CoalescerPair can determine if a copy can be coalesced, and which register gets
merged away. The old logic in SimpleRegisterCoalescing had evolved into
something a bit too convoluted.

This second attempt fixes some crashes that only occurred Linux.

llvm-svn: 106769

llvm-svn: 106768

[L]oad, [u]se, [d]ef, or [S]tore slots.

This makes it easier to see if two indices refer to the same instruction,
avoiding mental mod 4 calculations.

llvm-svn: 106766

which trivially fold away.

llvm-svn: 106765

llvm-svn: 106764

enough special case, and it theoretically allows more folding because
it works even when x is unanalyzable.

llvm-svn: 106763

form so they can be narrowed to 16-bit instructions.

llvm-svn: 106762

None of the existing implementations of commuteInstruction create new
instructions unless the NewMI parameter is true, but the comment had
implied otherwise.

findCommutedOpIndices returns false, not true, when it doesn't know
how to commute the instruction.

llvm-svn: 106761

was over-complicated.

llvm-svn: 106760

llvm-svn: 106759

Thanks Daniel D.

llvm-svn: 106758

handling of pointer types.

llvm-svn: 106757

llvm-svn: 106756

llvm-svn: 106755

instead of a StringRef, avoiding the need to copy the string in the
common case.

llvm-svn: 106754

Also keep track of the original DstREg before subregister adjustments.

llvm-svn: 106753

llvm-svn: 106752

In this case it is essential that the kill is real because the spiller will
decide to omit a spill if it thinks there is a later kill.

llvm-svn: 106751

llvm-svn: 106750

as many tests as possible.

llvm-svn: 106749

when the condition is constant. This optimization shouldn't be
necessary, because codegen shouldn't be able to find dead control
paths that the IR-level optimizer can't find. And it's undesirable,
because it encourages bugpoint to leave "br i1 false" branches
in its output. And it wasn't updating the CFG.

I updated all the tests I could, but some tests are too reduced
and I wasn't able to meaningfully preserve them.

llvm-svn: 106748

llvm-svn: 106747

llvm-svn: 106746

llvm-svn: 106745

llvm-svn: 106744

llvm-svn: 106743

llvm-svn: 106742

llvm-svn: 106741

llvm-svn: 106740

llvm-svn: 106738

llvm-svn: 106737

llvm-svn: 106736

llvm-svn: 106734

The constant was copied from clang's limits.h.

llvm-svn: 106732

llvm-svn: 106731

llvm-svn: 106730

llvm-svn: 106729

llvm-svn: 106728

llvm-svn: 106727

llvm-svn: 106726