[SelectionDAG] Split float and integer isKnownNeverZero tests

Splits off isKnownNeverZeroFloat to handle +/- 0 float cases.

This will make it easier to be more aggressive with the integer isKnownNeverZero tests (similar to ValueTracking), use computeKnownBits etc.

Differential Revision: https://reviews.llvm.org/D48969

llvm-svn: 336492

1 files changed, 11 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 20c0c35332e..1abc8c99efd 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -3611,10 +3611,20 @@ bool SelectionDAG::isKnownNeverNaN(SDValue Op) const {
   return false;
 }
 
-bool SelectionDAG::isKnownNeverZero(SDValue Op) const {
+bool SelectionDAG::isKnownNeverZeroFloat(SDValue Op) const {
+  assert(Op.getValueType().isFloatingPoint() &&
+         "Floating point type expected");
+
   // If the value is a constant, we can obviously see if it is a zero or not.
+  // TODO: Add BuildVector support.
   if (const ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(Op))
     return !C->isZero();
+  return false;
+}
+
+bool SelectionDAG::isKnownNeverZero(SDValue Op) const {
+  assert(!Op.getValueType().isFloatingPoint() &&
+         "Floating point types unsupported - use isKnownNeverZeroFloat");
 
   // TODO: Recognize more cases here.
   switch (Op.getOpcode()) {