X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=utils%2FTableGen%2FFastISelEmitter.cpp;h=3ce764259898e39887f7286b812eba9696ec9254;hb=20072af3b0b22d90afbce769409f4ed822520366;hp=0aa9dfc49d4a3204efc6eb9cb083188840b21b57;hpb=98d2d07d416b3431a298eec5a2bfe8b39652c3aa;p=oota-llvm.git

diff --git a/utils/TableGen/FastISelEmitter.cpp b/utils/TableGen/FastISelEmitter.cpp
index 0aa9dfc49d4..3ce76425989 100644
--- a/utils/TableGen/FastISelEmitter.cpp
+++ b/utils/TableGen/FastISelEmitter.cpp
@@ -7,32 +7,14 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This tablegen backend emits a "fast" instruction selector.
+// This tablegen backend emits code for use by the "fast" instruction
+// selection algorithm. See the comments at the top of
+// lib/CodeGen/SelectionDAG/FastISel.cpp for background.
 //
-// This instruction selection method is designed to emit very poor code
-// quickly. Also, it is not designed to do much lowering, so most illegal
-// types (e.g. i64 on 32-bit targets) and operations (e.g. calls) are not
-// supported and cannot easily be added. Blocks containing operations
-// that are not supported need to be handled by a more capable selector,
-// such as the SelectionDAG selector.
+// This file scans through the target's tablegen instruction-info files
+// and extracts instructions with obvious-looking patterns, and it emits
+// code to look up these instructions by type and operator.
 //
-// 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.
-//
-// If compile time is so important, you might wonder why we don't just
-// skip codegen all-together, emit LLVM bytecode files, and execute them
-// with an interpreter. The answer is that it would complicate linking and
-// debugging, and also because that isn't how a compiler is expected to
-// work in some circles.
-//
-// If you need better generated code or more lowering than what this
-// instruction selector provides, use the SelectionDAG (DAGISel) instruction
-// selector instead. If you're looking here because SelectionDAG isn't fast
-// enough, consider looking into improving the SelectionDAG infastructure
-// instead. At the time of this writing there remain several major
-// opportunities for improvement.
-// 
 //===----------------------------------------------------------------------===//
 
 #include "FastISelEmitter.h"
@@ -89,7 +71,7 @@ struct OperandsSignature {
     for (unsigned i = 0, e = InstPatNode->getNumChildren(); i != e; ++i) {
       TreePatternNode *Op = InstPatNode->getChild(i);
       // For now, filter out any operand with a predicate.
-      if (!Op->getPredicateFn().empty())
+      if (!Op->getPredicateFns().empty())
         return false;
       // For now, filter out any operand with multiple values.
       if (Op->getExtTypes().size() != 1)
@@ -327,7 +309,7 @@ void FastISelMap::CollectPatterns(CodeGenDAGPatterns &CGP) {
       continue;
 
     // For now, filter out any instructions with predicates.
-    if (!InstPatNode->getPredicateFn().empty())
+    if (!InstPatNode->getPredicateFns().empty())
       continue;
 
     // Check all the operands.