[ConstantRange] Add getNonEmpty() constructor
ConstantRanges have an annoying special case: If upper and lower are
the same, it can be either an empty or a full set. When constructing
constant ranges nearly always a full set is intended, but this still
requires an explicit check in many places.
This revision adds a getNonEmpty() constructor that disambiguates this
case: If upper and lower are the same, a full set is created.
Differential Revision: https://reviews.llvm.org/D60947
llvm-svn: 358854
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 9c7b0fa..3b08a2d 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -5726,8 +5726,7 @@
else if (auto *SI = dyn_cast<SelectInst>(V))
setLimitsForSelectPattern(*SI, Lower, Upper);
- ConstantRange CR = Lower != Upper ? ConstantRange(Lower, Upper)
- : ConstantRange::getFull(BitWidth);
+ ConstantRange CR = ConstantRange::getNonEmpty(Lower, Upper);
if (auto *I = dyn_cast<Instruction>(V))
if (auto *Range = IIQ.getMetadata(I, LLVMContext::MD_range))