[SimplifyCFG] Stop inserting calls to llvm.trap for UB

SimplifyCFG had logic to insert calls to llvm.trap for two very
particular IR patterns: stores and invokes of undef/null.

While InstCombine ca

[SimplifyCFG] Stop inserting calls to llvm.trap for UB

SimplifyCFG had logic to insert calls to llvm.trap for two very
particular IR patterns: stores and invokes of undef/null.

While InstCombine canonicalizes certain undefined behavior IR patterns
to stores of undef, phase ordering means that this cannot be relied upon
in general.

There are much better tools than llvm.trap: UBSan and ASan.

N.B. I could be argued into reverting this change if a clear argument as
to why it is important that we synthesize llvm.trap for stores, I'd be
hard pressed to see why it'd be useful for invokes...

llvm-svn: 273778

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[SimplifyCFG] Replace calls to null/undef with unreachable

Calling null is undefined behavior, a call to undef can be trivially
treated as a call to null.

llvm-svn: 273776

Reinstate r273711

r273711 was reverted by r273743. The inliner needs to know about any
call sites in the inlined function. These were obscured if we replaced
a call to undef with an undef but kept

Reinstate r273711

r273711 was reverted by r273743. The inliner needs to know about any
call sites in the inlined function. These were obscured if we replaced
a call to undef with an undef but kept the call around.

This fixes PR28298.

llvm-svn: 273753

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Revert r273711, it caused PR28298.

llvm-svn: 273743

SimplifyInstruction does not imply DCE

We cannot remove an instruction with no uses just because
SimplifyInstruction succeeds. It may have side effects.

llvm-svn: 273711

[sanitizers] Disable target-specific lowering of string functions.

CodeGen has hooks that allow targets to emit specialized code instead
of calls to memcmp, memchr, strcpy, stpcpy, strcmp, strlen, s

[sanitizers] Disable target-specific lowering of string functions.

CodeGen has hooks that allow targets to emit specialized code instead
of calls to memcmp, memchr, strcpy, stpcpy, strcmp, strlen, strnlen.
When ASan/MSan/TSan/ESan is in use, this sidesteps its interceptors, resulting
in uninstrumented memory accesses. To avoid that, make these sanitizers
mark the calls as nobuiltin.

Differential Revision: http://reviews.llvm.org/D19781

llvm-svn: 273083

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[safestack] Fixup llvm.dbg.value when rewriting unsafe allocas.

When moving unsafe allocas to the unsafe stack, dbg.declare intrinsics are
updated to refer to the new location.

This change does the

[safestack] Fixup llvm.dbg.value when rewriting unsafe allocas.

When moving unsafe allocas to the unsafe stack, dbg.declare intrinsics are
updated to refer to the new location.

This change does the same to dbg.value intrinsics.

llvm-svn: 272968

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Revert r272891 "[JumpThreading] Prevent dangling pointer problems in BranchProbabilityInfo"

It was causing failures in Profile-i386 and Profile-x86_64 tests.

llvm-svn: 272912

[JumpThreading] Prevent dangling pointer problems in BranchProbabilityInfo

We should update results of the BranchProbabilityInfo after removing block in JumpThreading. Otherwise
we will get danglin

[JumpThreading] Prevent dangling pointer problems in BranchProbabilityInfo

We should update results of the BranchProbabilityInfo after removing block in JumpThreading. Otherwise
we will get dangling pointer inside BranchProbabilityInfo cache.

Differential Revision: http://reviews.llvm.org/D20957

llvm-svn: 272891

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[InstCombine] Catch more bswap cases missed due to zext and truncs.

Fixes PR27824.
Differential Revision: http://reviews.llvm.org/D20591.

llvm-svn: 270853

Clarify that we match BSwap in InstCombine and BitReverse in CGP. NFC.

Also, rename recognizeBitReverseOrBSwapIdiom to recognizeBSwapOrBitReverseIdiom,
so the ordering of the MatchBSwaps and MatchBi

Clarify that we match BSwap in InstCombine and BitReverse in CGP. NFC.

Also, rename recognizeBitReverseOrBSwapIdiom to recognizeBSwapOrBitReverseIdiom,
so the ordering of the MatchBSwaps and MatchBitReversals arguments are
consistent with the function name.

llvm-svn: 270715

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Fix 80-column violation.

llvm-svn: 270329

Revert "[SimplifyCFG] Extend TryToSimplifyUncondBranchFromEmptyBlock for empty block including lifetime intrinsics"

This reverts commit r268254.

This change causes assertion failures while building

Revert "[SimplifyCFG] Extend TryToSimplifyUncondBranchFromEmptyBlock for empty block including lifetime intrinsics"

This reverts commit r268254.

This change causes assertion failures while building Chromium. Reduced
test case coming soon.

llvm-svn: 268288

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[SimplifyCFG] Extend TryToSimplifyUncondBranchFromEmptyBlock for empty block including lifetime intrinsics

Make it possible that TryToSimplifyUncondBranchFromEmptyBlock merges empty
basic block incl

[SimplifyCFG] Extend TryToSimplifyUncondBranchFromEmptyBlock for empty block including lifetime intrinsics

Make it possible that TryToSimplifyUncondBranchFromEmptyBlock merges empty
basic block including lifetime intrinsics as well as phi nodes and
unconditional branch into its successor or predecessor(s).

If successor of empty block has single predecessor, all contents including
lifetime intrinsics are sinked into the successor. Otherwise, they are
hoisted into its predecessor(s) and then merged into the predecessor(s).

