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| author | Stepan Dyatkovskiy <stpworld@narod.ru> | 2012-08-20 07:57:06 +0000 |
|---|---|---|
| committer | Stepan Dyatkovskiy <stpworld@narod.ru> | 2012-08-20 07:57:06 +0000 |
| commit | 6a638ec521e9fad6ff06b098653d7be2b87ad9e3 (patch) | |
| tree | 1777cdbb4a4ace68970625625bed3ee93851d35c /llvm/test/CodeGen/ARM | |
| parent | b58eec4eaf52a918c4f7afac55afaf17c851f82a (diff) | |
| download | bcm5719-llvm-6a638ec521e9fad6ff06b098653d7be2b87ad9e3.tar.gz bcm5719-llvm-6a638ec521e9fad6ff06b098653d7be2b87ad9e3.zip | |
Fixed DAGCombiner bug (found and localized by James Malloy):
The DAGCombiner tries to optimise a BUILD_VECTOR by checking if it
consists purely of get_vector_elts from one or two source vectors. If
so, it either makes a concat_vectors node or a shufflevector node.
However, it doesn't check the element type width of the underlying
vector, so if you have this sequence:
Node0: v4i16 = ...
Node1: i32 = extract_vector_elt Node0
Node2: i32 = extract_vector_elt Node0
Node3: v16i8 = BUILD_VECTOR Node1, Node2, ...
It will attempt to:
Node0: v4i16 = ...
NewNode1: v16i8 = concat_vectors Node0, ...
Where this is actually invalid because the element width is completely
different. This causes an assertion failure on DAG legalization stage.
Fix:
If output item type of BUILD_VECTOR differs from input item type.
Make concat_vectors based on input element type and then bitcast it to the output vector type. So the case described above will transformed to:
Node0: v4i16 = ...
NewNode1: v8i16 = concat_vectors Node0, ...
NewNode2: v16i8 = bitcast NewNode1
llvm-svn: 162195
Diffstat (limited to 'llvm/test/CodeGen/ARM')
0 files changed, 0 insertions, 0 deletions
