add a fixme

llvm-svn: 86766

implement a TODO by teaching jump threading about "xor x, 1".

llvm-svn: 86739

move some generally useful functions out of jump threading
into libanalysis and transformutils.

llvm-svn: 86735

improve comment.

llvm-svn: 86723

Make jump threading eliminate blocks that just contain phi nodes,
debug intrinsics, and an unconditional branch when possible. This
reuses the TryToSimplifyUncondBranchFromEmptyBlock function split

Make jump threading eliminate blocks that just contain phi nodes,
debug intrinsics, and an unconditional branch when possible. This
reuses the TryToSimplifyUncondBranchFromEmptyBlock function split
out of simplifycfg.

llvm-svn: 86722

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make jump threading recursively simplify expressions instead of doing it
just one level deep. On the testcase we go from getting this:

F1: ; preds = %

make jump threading recursively simplify expressions instead of doing it
just one level deep. On the testcase we go from getting this:

F1: ; preds = %T2
%F = and i1 true, %cond ; <i1> [#uses=1]
br i1 %F, label %X, label %Y

to a fully threaded:

F1: ; preds = %T2
br label %Y


This changes gets us to the point where we're forming (too many) switch
instructions on doug's strswitch testcase.

llvm-svn: 86646

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don't invalidate PN, rewrite of this code is in progress anyway.

llvm-svn: 86639

add a new SimplifyInstruction API, which is like ConstantFoldInstruction,
except that the result may not be a constant. Switch jump threading to
use it so that it gets things like (X & 0) -> 0, wh

add a new SimplifyInstruction API, which is like ConstantFoldInstruction,
except that the result may not be a constant. Switch jump threading to
use it so that it gets things like (X & 0) -> 0, which occur when phi preds
are deleted and the remaining phi pred was a zero.

llvm-svn: 86637

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rename SimplifyCompare -> SimplifyCmpInst and split it into
Simplify[IF]Cmp pieces. Add some predicates to CmpInst to
determine whether a predicate is fp or int.

llvm-svn: 86624

use instructionsimplify instead of a weak clone of ad-hoc folding stuff.

llvm-svn: 86616

stub out a new form of BasicBlock::RemovePredecessorAndSimplify which
simplifies instruction users of PHIs when the phi is eliminated. This
will be moved to transforms/utils after some other refacto

stub out a new form of BasicBlock::RemovePredecessorAndSimplify which
simplifies instruction users of PHIs when the phi is eliminated. This
will be moved to transforms/utils after some other refactoring.

llvm-svn: 86603

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comment typos pointed out by Duncan

llvm-svn: 86497

reapply 86289, 86278, 86270, 86267, 86266 & 86264 plus a fix
(making pred factoring only happen if threading is guaranteed
to be successful).

This now survives an X86-64 bootstrap of llvm-gcc.

llvm

reapply 86289, 86278, 86270, 86267, 86266 & 86264 plus a fix
(making pred factoring only happen if threading is guaranteed
to be successful).

This now survives an X86-64 bootstrap of llvm-gcc.

llvm-svn: 86355

show more ...

Revert following patches to fix llvmgcc bootstrap.
86289, 86278, 86270, 86267, 86266 & 86264
Chris, please take a look.

llvm-svn: 86321

Avoid "ambiguous 'else'" warning from gcc.

llvm-svn: 86314

Fix a bug where we'd call SplitBlockPredecessors with a pred in the
set only once even if it has multiple edges to BB.

llvm-svn: 86299

Remove function left over from other jump threading cleanup.

llvm-svn: 86289

Fix a problem discovered on self host.

llvm-svn: 86278

remove more code subsumed by r86264

llvm-svn: 86270

eliminate some more code subsumed by r86264

llvm-svn: 86267

remove now redundant code, r86264 handles this case.

llvm-svn: 86266

Extend jump threading to support much more general threading
predicates. This allows us to jump thread things like:

_ZN12StringSwitchI5ColorE4CaseILj7EEERS1_RAT__KcRKS0_.exit119:
%tmp1.i24166 = p

Extend jump threading to support much more general threading
predicates. This allows us to jump thread things like:

_ZN12StringSwitchI5ColorE4CaseILj7EEERS1_RAT__KcRKS0_.exit119:
%tmp1.i24166 = phi i8 [ 1, %bb5.i117 ], [ %tmp1.i24165, %_Z....exit ], [ %tmp1.i24165, %bb4.i114 ]
%toBoolnot.i87 = icmp eq i8 %tmp1.i24166, 0 ; <i1> [#uses=1]
%tmp4.i90 = icmp eq i32 %tmp2.i, 6 ; <i1> [#uses=1]
%or.cond173 = and i1 %toBoolnot.i87, %tmp4.i90 ; <i1> [#uses=1]
br i1 %or.cond173, label %bb4.i96, label %_ZN12...

Where it is "obvious" that when coming from %bb5.i117 that the 'and' is always
false. This triggers a surprisingly high number of times in the testsuite,
and gets us closer to generating good code for doug's strswitch testcase.

This also make a bunch of other code in jump threading redundant, I'll rip
out in the next patch. This survived an enable-checking llvm-gcc bootstrap.

llvm-svn: 86264

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remove a bunch of extraneous LLVMContext arguments
from various APIs, addressing PR5325.

llvm-svn: 86231

improve DSE when TargetData is not around, based on work by
Hans Wennborg!

llvm-svn: 86067

when folding duplicate conditions, delete the
now-probably-dead instruction tree feeding it.

llvm-svn: 83778