branch is not necessary immediate dominators of merge blcok in all cases.

llvm-svn: 41144

llvm-svn: 40604

llvm-svn: 40034

llvm-gcc build to succeed. Without this change it fails in libstdc++
compilation. This causes no regressions in dejagnu tests. However, 
someone who knows this code better might want to review it.

llvm-svn: 39924

llvm-svn: 39844

This adds redundancy for now.

llvm-svn: 37492

llvm-svn: 37407

llvm-svn: 37403

llvm-svn: 36994

llvm-svn: 36873

llvm-svn: 36662

Due to darwin gcc bug, one version of darwin linker coalesces
static const int, which defauts PassID based pass identification.

llvm-svn: 36652

llvm-svn: 36632

llvm-svn: 36258

llvm-svn: 36247

llvm-svn: 36017

the Transforms library. This reduces debug library size by 132 KB, debug
binary size by 376 KB, and reduces link time for llvm tools slightly.

llvm-svn: 33939

Revert last patch which caused iteration invalidation.

llvm-svn: 33901

llvm-svn: 33897

delete some dead ones.

llvm-svn: 32694

is 'unsigned'.

llvm-svn: 32279

Transforms/LCSSA/2006-10-31-UnreachableBlock-2.ll

llvm-svn: 31317

llvm-svn: 31315

llvm-svn: 29925

up lcssa much in practice.

llvm-svn: 29465

down approach, inspired by discussions with Tanya.

This approach is significantly faster, because it does not need dominator
frontiers and it does not insert extraneous unused PHI nodes.  For example, on
252.eon, in a release-asserts build, this speeds up LCSSA (which is the slowest
pass in gccas) from 9.14s to 0.74s on my G5.  This code is also slightly smaller
and significantly simpler than the old code.

Amusingly, in a normal Release build (which includes the
"assert(L->isLCSSAForm());" assertion), asserting that the result of LCSSA
is in LCSSA form is actually slower than the LCSSA transformation pass
itself on 252.eon.  I will see if Loop::isLCSSAForm can be sped up next.

llvm-svn: 29463

llvm-svn: 29078

cases.  Ideally, this issue will go away in the future as LCSSA gets smarter
about which Phi nodes it inserts.

llvm-svn: 29076

LCSSA is still the slowest pass when gccas'ing 252.eon, but now it only takes
39s instead of 289s. :)

llvm-svn: 28776

llvm-svn: 28774

not handling PHI nodes correctly when determining if a value was live-out.

This patch reduces the number of detected live-out variables in the testcase
from 6565 to 485.

llvm-svn: 28771

If a single exit block has multiple predecessors within the loop, it will
appear in the exit blocks list more than once.  LCSSA needs to take that into
account so that it doesn't double process that exit block.

llvm-svn: 28750

llvm-svn: 28748

Back out Owen's 6/9 changes. They broke MultiSource/Benchmarks/Prolangs-C/bison (and perhaps others).

llvm-svn: 28747

on this.

llvm-svn: 28738

require LCSSA.

llvm-svn: 28734

llvm-svn: 28694

llvm-svn: 28693

llvm-svn: 28680

llvm-svn: 28678