Fix folding of icmp's of i1 where the comparison is signed. The code

was using the algorithm for folding unsigned comparisons which is
completely wrong.  This has been broken since the signless types change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53444 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 22 insertions, 10 deletions

diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 8cc7c05425..409d29c2a4 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -5196,34 +5196,46 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
   if (Ty == Type::Int1Ty) {
     switch (I.getPredicate()) {
     default: assert(0 && "Invalid icmp instruction!");
-    case ICmpInst::ICMP_EQ: {               // icmp eq bool %A, %B -> ~(A^B)
+    case ICmpInst::ICMP_EQ: {               // icmp eq i1 A, B -> ~(A^B)
       Instruction *Xor = BinaryOperator::CreateXor(Op0, Op1, I.getName()+"tmp");
       InsertNewInstBefore(Xor, I);
       return BinaryOperator::CreateNot(Xor);
     }
-    case ICmpInst::ICMP_NE:                  // icmp eq bool %A, %B -> A^B
+    case ICmpInst::ICMP_NE:                  // icmp eq i1 A, B -> A^B
       return BinaryOperator::CreateXor(Op0, Op1);
 
     case ICmpInst::ICMP_UGT:
-    case ICmpInst::ICMP_SGT:
-      std::swap(Op0, Op1);                   // Change icmp gt -> icmp lt
+      std::swap(Op0, Op1);                   // Change icmp ugt -> icmp ult
       // FALL THROUGH
-    case ICmpInst::ICMP_ULT:
-    case ICmpInst::ICMP_SLT: {               // icmp lt bool A, B -> ~X & Y
+    case ICmpInst::ICMP_ULT:{               // icmp ult i1 A, B -> ~A & B
       Instruction *Not = BinaryOperator::CreateNot(Op0, I.getName()+"tmp");
       InsertNewInstBefore(Not, I);
       return BinaryOperator::CreateAnd(Not, Op1);
     }
+    case ICmpInst::ICMP_SGT:
+      std::swap(Op0, Op1);                   // Change icmp sgt -> icmp slt
+      // FALL THROUGH
+    case ICmpInst::ICMP_SLT: {               // icmp slt i1 A, B -> A & ~B
+      Instruction *Not = BinaryOperator::CreateNot(Op1, I.getName()+"tmp");
+      InsertNewInstBefore(Not, I);
+      return BinaryOperator::CreateAnd(Not, Op0);
+    }
     case ICmpInst::ICMP_UGE:
-    case ICmpInst::ICMP_SGE:
-      std::swap(Op0, Op1);                   // Change icmp ge -> icmp le
+      std::swap(Op0, Op1);                   // Change icmp uge -> icmp ule
       // FALL THROUGH
-    case ICmpInst::ICMP_ULE:
-    case ICmpInst::ICMP_SLE: {               //  icmp le bool %A, %B -> ~A | B
+    case ICmpInst::ICMP_ULE: {               //  icmp ule i1 A, B -> ~A | B
       Instruction *Not = BinaryOperator::CreateNot(Op0, I.getName()+"tmp");
       InsertNewInstBefore(Not, I);
       return BinaryOperator::CreateOr(Not, Op1);
     }
+    case ICmpInst::ICMP_SGE:
+      std::swap(Op0, Op1);                   // Change icmp sge -> icmp sle
+      // FALL THROUGH
+    case ICmpInst::ICMP_SLE: {               //  icmp sle i1 A, B -> A | ~B
+      Instruction *Not = BinaryOperator::CreateNot(Op1, I.getName()+"tmp");
+      InsertNewInstBefore(Not, I);
+      return BinaryOperator::CreateOr(Not, Op0);
+    }
     }
   }