At top of generated isel SelectCode() is this:
if (!N.Val->hasOneUse()) {
std::map<SDOperand, SDOperand>::iterator CGMI = CodeGenMap.find(N);
if (CGMI != CodeGenMap.end()) return CGMI->second;
}
Suppose a DAG like this:
X
^ ^
/ \
USE1 USE2
Suppose USE1 is being selected first and during which X is selected and
returned a new node. After this, USE1 is no longer an use of X. During USE2
selection, X will be selected again since it has only one use!
The fix is to always query CodeGenMap.
llvm-svn: 24679
diff --git a/llvm/utils/TableGen/DAGISelEmitter.cpp b/llvm/utils/TableGen/DAGISelEmitter.cpp
index bcb28a6..0a8b989 100644
--- a/llvm/utils/TableGen/DAGISelEmitter.cpp
+++ b/llvm/utils/TableGen/DAGISelEmitter.cpp
@@ -2234,10 +2234,8 @@
<< " N.getOpcode() < (ISD::BUILTIN_OP_END+" << InstNS
<< "INSTRUCTION_LIST_END))\n"
<< " return N; // Already selected.\n\n"
- << " if (!N.Val->hasOneUse()) {\n"
- << " std::map<SDOperand, SDOperand>::iterator CGMI = CodeGenMap.find(N);\n"
- << " if (CGMI != CodeGenMap.end()) return CGMI->second;\n"
- << " }\n"
+ << " std::map<SDOperand, SDOperand>::iterator CGMI = CodeGenMap.find(N);\n"
+ << " if (CGMI != CodeGenMap.end()) return CGMI->second;\n"
<< " switch (N.getOpcode()) {\n"
<< " default: break;\n"
<< " case ISD::EntryToken: // These leaves remain the same.\n"