Fix InstCombine/2007-10-31-RangeCrash.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43596 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 56786b8..12523cd 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -4028,6 +4028,10 @@
case ICmpInst::ICMP_EQ: // (X u< 13 | X == 14) -> no change
break;
case ICmpInst::ICMP_UGT: // (X u< 13 | X u> 15) ->(X-13) u> 2
+ // If RHSCst is [us]MAXINT, it is always false. Not handling
+ // this can cause overflow.
+ if (RHSCst->isMaxValue(false))
+ return ReplaceInstUsesWith(I, LHS);
return InsertRangeTest(LHSVal, LHSCst, AddOne(RHSCst), false,
false, I);
case ICmpInst::ICMP_SGT: // (X u< 13 | X s> 15) -> no change
@@ -4045,6 +4049,10 @@
case ICmpInst::ICMP_EQ: // (X s< 13 | X == 14) -> no change
break;
case ICmpInst::ICMP_SGT: // (X s< 13 | X s> 15) ->(X-13) s> 2
+ // If RHSCst is [us]MAXINT, it is always false. Not handling
+ // this can cause overflow.
+ if (RHSCst->isMaxValue(true))
+ return ReplaceInstUsesWith(I, LHS);
return InsertRangeTest(LHSVal, LHSCst, AddOne(RHSCst), true,
false, I);
case ICmpInst::ICMP_UGT: // (X s< 13 | X u> 15) -> no change