[ConstantRange] Add isAllNegative() and isAllNonNegative() methods

Add isAllNegative() and isAllNonNegative() methods to ConstantRange,
which determine whether all values in the constant range are
negative/non-negative.

This is useful for replacing KnownBits isNegative() and isNonNegative()
calls when changing code to use constant ranges.

Differential Revision: https://reviews.llvm.org/D60264

llvm-svn: 357871

1 files changed, 15 insertions, 0 deletions

diff --git a/llvm/lib/IR/ConstantRange.cpp b/llvm/lib/IR/ConstantRange.cpp
index f07ec9d5a3f..d048b8c2ed5 100644
--- a/llvm/lib/IR/ConstantRange.cpp
+++ b/llvm/lib/IR/ConstantRange.cpp
@@ -389,6 +389,21 @@ ConstantRange::isSizeLargerThan(uint64_t MaxSize) const {
   return (Upper - Lower).ugt(MaxSize);
 }
 
+bool ConstantRange::isAllNegative() const {
+  // Empty set is all negative, full set is not.
+  if (isEmptySet())
+    return true;
+  if (isFullSet())
+    return false;
+
+  return !isUpperSignWrapped() && !Upper.isStrictlyPositive();
+}
+
+bool ConstantRange::isAllNonNegative() const {
+  // Empty and full set are automatically treated correctly.
+  return !isSignWrappedSet() && Lower.isNonNegative();
+}
+
 APInt ConstantRange::getUnsignedMax() const {
   if (isFullSet() || isUpperWrapped())
     return APInt::getMaxValue(getBitWidth());