12 Commits

Author SHA1 Message Date
Tyker
a79e604462 [AssumeBundles] Fix Bug in Assume Queries
this bug was causing miscompile.
now clang cant properly selfhost with -mllvm --enable-knowledge-retention

Reviewed By: jdoerfert, lebedev.ri

Differential Revision: https://reviews.llvm.org/D83507
2020-08-17 21:36:53 +02:00
Eric Christopher
7bfaa40086 Temporarily Revert "[AssumeBundles] Use operand bundles to encode alignment assumptions"
due to the performance bugs filed in https://bugs.llvm.org/show_bug.cgi?id=46753.

An SROA change soon may obviate some of these problems.

This reverts commit 8d09f20798ac180b1749276bff364682ce0196ab.
2020-07-16 11:54:04 -07:00
Tyker
16f777f421 [NFC] Add debug and stat counters to assume queries and assume builder
Summary:
Add debug counter and stats counter to assume queries and assume builder
here is the collected stats on a build of check-llvm + check-clang.
  "assume-builder.NumAssumeBuilt": 2720879,
  "assume-builder.NumAssumesMerged": 761396,
  "assume-builder.NumAssumesRemoved": 1576212,
  "assume-builder.NumBundlesInAssumes": 6518809,
  "assume-queries.NumAssumeQueries": 85566380,
  "assume-queries.NumUsefullAssumeQueries": 2727360,
the NumUsefullAssumeQueries stat is actually pessimistic because in a few places queries
ask to keep providing information to try to get better information. and this isn't counted
as a usefull query evem tho it can be usefull

Reviewers: jdoerfert

Reviewed By: jdoerfert

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D83506
2020-07-14 21:49:14 +02:00
Tyker
8d09f20798 [AssumeBundles] Use operand bundles to encode alignment assumptions
Summary:
NOTE: There is a mailing list discussion on this: http://lists.llvm.org/pipermail/llvm-dev/2019-December/137632.html

Complemantary to the assumption outliner prototype in D71692, this patch
shows how we could simplify the code emitted for an alignemnt
assumption. The generated code is smaller, less fragile, and it makes it
easier to recognize the additional use as a "assumption use".

As mentioned in D71692 and on the mailing list, we could adopt this
scheme, and similar schemes for other patterns, without adopting the
assumption outlining.

Reviewers: hfinkel, xbolva00, lebedev.ri, nikic, rjmccall, spatel, jdoerfert, sstefan1

Reviewed By: jdoerfert

Subscribers: thopre, yamauchi, kuter, fhahn, merge_guards_bot, hiraditya, bollu, rkruppe, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D71739
2020-07-14 01:05:58 +02:00
Roman Lebedev
7ea46aee36
Revert "[AssumeBundles] Use operand bundles to encode alignment assumptions"
Assume bundle can have more than one entry with the same name,
but at least AlignmentFromAssumptionsPass::extractAlignmentInfo() uses
getOperandBundle("align"), which internally assumes that it isn't the
case, and happily crashes otherwise.

Minimal reduced reproducer: run `opt -alignment-from-assumptions` on

target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

%0 = type { i64, %1*, i8*, i64, %2, i32, %3*, i8* }
%1 = type opaque
%2 = type { i8, i8, i16 }
%3 = type { i32, i32, i32, i32 }

; Function Attrs: nounwind
define i32 @f(%0* noalias nocapture readonly %arg, %0* noalias %arg1) local_unnamed_addr #0 {
bb:
  call void @llvm.assume(i1 true) [ "align"(%0* %arg, i64 8), "align"(%0* %arg1, i64 8) ]
  ret i32 0
}

; Function Attrs: nounwind willreturn
declare void @llvm.assume(i1) #1

attributes #0 = { nounwind "reciprocal-estimates"="none" }
attributes #1 = { nounwind willreturn }


This is what we'd have with -mllvm -enable-knowledge-retention

This reverts commit c95ffadb2474a4d8c4f598d94d35a9f31d9606cb.
2020-07-04 23:49:23 +03:00
Tyker
c95ffadb24 [AssumeBundles] Use operand bundles to encode alignment assumptions
Summary:
NOTE: There is a mailing list discussion on this: http://lists.llvm.org/pipermail/llvm-dev/2019-December/137632.html

Complemantary to the assumption outliner prototype in D71692, this patch
shows how we could simplify the code emitted for an alignemnt
assumption. The generated code is smaller, less fragile, and it makes it
easier to recognize the additional use as a "assumption use".

As mentioned in D71692 and on the mailing list, we could adopt this
scheme, and similar schemes for other patterns, without adopting the
assumption outlining.

Reviewers: hfinkel, xbolva00, lebedev.ri, nikic, rjmccall, spatel, jdoerfert, sstefan1

Reviewed By: jdoerfert

Subscribers: yamauchi, kuter, fhahn, merge_guards_bot, hiraditya, bollu, rkruppe, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D71739
2020-06-25 12:59:44 +02:00
Tyker
78d85c2091 [AssumeBundles] fix crashes
Summary:
this patch fixe crash/asserts found in the test-suite.
the AssumeptionCache cannot be assumed to have all assumes contrary to what i tought.
prevent generation of information for terminators, because this can create broken IR in transfromation where we insert the new terminator before removing the old one.

Reviewers: jdoerfert

Reviewed By: jdoerfert

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D79458
2020-05-11 11:52:21 +02:00
OCHyams
da100de0a6 [NFC][DwarfDebug] Add test for variables with a single location which
don't span their entire scope.

The previous commit (6d1c40c171e) is an older version of the test.

Reviewed By: aprantl, vsk

Differential Revision: https://reviews.llvm.org/D79573
2020-05-11 11:49:11 +02:00
Tyker
821a0f23d8 [AssumeBundles] Prevent generation of some redundant assumes
Summary: with this patch the assume salvageKnowledge will not generate assume if all knowledge is already available in an assume with valid context. assume bulider can also in some cases update an existing assume with better information.

Reviewers: jdoerfert

Reviewed By: jdoerfert

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78014
2020-05-10 19:23:59 +02:00
Tyker
e5f8a77c19 [AssumeBundles] Refactor asssume builder
Summary:
refactor assume bulider for the next patch.
the assume builder now generate only one assume per attribute kind and per value they are on. to do this it takes the highest. this is desirable because currently, for all attributes the higest value is the most valuable.

Reviewers: jdoerfert

Reviewed By: jdoerfert

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78013
2020-04-25 13:43:52 +02:00
Tyker
42431da895 [AssumeBundles] Use assume bundles in isKnownNonZero
Summary: Use nonnull and dereferenceable from an assume bundle in isKnownNonZero

Reviewers: jdoerfert, nikic, lebedev.ri, reames, fhahn, sstefan1

Reviewed By: jdoerfert

Subscribers: fhahn, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D76149
2020-04-24 20:41:51 +02:00
Tyker
c00cb76274 [NFC] Split Knowledge retention and place it more appropriatly
Summary:
Splitting Knowledge retention into Queries in Analysis and Builder into Transform/Utils
allows Queries and Transform/Utils to use Analysis.

Reviewers: jdoerfert, sstefan1

Reviewed By: jdoerfert

Subscribers: mgorny, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77171
2020-04-02 15:01:41 +02:00