlockedCopies and buildCopy are currently not
accounting for the presence of debug instructions. In the former this results
in the optimization not being trigerred, and in the latter results in
inconsistent codegen.

This patch enables the optimization to be performed in a debug build and
ensures the codegen is consistent with non-debug builds.

Patch by Chris Dawson.

Differential Revision: https://reviews.llvm.org/D61680

llvm-svn: 361527
2019-05-23 18:15:12 +00:00
Robert Lougher 91a9d4ef4b Revert [X86] Avoid SFB - Fix inconsistent codegen with/without debug info
Revert r360436 as it is causing clang-x64-windows-msvc buildbot to fail.

llvm-svn: 360606
2019-05-13 17:36:46 +00:00
Robert Lougher 986b6b86bb [X86] Avoid SFB - Fix inconsistent codegen with/without debug info
Fixes https://bugs.llvm.org/show_bug.cgi?id=40969

The functions findPotentiallyBlockedCopies and buildCopy are currently not
accounting for the presence of debug instructions. In the former this results
in the optimization not being trigerred, and in the latter results in
inconsistent codegen.

This patch enables the optimization to be performed in a debug build and
ensures the codegen is consistent with non-debug builds.

Patch by Chris Dawson.

Differential Revision: https://reviews.llvm.org/D61680

llvm-svn: 360436
2019-05-10 15:55:06 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Craig Topper 291470347a [X86] Fix assert fails in pass X86AvoidSFBPass
Fixes https://bugs.llvm.org/show_bug.cgi?id=38743

The function removeRedundantBlockingStores is supposed to remove any blocking stores contained in each other in lockingStoresDispSizeMap.
But it currently looks only at the previous one, which will miss some cases that result in assert.

This patch refine the function to check all previous layouts until find the uncontained one. So all redundant stores will be removed.

Patch by Pengfei Wang

Differential Revision: https://reviews.llvm.org/D55642

llvm-svn: 349660
2018-12-19 18:45:57 +00:00
Nikita Popov e79477895e [X86] Fix AvoidStoreForwardingBlocks pass for negative displacements
Fixes https://bugs.llvm.org/show_bug.cgi?id=39926.

The size of the first copy was computed as
std::abs(std::abs(LdDisp2) - std::abs(LdDisp1)), which results in
skipped bytes if the signs of LdDisp2 and LdDisp1 differ. As far as
I can see, this should just be LdDisp2 - LdDisp1. The case where
LdDisp1 > LdDisp2 is already handled in the code above, in which case
LdDisp2 is set to LdDisp1 and this subtraction will evaluate to
Size1 = 0, which is the correct value to skip an overlapping copy.

Differential Revision: https://reviews.llvm.org/D55485

llvm-svn: 348750
2018-12-10 10:16:50 +00:00
Matthias Braun a9f900561e X86: Consistently declare pass initializers in X86.h; NFC
This avoids declaring them twice: in X86TargetMachine.cpp and the file
implementing the pass.

llvm-svn: 345801
2018-11-01 00:38:01 +00:00
Lama Saba 9417f7ff2e [X86] - Avoid SFB pass - fix bug in updating the offsets for newly created copies
Change-Id: I169ab6fe7e187727c0298c2a1e2868a683f3e688
llvm-svn: 332849
2018-05-21 16:23:16 +00:00
Nicola Zaghen d34e60ca85 Rename DEBUG macro to LLVM_DEBUG.
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.

In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.

Differential Revision: https://reviews.llvm.org/D43624

llvm-svn: 332240
2018-05-14 12:53:11 +00:00
Adrian Prantl 5f8f34e459 Remove \brief commands from doxygen comments.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.

Patch produced by

  for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done

Differential Revision: https://reviews.llvm.org/D46290

llvm-svn: 331272
2018-05-01 15:54:18 +00:00
Lama Saba a331f91853 [X86] Fix Update Kill Register in Avoid SFB Pass - Bug 37153
Differential Revision: https://reviews.llvm.org/D45823

Change-Id: Icf6f34f6babc3cb2ff5292fde003472473037a71
llvm-svn: 330939
2018-04-26 13:16:11 +00:00
Lama Saba 927468309f [X86] Reduce Store Forward Block issues in HW - Recommit after fixing Bug 36346
If a load follows a store and reloads data that the store has written to memory, Intel microarchitectures can in many cases forward the data directly from the store to the load, This "store forwarding" saves cycles by enabling the load to directly obtain the data instead of accessing the data from cache or memory.
A "store forward block" occurs in cases that a store cannot be forwarded to the load. The most typical case of store forward block on Intel Core microarchiticutre that a small store cannot be forwarded to a large load.
The estimated penalty for a store forward block is ~13 cycles.

This pass tries to recognize and handle cases where "store forward block" is created by the compiler when lowering memcpy calls to a sequence
of a load and a store.

The pass currently only handles cases where memcpy is lowered to XMM/YMM registers, it tries to break the memcpy into smaller copies.
breaking the memcpy should be possible since there is no atomicity guarantee for loads and stores to XMM/YMM.

Differential revision: https://reviews.llvm.org/D41330

Change-Id: Ib48836ccdf6005989f7d4466fa2035b7b04415d9
llvm-svn: 328973
2018-04-02 13:48:28 +00:00