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

diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 8cc7c05425b953d4f7d53573c25704f7bc6b5c3c..409d29c2a49cbd3967a2e6044ad64c574cdea3f2 100644 (file)
--- 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);
+    }
     }
   }
 

diff --git a/test/Transforms/InstCombine/2008-07-10-CastSextBool.ll b/test/Transforms/InstCombine/2008-07-10-CastSextBool.ll
index f5efefb0a0be48c7895ce4878d9e51031ce5da1f..205e57d797384aa85cf9d46bdea9eb27747f6381 100644 (file)
--- a/test/Transforms/InstCombine/2008-07-10-CastSextBool.ll
+++ b/test/Transforms/InstCombine/2008-07-10-CastSextBool.ll
@@ -1,8 +1,17 @@
 ; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {%C = xor i1 %A, true}
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {ret i1 false}
 ; PR2539
 
-define i1 @test(i1 %A) {
+define i1 @test1(i1 %A) {
        %B = zext i1 %A to i32
        %C = icmp slt i32 %B, 1
        ret i1 %C
 }
+
+
+define i1 @test2(i1 zeroext  %b) {
+entry:
+       %cmptmp = icmp slt i1 %b, true          ; <i1> [#uses=1]
+       ret i1 %cmptmp
+}
+