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mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-10-19 11:02:59 +02:00
llvm-mirror/unittests
Benjamin Kramer fded9fa4a4 [RemoveDuplicatePHINodes] Start over after removing a PHI.
This makes RemoveDuplicatePHINodes more effective and fixes an assertion
failure. Triggering the assertions requires a DenseSet reallocation
so this change only contains a constructive test.

I'll explain the issue with a small example. In the following function
there's a duplicate PHI, %4 and %5 are identical. When this is found
the DenseSet in RemoveDuplicatePHINodes contains %2, %3 and %4.

define void @F() {
  br label %1

; <label>:1                                       ; preds = %1, %0
  %2 = phi i32 [ 42, %0 ], [ %4, %1 ]
  %3 = phi i32 [ 42, %0 ], [ %5, %1 ]
  %4 = phi i32 [ 42, %0 ], [ 23, %1 ]
  %5 = phi i32 [ 42, %0 ], [ 23, %1 ]
  br label %1
}

after RemoveDuplicatePHINodes runs the function looks like this. %3 has
changed and is now identical to %2, but RemoveDuplicatePHINodes never
saw this.

define void @F() {
  br label %1

; <label>:1                                       ; preds = %1, %0
  %2 = phi i32 [ 42, %0 ], [ %4, %1 ]
  %3 = phi i32 [ 42, %0 ], [ %4, %1 ]
  %4 = phi i32 [ 42, %0 ], [ 23, %1 ]
  br label %1
}

If the DenseSet does a reallocation now it will reinsert all
keys and stumble over %3 now having a different hash value than it had
when inserted into the map for the first time. This change clears the
set whenever a PHI is deleted and starts the progress from the
beginning, allowing %3 to be deleted and avoiding inconsistent DenseSet
state. This potentially has a negative performance impact because
it rescans all PHIs, but I don't think that this ever makes a difference
in practice.

llvm-svn: 246694
2015-09-02 19:52:23 +00:00
..
ADT Teach the target parsing framework to directly compute the length of all 2015-08-30 07:51:04 +00:00
Analysis [ValueTracking] Minor comment change in test 2015-09-02 17:29:54 +00:00
AsmParser AsmParser: Save and restore the parsing state for types using SlotMapping. 2015-08-21 21:32:39 +00:00
Bitcode Fix memory leak in unit test of Bitcode/BitReaderTest.cpp 2015-08-03 21:23:51 +00:00
CodeGen AsmPrinter: Use an intrusively linked list for DIE::Children 2015-06-25 23:52:10 +00:00
DebugInfo Fix compilation of PDBApiTest. 2015-05-01 20:51:49 +00:00
ExecutionEngine Add a global mapping layer for Orc. Adapted from a patch by Andy Somogyi. 2015-08-27 22:20:05 +00:00
IR DI: Set DILexicalBlock columns >= 65536 to 0/unknown 2015-08-28 22:58:50 +00:00
LineEditor Use 'override/final' instead of 'virtual' for overridden methods 2015-04-11 02:11:45 +00:00
Linker Linker: Move distinct MDNodes instead of cloning 2015-08-03 17:09:38 +00:00
MC [cleanup] Re-sort all the #include lines in LLVM using 2015-01-14 11:23:27 +00:00
Option Modify ParseArgs to return the InputArgList by value - there's no need for dynamic allocation/ownership here 2015-06-22 22:06:37 +00:00
ProfileData InstrProf: Add a test for multiple copies of the same with different hashes 2015-06-22 23:56:53 +00:00
Support There is only one saver of strings. 2015-08-13 01:07:02 +00:00
Transforms [RemoveDuplicatePHINodes] Start over after removing a PHI. 2015-09-02 19:52:23 +00:00
CMakeLists.txt AsmParser: Require a terminating null character when creating memory buffer. 2015-05-20 20:41:27 +00:00
Makefile AsmParser: Require a terminating null character when creating memory buffer. 2015-05-20 20:41:27 +00:00
Makefile.unittest With rpaths being set correctly, SHLIBPATH_VAR is not needed anymore. 2014-02-28 16:16:51 +00:00