Add a few more simple fast-math constant propagations and cancellations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167200 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 23821e6..a83203b 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -5729,6 +5729,18 @@
DAG.getNode(ISD::FADD, N->getDebugLoc(), VT,
N0.getOperand(1), N1));
+ // If allow, fold (fadd (fneg x), x) -> 0.0
+ if (DAG.getTarget().Options.UnsafeFPMath &&
+ N0.getOpcode() == ISD::FNEG && N0.getOperand(0) == N1) {
+ return DAG.getConstantFP(0.0, VT);
+ }
+
+ // If allow, fold (fadd x, (fneg x)) -> 0.0
+ if (DAG.getTarget().Options.UnsafeFPMath &&
+ N1.getOpcode() == ISD::FNEG && N1.getOperand(0) == N0) {
+ return DAG.getConstantFP(0.0, VT);
+ }
+
// In unsafe math mode, we can fold chains of FADD's of the same value
// into multiplications. This transform is not safe in general because
// we are reducing the number of rounding steps.
@@ -6038,6 +6050,12 @@
EVT VT = N->getValueType(0);
DebugLoc dl = N->getDebugLoc();
+ if (DAG.getTarget().Options.UnsafeFPMath) {
+ if (N0CFP && N0CFP->isZero())
+ return N2;
+ if (N1CFP && N1CFP->isZero())
+ return N2;
+ }
if (N0CFP && N0CFP->isExactlyValue(1.0))
return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N1, N2);
if (N1CFP && N1CFP->isExactlyValue(1.0))