Patch by Josh Yoon <josh.yoon@samsung.com>!

Differential Revision: http://reviews.llvm.org/D19257

llvm-svn: 268254

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Mark guards on true as "trivially dead"

This moves some logic added to EarlyCSE in rL268120 into
`llvm::isInstructionTriviallyDead`. Adds a test case for DCE to
demonstrate that passes other than E

Mark guards on true as "trivially dead"

This moves some logic added to EarlyCSE in rL268120 into
`llvm::isInstructionTriviallyDead`. Adds a test case for DCE to
demonstrate that passes other than EarlyCSE can now pick up on the new
information.

llvm-svn: 268126

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[SimplifyCFG] Preserve !llvm.mem.parallel_loop_access when merging

When SimplifyCFG merges identical instructions from both sides of a diamond, it
can preserve !llvm.mem.parallel_loop_access (as it

[SimplifyCFG] Preserve !llvm.mem.parallel_loop_access when merging

When SimplifyCFG merges identical instructions from both sides of a diamond, it
can preserve !llvm.mem.parallel_loop_access (as it does with most of the other
metadata). There's no real data or control dependency change in this case.

llvm-svn: 267515

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[SimplifyCFG] Fold `llvm.guard(false)` to unreachable

Summary:
`llvm.guard(false)` always bails out of the current compilation unit, so
we can prune any control flow following it.

Reviewers: hfinke

[SimplifyCFG] Fold `llvm.guard(false)` to unreachable

Summary:
`llvm.guard(false)` always bails out of the current compilation unit, so
we can prune any control flow following it.

Reviewers: hfinkel, pcc, reames

Subscribers: majnemer, reames, mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D19245

llvm-svn: 266955

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[RS4GC] Lower calls to @llvm.experimental.deoptimize

This changes RS4GC to lower calls to ``@llvm.experimental.deoptimize``
to gc.statepoints wrapping ``__llvm_deoptimize``, and changes
``callsGCLea

[RS4GC] Lower calls to @llvm.experimental.deoptimize

This changes RS4GC to lower calls to ``@llvm.experimental.deoptimize``
to gc.statepoints wrapping ``__llvm_deoptimize``, and changes
``callsGCLeafFunction`` to recognize ``@llvm.experimental.deoptimize``
as a non GC leaf function.

I've had to hard code the ``"__llvm_deoptimize"`` name in
RewriteStatepointsForGC; since ``TargetLibraryInfo`` is available only
during codegen. This isn't without precedent in the codebase, so I'm
not overtly concerned.

llvm-svn: 264456

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ADT: Remove == and != comparisons between ilist iterators and pointers

I missed == and != when I removed implicit conversions between iterators
and pointers in r252380 since they were defined outsid

ADT: Remove == and != comparisons between ilist iterators and pointers

I missed == and != when I removed implicit conversions between iterators
and pointers in r252380 since they were defined outside ilist_iterator.

Since they depend on getNodePtrUnchecked(), they indirectly rely on UB.
This commit removes all uses of these operators. (I'll delete the
operators themselves in a separate commit so that it can be easily
reverted if necessary.)

There should be NFC here.

llvm-svn: 261498

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Debug Info: Teach LdStHasDebugValue() (Local.cpp) about DIExpressions.
This function is used to check whether a dbg.value intrinsic has already
been inserted, but without comparing the DIExpression,

Debug Info: Teach LdStHasDebugValue() (Local.cpp) about DIExpressions.
This function is used to check whether a dbg.value intrinsic has already
been inserted, but without comparing the DIExpression, it would erroneously
fire on split aggregates and only the first scalar would survive.

Found via http://reviews.llvm.org/D16867.
<rdar://problem/24456528>

llvm-svn: 261145

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Avoid overly large SmallPtrSet/SmallSet

These sets perform linear searching in small mode so it is never a good
idea to use SmallSize/N bigger than 32.

llvm-svn: 259283

[SCCP] Remove duplicate code

SCCP has code identical to changeToUnreachable's behavior, switch it
over to just call changeToUnreachable.

No functionality change intended.

llvm-svn: 258654

[InstCombine, SCCP] Consolidate code used to remove instructions

InstCombine and SCCP both want to remove dead code in a very particular
way but using identical means to do so. Share the code betwe

[InstCombine, SCCP] Consolidate code used to remove instructions

InstCombine and SCCP both want to remove dead code in a very particular
way but using identical means to do so. Share the code between the two.

No functionality change is intended.

llvm-svn: 258653

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Fix for two constant propagation problems in GVN with the assume intrinsic
instruction.

Patch by Yuanrui Zhang.

Differential Revision: http://reviews.llvm.org/D16100

llvm-svn: 258435

Stop increasing alignment of externally-visible globals on ELF
platforms.

With ELF, the alignment of a global variable in a shared library will
get copied into an executables linked against it, if t

Stop increasing alignment of externally-visible globals on ELF
platforms.

With ELF, the alignment of a global variable in a shared library will
get copied into an executables linked against it, if the executable even
accesss the variable. So, it's not possible to implicitly increase
alignment based on access patterns, or you'll break existing binaries.

This happened to affect libc++'s std::cout symbol, for example. See
thread: http://thread.gmane.org/gmane.comp.compilers.clang.devel/45311

(This is a re-commit of r257719, without the bug reported in
PR26144. I've tweaked the code to not assert-fail in
enforceKnownAlignment when computeKnownBits doesn't recurse far enough
to find the underlying Alloca/GlobalObject value.)

Differential Revision: http://reviews.llvm.org/D16145

llvm-svn: 257902

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