Fix optimisations of SELECT_CC which assumed result is boolean
Some optimisations in DAGCombiner cause miscompilations for targets that use
TargetLowering::UndefinedBooleanContent, because they assume that the results
of a SELECT_CC node are boolean values, and can be safely ANDed, ORed and
XORed. These optimisations are only valid for targets that use
ZeroOrOneBooleanContent or ZeroOrNegativeOneBooleanContent.
This is a follow-up to D6210/r221693.
llvm-svn: 222123
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 342a427..709406a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -645,6 +645,10 @@
!TLI.isConstFalseVal(N.getOperand(3).getNode()))
return false;
+ if (TLI.getBooleanContents(N.getValueType()) ==
+ TargetLowering::UndefinedBooleanContent)
+ return false;
+
LHS = N.getOperand(0);
RHS = N.getOperand(1);
CC = N.getOperand(4);
@@ -3826,8 +3830,7 @@
return RXOR;
// fold !(x cc y) -> (x !cc y)
- if (N1C && N1C->getAPIntValue().isAllOnesValue() &&
- isSetCCEquivalent(N0, LHS, RHS, CC)) {
+ if (TLI.isConstTrueVal(N1.getNode()) && isSetCCEquivalent(N0, LHS, RHS, CC)) {
bool isInt = LHS.getValueType().isInteger();
ISD::CondCode NotCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(),
isInt);