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r323355 | nha | 2018-01-24 19:02:05 +0100 (Wed, 24 Jan 2018) | 9 lines
Revert r321751, "StructurizeCFG: Fix broken backedge detection"
It causes regressions in various OpenGL test suites.
Keep the test cases introduced by r321751 as XFAIL, and add a test case
for the regression.
Change-Id: I90b4cc354f68cebe5fcef1f2422dc8fe1c6d3514
Bugzilla: https://bugs.llvm.org/show_bug.cgi?id=36015
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_60@323749 91177308-0d34-0410-b5e6-96231b3b80d8
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r321751 | arsenm | 2018-01-03 10:45:37 -0800 (Wed, 03 Jan 2018) | 25 lines
StructurizeCFG: Fix broken backedge detection
The work order was changed in r228186 from SCC order
to RPO with an arbitrary sorting function. The sorting
function attempted to move inner loop nodes earlier. This
was was apparently relying on an assumption that every block
in a given loop / the same loop depth would be seen before
visiting another loop. In the broken testcase, a block
outside of the loop was encountered before moving onto
another block in the same loop. The testcase would then
structurize such that one blocks unconditional successor
could never be reached.
Revert to plain RPO for the analysis phase. This fixes
detecting edges as backedges that aren't really.
The processing phase does use another visited set, and
I'm unclear on whether the order there is as important.
An arbitrary order doesn't work, and triggers some infinite
loops. The reversed RPO list seems to work and is closer
to the order that was used before, minus the arbitary
custom sorting.
A few of the changed tests now produce smaller code,
and a few are slightly worse looking.
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r321806 | arsenm | 2018-01-04 09:23:24 -0800 (Thu, 04 Jan 2018) | 4 lines
StructurizeCFG: xfail one of the testcases from r321751
It fails with -verify-region-info. This seems to be a issue
with RegionInfo itself which existed before.
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r321878 | arsenm | 2018-01-05 09:51:36 -0800 (Fri, 05 Jan 2018) | 4 lines
RegionInfo: Use report_fatal_error instead of llvm_unreachable
Otherwise when using -verify-region-info in a release build the
error won't be emitted.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_60@322686 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r300732. This breaks a few tests.
I think the problem is related to adding more uses of
the condition that don't yet exist at this point.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301242 91177308-0d34-0410-b5e6-96231b3b80d8
The most common case for a branch condition is
a single use compare. Directly invert the branch
predicate rather than adding a lot of xor i1 true
which the DAG will have to fold later.
This produces nicer to read structurizer output.
This produces some random changes in codegen
due to the DAG swapping branch conditions itself,
and then does a poor job of dealing with those
inverts.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@300732 91177308-0d34-0410-b5e6-96231b3b80d8
If the branch condition for a loop was a phi which itself
was fed from a phi from a loop, it isn't safe to try
to delete the phi until after the loop is handled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@298737 91177308-0d34-0410-b5e6-96231b3b80d8
