Split SelectionDAGISel::IsLegalAndProfitableToFold to

IsLegalToFold and IsProfitableToFold. The generic version of the later simply checks whether the folding candidate has a single use.

This allows the target isel routines more flexibility in deciding whether folding makes sense. The specific case we are interested in is folding constant pool loads with multiple uses.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96255 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 4 deletions

diff --git a/utils/TableGen/DAGISelEmitter.cpp b/utils/TableGen/DAGISelEmitter.cpp
index 0eb06bb541..d2e260e2e7 100644
--- a/utils/TableGen/DAGISelEmitter.cpp
+++ b/utils/TableGen/DAGISelEmitter.cpp
@@ -566,8 +566,11 @@ void PatternCodeEmitter::EmitMatchCode(TreePatternNode *N, TreePatternNode *P,
     if (NodeHasChain)
       OpNo = 1;
     if (!isRoot) {
-      // Multiple uses of actual result?
-      emitCheck(getValueName(RootName) + ".hasOneUse()");
+      // 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)");
       EmittedUseCheck = true;
       if (NodeHasChain) {
         // If the immediate use can somehow reach this node through another
@@ -597,8 +600,7 @@ void PatternCodeEmitter::EmitMatchCode(TreePatternNode *N, TreePatternNode *P,
         }
         
         if (NeedCheck) {
-          std::string ParentName(RootName.begin(), RootName.end()-1);
-          emitCheck("IsLegalAndProfitableToFold(" + getNodeName(RootName) +
+          emitCheck("IsLegalToFold(" + getValueName(RootName) +
                     ", " + getNodeName(ParentName) + ", N)");
         }
       }