[ConstantRange] Handle wrapping ranges in min/max (PR48643)

When one of the inputs is a wrapping range, intersect with the
union of the two inputs. The union of the two inputs corresponds
to the result we would get if we treated the min/max as a simple
select.

This fixes PR48643.

1 files changed, 16 insertions, 4 deletions

diff --git a/llvm/lib/IR/ConstantRange.cpp b/llvm/lib/IR/ConstantRange.cpp
index 275996d..4dbe1a1 100644
--- a/llvm/lib/IR/ConstantRange.cpp
+++ b/llvm/lib/IR/ConstantRange.cpp
@@ -1058,7 +1058,10 @@ ConstantRange::smax(const ConstantRange &Other) const {
     return getEmpty();
   APInt NewL = APIntOps::smax(getSignedMin(), Other.getSignedMin());
   APInt NewU = APIntOps::smax(getSignedMax(), Other.getSignedMax()) + 1;
-  return getNonEmpty(std::move(NewL), std::move(NewU));
+  ConstantRange Res = getNonEmpty(std::move(NewL), std::move(NewU));
+  if (isSignWrappedSet() || Other.isSignWrappedSet())
+    return Res.intersectWith(unionWith(Other, Signed), Signed);
+  return Res;
 }
 
 ConstantRange
@@ -1069,7 +1072,10 @@ ConstantRange::umax(const ConstantRange &Other) const {
     return getEmpty();
   APInt NewL = APIntOps::umax(getUnsignedMin(), Other.getUnsignedMin());
   APInt NewU = APIntOps::umax(getUnsignedMax(), Other.getUnsignedMax()) + 1;
-  return getNonEmpty(std::move(NewL), std::move(NewU));
+  ConstantRange Res = getNonEmpty(std::move(NewL), std::move(NewU));
+  if (isWrappedSet() || Other.isWrappedSet())
+    return Res.intersectWith(unionWith(Other, Unsigned), Unsigned);
+  return Res;
 }
 
 ConstantRange
@@ -1080,7 +1086,10 @@ ConstantRange::smin(const ConstantRange &Other) const {
     return getEmpty();
   APInt NewL = APIntOps::smin(getSignedMin(), Other.getSignedMin());
   APInt NewU = APIntOps::smin(getSignedMax(), Other.getSignedMax()) + 1;
-  return getNonEmpty(std::move(NewL), std::move(NewU));
+  ConstantRange Res = getNonEmpty(std::move(NewL), std::move(NewU));
+  if (isSignWrappedSet() || Other.isSignWrappedSet())
+    return Res.intersectWith(unionWith(Other, Signed), Signed);
+  return Res;
 }
 
 ConstantRange
@@ -1091,7 +1100,10 @@ ConstantRange::umin(const ConstantRange &Other) const {
     return getEmpty();
   APInt NewL = APIntOps::umin(getUnsignedMin(), Other.getUnsignedMin());
   APInt NewU = APIntOps::umin(getUnsignedMax(), Other.getUnsignedMax()) + 1;
-  return getNonEmpty(std::move(NewL), std::move(NewU));
+  ConstantRange Res = getNonEmpty(std::move(NewL), std::move(NewU));
+  if (isWrappedSet() || Other.isWrappedSet())
+    return Res.intersectWith(unionWith(Other, Unsigned), Unsigned);
+  return Res;
 }
 
 ConstantRange