[llvm] r269831 - [InstCombine] add another test for wrong icmp constant (PR27792)

[Sanjay Patel via llvm-commits]

Author: spatel
Date: Tue May 17 15:20:40 2016
New Revision: 269831

URL: http://llvm.org/viewvc/llvm-project?rev=269831&view=rev
Log:
[InstCombine] add another test for wrong icmp constant (PR27792)

It doesn't matter if the comparison is unsigned; the inc/dec is always signed.


Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
    llvm/trunk/test/Transforms/InstCombine/icmp.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=269831&r1=269830&r2=269831&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Tue May 17 15:20:40 2016
@@ -3150,7 +3150,7 @@ static ICmpInst *canonicalizeCmpWithCons
 
   // Increment or decrement the constant and set the new comparison predicate:
   // ULE -> ULT ; UGE -> UGT ; SLE -> SLT ; SGE -> SGT
-  Constant *OneOrNegOne = ConstantInt::get(Op1Type, IsLE ? 1 : -1, IsSigned);
+  Constant *OneOrNegOne = ConstantInt::get(Op1Type, IsLE ? 1 : -1, true);
   CmpInst::Predicate NewPred = IsLE ? ICmpInst::ICMP_ULT: ICmpInst::ICMP_UGT;
   NewPred = IsSigned ? ICmpInst::getSignedPredicate(NewPred) : NewPred;
   return new ICmpInst(NewPred, Op0, ConstantExpr::getAdd(Op1C, OneOrNegOne));

Modified: llvm/trunk/test/Transforms/InstCombine/icmp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/icmp.ll?rev=269831&r1=269830&r2=269831&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/icmp.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/icmp.ll Tue May 17 15:20:40 2016
@@ -2098,7 +2098,7 @@ return:
   ret void
 }
 
-; When canonicalizing to 'sgt', make sure the constant is correct.
+; When canonicalizing to 'gt/lt', make sure the constant is correct.
 
 define i1 @PR27792(i128 %a) {
 ; CHECK-LABEL: @PR27792(
@@ -2109,3 +2109,12 @@ define i1 @PR27792(i128 %a) {
   ret i1 %cmp
 }
 
+define i1 @PR27792_2(i128 %a) {
+; CHECK-LABEL: @PR27792_2(
+; CHECK-NEXT:    [[B:%.*]] = icmp ne i128 %a, 0
+; CHECK-NEXT:    ret i1 [[B]]
+;
+  %b = icmp uge i128 %a, 1
+  ret i1 %b
+}
+