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author | Chris Lattner <sabre@nondot.org> | 2008-10-13 01:59:13 +0000 |
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committer | Chris Lattner <sabre@nondot.org> | 2008-10-13 01:59:13 +0000 |
commit | 44d2a983b76a2a923e34f3162c960443425cb296 (patch) | |
tree | 6fe66185126cacd03066cf5c44b605d53be9efa6 /lib/CodeGen | |
parent | cdb0e4caff8fea9e9065f6483c4c6dc44a61f331 (diff) | |
download | external_llvm-44d2a983b76a2a923e34f3162c960443425cb296.zip external_llvm-44d2a983b76a2a923e34f3162c960443425cb296.tar.gz external_llvm-44d2a983b76a2a923e34f3162c960443425cb296.tar.bz2 |
calls can be supported.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57428 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen')
-rw-r--r-- | lib/CodeGen/SelectionDAG/FastISel.cpp | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/lib/CodeGen/SelectionDAG/FastISel.cpp b/lib/CodeGen/SelectionDAG/FastISel.cpp index 77e9bda..b12665b 100644 --- a/lib/CodeGen/SelectionDAG/FastISel.cpp +++ b/lib/CodeGen/SelectionDAG/FastISel.cpp @@ -11,30 +11,30 @@ // // "Fast" instruction selection is designed to emit very poor code quickly. // Also, it is not designed to be able to do much lowering, so most illegal -// types (e.g. i64 on 32-bit targets) and operations (e.g. calls) are not -// supported. It is also not intended to be able to do much optimization, -// except in a few cases where doing optimizations reduces overall compile -// time (e.g. folding constants into immediate fields, because it's cheap -// and it reduces the number of instructions later phases have to examine). +// types (e.g. i64 on 32-bit targets) and operations are not supported. It is +// also not intended to be able to do much optimization, except in a few cases +// where doing optimizations reduces overall compile time. For example, folding +// constants into immediate fields is often done, because it's cheap and it +// reduces the number of instructions later phases have to examine. // // "Fast" instruction selection is able to fail gracefully and transfer // control to the SelectionDAG selector for operations that it doesn't -// support. In many cases, this allows us to avoid duplicating a lot of +// support. In many cases, this allows us to avoid duplicating a lot of // the complicated lowering logic that SelectionDAG currently has. // // The intended use for "fast" instruction selection is "-O0" mode // compilation, where the quality of the generated code is irrelevant when -// weighed against the speed at which the code can be generated. Also, +// weighed against the speed at which the code can be generated. Also, // at -O0, the LLVM optimizers are not running, and this makes the // compile time of codegen a much higher portion of the overall compile -// time. Despite its limitations, "fast" instruction selection is able to +// time. Despite its limitations, "fast" instruction selection is able to // handle enough code on its own to provide noticeable overall speedups // in -O0 compiles. // // Basic operations are supported in a target-independent way, by reading // the same instruction descriptions that the SelectionDAG selector reads, // and identifying simple arithmetic operations that can be directly selected -// from simple operators. More complicated operations currently require +// from simple operators. More complicated operations currently require // target-specific code. // //===----------------------------------------------------------------------===// |