Commit Graph

14 Commits

Author SHA1 Message Date
Nirav Dave d839749ae8 [DAG] Improve Aliasing of operations to static alloca
Re-recommiting after landing DAG extension-crash fix.

Recommiting after adding check to avoid miscomputing alias information
on addresses of the same base but different subindices.

Memory accesses offset from frame indices may alias, e.g., we
may merge write from function arguments passed on the stack when they
are contiguous. As a result, when checking aliasing, we consider the
underlying frame index's offset from the stack pointer.

Static allocs are realized as stack objects in SelectionDAG, but its
offset is not set until post-DAG causing DAGCombiner's alias check to
consider access to static allocas to frequently alias. Modify isAlias
to consider access between static allocas and access from other frame
objects to be considered aliasing.

Many test changes are included here. Most are fixes for tests which
indirectly relied on our aliasing ability and needed to be modified to
preserve their original intent.

The remaining tests have minor improvements due to relaxed
ordering. The exception is CodeGen/X86/2011-10-19-widen_vselect.ll
which has a minor degradation dispite though the pre-legalized DAG is
improved.

Reviewers: rnk, mkuper, jonpa, hfinkel, uweigand

Reviewed By: rnk

Subscribers: sdardis, nemanjai, javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D33345

llvm-svn: 308350
2017-07-18 20:06:24 +00:00
Chandler Carruth a15e080b05 Revert r308025 due to uncovering a crash in SelectionDAG. This is filed
with a minimal test case in http://llvm.org/PR33833.

Original commit message:
  Improve Aliasing of operations to static alloca

llvm-svn: 308271
2017-07-18 07:53:47 +00:00
Nirav Dave a8f63af9d1 Improve Aliasing of operations to static alloca
Recommiting after adding check to avoid miscomputing alias information
on addresses of the same base but different subindices.

Memory accesses offset from frame indices may alias, e.g., we
may merge write from function arguments passed on the stack when they
are contiguous. As a result, when checking aliasing, we consider the
underlying frame index's offset from the stack pointer.

Static allocs are realized as stack objects in SelectionDAG, but its
offset is not set until post-DAG causing DAGCombiner's alias check to
consider access to static allocas to frequently alias. Modify isAlias
to consider access between static allocas and access from other frame
objects to be considered aliasing.

Many test changes are included here. Most are fixes for tests which
indirectly relied on our aliasing ability and needed to be modified to
preserve their original intent.

The remaining tests have minor improvements due to relaxed
ordering. The exception is CodeGen/X86/2011-10-19-widen_vselect.ll
which has a minor degradation dispite though the pre-legalized DAG is
improved.

Reviewers: rnk, mkuper, jonpa, hfinkel, uweigand

Reviewed By: rnk

Subscribers: sdardis, nemanjai, javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D33345

llvm-svn: 308025
2017-07-14 13:56:21 +00:00
Matthias Braun b38736706e Revert "[DAG] Improve Aliasing of operations to static alloca"
Reverting as it breaks tramp3d-v4 in the llvm test-suite. I added some
comments to https://reviews.llvm.org/D33345 about it.

This reverts commit r307546.

llvm-svn: 307589
2017-07-10 20:51:30 +00:00
Nirav Dave 163e1ad9dc [DAG] Improve Aliasing of operations to static alloca
Memory accesses offset from frame indices may alias, e.g., we
may merge write from function arguments passed on the stack when they
are contiguous. As a result, when checking aliasing, we consider the
underlying frame index's offset from the stack pointer.

Static allocs are realized as stack objects in SelectionDAG, but its
offset is not set until post-DAG causing DAGCombiner's alias check to
consider access to static allocas to frequently alias. Modify isAlias
to consider access between static allocas and access from other frame
objects to be considered aliasing.

Many test changes are included here. Most are fixes for tests which
indirectly relied on our aliasing ability and needed to be modified to
preserve their original intent.

The remaining tests have minor improvements due to relaxed
ordering. The exception is CodeGen/X86/2011-10-19-widen_vselect.ll
which has a minor degradation dispite though the pre-legalized DAG is
improved.

