Fix PR1817.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44284 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index e8cd867..c8df412 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -3463,7 +3463,12 @@
LHSCC != ICmpInst::ICMP_UGE && LHSCC != ICmpInst::ICMP_ULE &&
RHSCC != ICmpInst::ICMP_UGE && RHSCC != ICmpInst::ICMP_ULE &&
LHSCC != ICmpInst::ICMP_SGE && LHSCC != ICmpInst::ICMP_SLE &&
- RHSCC != ICmpInst::ICMP_SGE && RHSCC != ICmpInst::ICMP_SLE) {
+ RHSCC != ICmpInst::ICMP_SGE && RHSCC != ICmpInst::ICMP_SLE &&
+
+ // Don't try to fold ICMP_SLT + ICMP_ULT.
+ (ICmpInst::isEquality(LHSCC) || ICmpInst::isEquality(RHSCC) ||
+ ICmpInst::isSignedPredicate(LHSCC) ==
+ ICmpInst::isSignedPredicate(RHSCC))) {
// Ensure that the larger constant is on the RHS.
ICmpInst::Predicate GT = ICmpInst::isSignedPredicate(LHSCC) ?
ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;