6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-14 11:32:34 +00:00
Code Issues Projects Releases Wiki Activity

change dag isel emitter to only call 'IsProfitableToFold' on nodes

Browse Source 
with chains.  On interior nodes that lead up to them, we just directly
check that there is a single use.  This generates slightly more
efficient code.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96366 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2010-02-16 19:03:34 +00:00
parent 1665b0a224
commit 29c6270328
1 changed files with 13 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
utils/TableGen/DAGISelEmitter.cpp
View File

@ -568,9 +568,12 @@ void PatternCodeEmitter::EmitMatchCode(TreePatternNode *N, TreePatternNode *P,
// Check if it's profitable to fold the node. e.g. Check for multiple uses
// of actual result?
std::string ParentName(RootName.begin(), RootName.end()-1);
emitCheck("IsProfitableToFold(" + getValueName(RootName) +
", " + getNodeName(ParentName) + ", N)");
if (NodeHasChain) {
if (!NodeHasChain) {
// If this is just an interior node, check to see if it has a single
// use. If the node has multiple uses and the pattern has a load as
// an operand, then we can't fold the load.
emitCheck(getValueName(RootName) + ".hasOneUse()");
} else {
// If the immediate use can somehow reach this node through another
// path, then can't fold it either or it will create a cycle.
// e.g. In the following diagram, XX can reach ld through YY. If
@ -588,6 +591,8 @@ void PatternCodeEmitter::EmitMatchCode(TreePatternNode *N, TreePatternNode *P,
// We know we need the check if N's parent is not the root.
bool NeedCheck = P != Pattern;
if (!NeedCheck) {
// If the parent is the root and the node has more than one operand,
// we need to check.
const SDNodeInfo &PInfo = CGP.getSDNodeInfo(P->getOperator());
NeedCheck =
P->getOperator() == CGP.get_intrinsic_void_sdnode() ||
@ -600,8 +605,13 @@ void PatternCodeEmitter::EmitMatchCode(TreePatternNode *N, TreePatternNode *P,
}
if (NeedCheck) {
emitCheck("IsProfitableToFold(" + getValueName(RootName) +
", " + getNodeName(ParentName) + ", N)");
emitCheck("IsLegalToFold(" + getValueName(RootName) +
", " + getNodeName(ParentName) + ", N)");
} else {
// Otherwise, just verify that the node only has a single use.
emitCheck(getValueName(RootName) + ".hasOneUse()");
}
}
}