fold trivial token factor nodes. This allows us to compile
test/CodeGen/X86/fp-stack-ret.ll into:
movl 4(%esp), %eax
fldl (%eax)
ret
instead of:
subl $12, %esp
movl 16(%esp), %eax
movsd (%eax), %xmm0
movsd %xmm0, (%esp)
fldl (%esp)
addl $12, %esp
ret
by eliminating a token factor that blocked a check.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34584 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 23a66f5..2679a8c 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1351,6 +1351,12 @@
// Fold operations.
switch (Opcode) {
+ case ISD::TokenFactor:
+ // Fold trivial token factors.
+ if (N1.getOpcode() == ISD::EntryToken) return N2;
+ if (N2.getOpcode() == ISD::EntryToken) return N1;
+ break;
+
case ISD::AND:
// (X & 0) -> 0. This commonly occurs when legalizing i64 values, so it's
// worth handling here.