[llvm-commits] [llvm] r57428 - /llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp
Chris Lattner
sabre at nondot.org
Sun Oct 12 18:59:14 PDT 2008
Author: lattner
Date: Sun Oct 12 20:59:13 2008
New Revision: 57428
URL: http://llvm.org/viewvc/llvm-project?rev=57428&view=rev
Log:
calls can be supported.
Modified:
llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp?rev=57428&r1=57427&r2=57428&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp Sun Oct 12 20:59:13 2008
@@ -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.
//
//===----------------------------------------------------------------------===//
More information about the llvm-commits
mailing list