to determine where to place PHIs by iteratively comparing reaching definitions
at each block. That was just plain wrong. This version now computes the
dominator tree within the subset of the CFG where PHIs may need to be placed,
and then places the PHIs in the iterated dominance frontier of each definition.
The rest of the patch is mostly the same, with a few more performance
improvements added in.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101612 91177308-0d34-0410-b5e6-96231b3b80d8
(what was I thinking?) and there's also a problem with LCSSA. I'll try again
later with fixes.
--- Reverse-merging r100263 into '.':
U lib/Transforms/Utils/SSAUpdater.cpp
--- Reverse-merging r100177 into '.':
G lib/Transforms/Utils/SSAUpdater.cpp
--- Reverse-merging r100148 into '.':
G lib/Transforms/Utils/SSAUpdater.cpp
--- Reverse-merging r100147 into '.':
U include/llvm/Transforms/Utils/SSAUpdater.h
G lib/Transforms/Utils/SSAUpdater.cpp
--- Reverse-merging r100131 into '.':
G include/llvm/Transforms/Utils/SSAUpdater.h
G lib/Transforms/Utils/SSAUpdater.cpp
--- Reverse-merging r100130 into '.':
G lib/Transforms/Utils/SSAUpdater.cpp
--- Reverse-merging r100126 into '.':
G include/llvm/Transforms/Utils/SSAUpdater.h
G lib/Transforms/Utils/SSAUpdater.cpp
--- Reverse-merging r100050 into '.':
D test/Transforms/GVN/2010-03-31-RedundantPHIs.ll
--- Reverse-merging r100047 into '.':
G include/llvm/Transforms/Utils/SSAUpdater.h
G lib/Transforms/Utils/SSAUpdater.cpp
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100264 91177308-0d34-0410-b5e6-96231b3b80d8
PHIs. The previous algorithm was unable to reliably detect when existing
PHIs in a cycle can be reused. I'm still working on reducing a testcase.
Radar 7711900.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100047 91177308-0d34-0410-b5e6-96231b3b80d8
This was already being done in SSAUpdater::GetValueAtEndOfBlock so I've
just changed SSAUpdater to check for existing PHIs in both places.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94690 91177308-0d34-0410-b5e6-96231b3b80d8
'GetValueInMiddleOfBlock' case, instead of inserting
duplicates.
A similar fix is almost certainly needed by the machine-level
SSAUpdate implementation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91820 91177308-0d34-0410-b5e6-96231b3b80d8
When an incoming value for a PHI is updated, we must also updated all other
incoming values for the same BB to match, otherwise we create invalid PHIs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84638 91177308-0d34-0410-b5e6-96231b3b80d8
not just at the end. Add a big comment explaining when this could
be useful (which never happens for jump threading).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83741 91177308-0d34-0410-b5e6-96231b3b80d8