Reviewers: rnk, mkuper, jonpa, hfinkel, uweigand

Reviewed By: rnk

Subscribers: sdardis, nemanjai, javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D33345

llvm-svn: 307546
2017-07-10 15:39:41 +00:00
Quentin Colombet fb82c7bc94 [X86] Fix tailcall return address clobber bug.
This bug (llvm.org/PR28124) was introduced by r237977, which refactored
the tail call  sequence to be generated in two passes instead of one.

Unfortunately, the stack adjustment produced by the first pass was not
recognized by X86FrameLowering::mergeSPUpdates() in all cases, causing
code such as the following, which clobbers the return address, to be
generated:

popl    %edi
popl    %edi
pushl   %eax
jmp     tailcallee              # TAILCALL

To fix the problem, the entire stack adjustment is performed in
X86ExpandPseudo::ExpandMI() for tail calls.

Patch by Magnus Lång <margnus1@gmail.com>

Differential Revision: http://reviews.llvm.org/D21325

llvm-svn: 275103
2016-07-11 21:03:03 +00:00
Michael Kuperstein 0194d30e09 [X86] Extract HiPE prologue constants into metadata
X86FrameLowering::adjustForHiPEPrologue() contains a hard-coded offset
into an Erlang Runtime System-internal data structure (the PCB). As the
layout of this data structure is prone to change, this poses problems
for maintaining compatibility.

To address this problem, the compiler can produce this information as
module-level named metadata. For example (where P_NSP_LIMIT is the
offending offset):

!hipe.literals = !{ !2, !3, !4 }
!2 = !{ !"P_NSP_LIMIT", i32 152 }
!3 = !{ !"X86_LEAF_WORDS", i32 24 }
!4 = !{ !"AMD64_LEAF_WORDS", i32 24 }

Patch by Magnus Lang

Differential Revision: http://reviews.llvm.org/D20363

llvm-svn: 273593
2016-06-23 18:17:25 +00:00
Zia Ansari 30a02384f7 Implemented stack symbol table ordering/packing optimization to improve data locality and code size from SP/FP offset encoding.
Differential Revision: http://reviews.llvm.org/D15393

llvm-svn: 260917
2016-02-15 23:44:13 +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
Andrew Trick e97d8d6dde Enable MI Sched for x86.
This changes the SelectionDAG scheduling preference to source
order. Soon, the SelectionDAG scheduler can be bypassed saving
a nice chunk of compile time.

Performance differences that result from this change are often a
consequence of register coalescing. The register coalescer is far from
perfect. Bugs can be filed for deficiencies.

On x86 SandyBridge/Haswell, the source order schedule is often
preserved, particularly for small blocks.

Register pressure is generally improved over the SD scheduler's ILP
mode. However, we are still able to handle large blocks that require
latency hiding, unlike the SD scheduler's BURR mode. MI scheduler also
attempts to discover the critical path in single-block loops and
adjust heuristics accordingly.

The MI scheduler relies on the new machine model. This is currently
unimplemented for AVX, so we may not be generating the best code yet.

Unit tests are updated so they don't depend on SD scheduling heuristics.

llvm-svn: 192750
2013-10-15 23:33:07 +00:00
Andrew Trick 121124acf8 Revert "Temporarily enable MI-Sched on X86."
This reverts commit 98a9b72e8c56dc13a2617de84503a3d78352789c.

llvm-svn: 184823
2013-06-25 02:48:58 +00:00
Andrew Trick 5a1e0af838 Temporarily enable MI-Sched on X86.
Sorry for the unit test churn. I'll try to make the change permanently
next time.

llvm-svn: 184705
2013-06-24 09:13:20 +00:00
NAKAMURA Takumi 0ff86ac8a6 llvm/test/CodeGen/X86/hipe-cc*.ll: Add explicit -mcpu, or they don't expect to pass on Atom.
llvm-svn: 168171
2012-11-16 16:07:37 +00:00
Duncan Sands d71b4e4568 Add the Erlang/HiPE calling convention, patch by Yiannis Tsiouris.
llvm-svn: 168166
2012-11-16 12:36:39 +00:00