diff options
| author | Bob Wilson <bob.wilson@apple.com> | 2009-04-13 22:05:19 +0000 |
|---|---|---|
| committer | Bob Wilson <bob.wilson@apple.com> | 2009-04-13 22:05:19 +0000 |
| commit | b1303d05a89972195de023fda432cc621375a27c (patch) | |
| tree | 83ded3f76bc8714c5a7be5b15d6abbd0fa45abcd /include/llvm/CodeGen/SelectionDAGNodes.h | |
| parent | 88c7af096b09ad26cbcebfdf40151e04094b7460 (diff) | |
Change SelectionDAG type legalization to allow BUILD_VECTOR operands to be
promoted to legal types without changing the type of the vector. This is
following a suggestion from Duncan
(http://lists.cs.uiuc.edu/pipermail/llvmdev/2009-February/019923.html).
The transformation that used to be done during type legalization is now
postponed to DAG legalization. This allows the BUILD_VECTORs to be optimized
and potentially handled specially by target-specific code.
It turns out that this is also consistent with an optimization done by the
DAG combiner: a BUILD_VECTOR and INSERT_VECTOR_ELT may be combined by
replacing one of the BUILD_VECTOR operands with the newly inserted element;
but INSERT_VECTOR_ELT allows its scalar operand to be larger than the
element type, with any extra high bits being implicitly truncated. The
result is a BUILD_VECTOR where one of the operands has a type larger the
the vector element type.
Any code that operates on BUILD_VECTORs may now need to be aware of the
potential type discrepancy between the vector element type and the
BUILD_VECTOR operands. This patch updates all of the places that I could
find to handle that case.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68996 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'include/llvm/CodeGen/SelectionDAGNodes.h')
| -rw-r--r-- | include/llvm/CodeGen/SelectionDAGNodes.h | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/include/llvm/CodeGen/SelectionDAGNodes.h b/include/llvm/CodeGen/SelectionDAGNodes.h index 515634908a..aeaf42f03d 100644 --- a/include/llvm/CodeGen/SelectionDAGNodes.h +++ b/include/llvm/CodeGen/SelectionDAGNodes.h @@ -290,7 +290,11 @@ namespace ISD { /// BUILD_VECTOR(ELT0, ELT1, ELT2, ELT3,...) - Return a vector /// with the specified, possibly variable, elements. The number of elements - /// is required to be a power of two. + /// is required to be a power of two. The types of the operands must + /// all be the same. They must match the vector element type, except if an + /// integer element type is not legal for the target, the operands may + /// be promoted to a legal type, in which case the operands are implicitly + /// truncated to the vector element types. BUILD_VECTOR, /// INSERT_VECTOR_ELT(VECTOR, VAL, IDX) - Returns VECTOR with the element |