elements that have been erased.  Based on a patch
by Nicolas Capens.

llvm-svn: 51485

llvm-svn: 51484

This fixes recent CBE regressions.

llvm-svn: 51483

llvm-svn: 51482

I've tried to make the distinction between the DejaGNU tests and the test-suite
more clear, added a small section about generating output from the test-suite,
removed some duplication and fixed some wordings. Most of the changes are text
movements, however.

llvm-svn: 51480

llvm-svn: 51479

The SimplifyCFG pass looks at basic blocks that contain only phi nodes,
followed by an unconditional branch. In a lot of cases, such a block (BB) can
be merged into their successor (Succ).

This merging is performed by TryToSimplifyUncondBranchFromEmptyBlock. It does
this by taking all phi nodes in the succesor block Succ and expanding them to
include the predecessors of BB. Furthermore, any phi nodes in BB are moved to
Succ and expanded to include the predecessors of Succ as well.

Before attempting this merge, CanPropagatePredecessorsForPHIs checks to see if
all phi nodes can be properly merged. All functional changes are made to
this function, only comments were updated in
TryToSimplifyUncondBranchFromEmptyBlock.

In the original code, CanPropagatePredecessorsForPHIs looks quite convoluted
and more like stack of checks added to handle different kinds of situations
than a comprehensive check. In particular the first check in the function did
some value checking for the case that BB and Succ have a common predecessor,
while the last check in the function simply rejected all cases where BB and
Succ have a common predecessor. The first check was still useful in the case
that BB did not contain any phi nodes at all, though, so it was not completely
useless.

Now, CanPropagatePredecessorsForPHIs is restructured to to look a lot more
similar to the code that actually performs the merge. Both functions now look
at the same phi nodes in about the same order.  Any conflicts (phi nodes with
different values for the same source) that could arise from merging or moving
phi nodes are detected. If no conflicts are found, the merge can happen.

Apart from only restructuring the checks, two main changes in functionality
happened.

Firstly, the old code rejected blocks with common predecessors in most cases.
The new code performs some extra checks so common predecessors can be handled
in a lot of cases. Wherever common predecessors still pose problems, the
blocks are left untouched.

Secondly, the old code rejected the merge when values (phi nodes) from BB were
used in any other place than Succ. However, it does not seem that there is any
situation that would require this check. Even more, this can be proven.

Consider that BB is a block containing of a single phi node "%a" and a branch
to Succ. Now, since the definition of %a will dominate all of its uses, BB
will dominate all blocks that use %a. Furthermore, since the branch from BB to
Succ is unconditional, Succ will also dominate all uses of %a.

Now, assume that one predecessor of Succ is not dominated by BB (and thus not
dominated by Succ). Since at least one use of %a (but in reality all of them)
is reachable from Succ, you could end up at a use of %a without passing
through it's definition in BB (by coming from X through Succ). This is a
contradiction, meaning that our original assumption is wrong. Thus, all
predecessors of Succ must also be dominated by BB (and thus also by Succ).

This means that moving the phi node %a from BB to Succ does not pose any
problems when the two blocks are merged, and any use checks are not needed.

llvm-svn: 51478

llvm-svn: 51477

llvm-svn: 51476

llvm-svn: 51475

llvm-svn: 51474

instruction for doing this?

llvm-svn: 51473

llvm-svn: 51472

llvm-svn: 51471

llvm-svn: 51470

and/or to handle more cases (such as this add-sitofp.ll testcase), and
port it to selectiondag's ComputeNumSignBits.

llvm-svn: 51469

and bitcode support for the extractvalue and insertvalue
instructions and constant expressions.

Note that this does not yet include CodeGen support.

llvm-svn: 51468

exclude struct and array types.

llvm-svn: 51467

llvm-svn: 51466

llvm-svn: 51465

in gcc.dg/pr27531-1.c.

llvm-svn: 51464

llvm-svn: 51463

Bug: rcpps can only folds a load if the address is 16-byte aligned. Fixed many 'ps' load folding patterns in X86InstrSSE.td which are missing the proper alignment checks.
Also fixed some 80 col. violations.

llvm-svn: 51462

instructions.

llvm-svn: 51461

exclude struct and array types.

llvm-svn: 51460

exclude struct and array types.

llvm-svn: 51459

g++.dg/abi/key2.C

llvm-svn: 51458

Reading .bc files from before that change will no longer work.

llvm-svn: 51457

exclude struct and array types.

llvm-svn: 51456

X86CodeEmitter should not set PIC style to None at initialization time. This will break codegen if relocation model is changed to PIC_ later.

llvm-svn: 51455

llvm-svn: 51454

llvm-svn: 51453

exclude struct and array types.

llvm-svn: 51452

Also added a FIXME related to how we represent @properties in the ObjCInterfaceDecl AST.

llvm-svn: 51450

llvm-svn: 51449

and supported in the grammar, in the lexer.

llvm-svn: 51448

llvm::Type::isSingleValueType. Currently these two functions have
the same behavior, but soon isFirstClassType will return true for
struct and array types.

Clang may some day want to use of isFirstClassType for some of
these some day as an optimization, but it'll require some
consideration.

llvm-svn: 51446

llvm-svn: 51441

When rewriting defs and uses after spilling, don't set the weight of a
live interval to infinity if the instruction being rewritten is an
original remat def instruction.  We were only checking against the clone
of the remat def which doesn't actually appear in the IR at all.

llvm-svn: 51440

Don't attempt to update SpillSlotToUsesMap for stack slots that aren't
generated by the spiller.

llvm-svn: 51439