[InstCombine] Drop samesign in foldLogOpOfMaskedICmps

Author: dtcxzyw

llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp

@@ -610,8 +610,11 @@ static Value *foldLogOpOfMaskedICmps(Value *LHS, Value *RHS, bool IsAnd,
       APInt NewMask = *ConstB & *ConstD;
       if (NewMask == *ConstB)
         return LHS;
-      if (NewMask == *ConstD)
+      if (NewMask == *ConstD) {
+        if (IsLogical)
+          cast<ICmpInst>(RHS)->setSameSign(false);
         return RHS;
+      }
     }
 
     if (Mask & AMask_NotAllOnes) {

llvm/test/Transforms/InstCombine/sign-test-and-or.ll

@@ -351,7 +351,7 @@ define i1 @test9_logical(i32 %a) {
 
 define i1 @test9_logical_samesign(i32 %a) {
 ; CHECK-LABEL: @test9_logical_samesign(
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp samesign sgt i32 [[A:%.*]], -1
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp sgt i32 [[A:%.*]], -1
 ; CHECK-NEXT:    ret i1 [[CMP2]]
 ;
   %masked = and i32 %a, -1073741825
@@ -363,7 +363,7 @@ define i1 @test9_logical_samesign(i32 %a) {
 
 define i1 @test_logical_or_icmp_icmp_samesign(i32 %a) {
 ; CHECK-LABEL: @test_logical_or_icmp_icmp_samesign(
-; CHECK-NEXT:    [[CMP2:%.*]] = icmp samesign sgt i32 [[A:%.*]], -1
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp sgt i32 [[A:%.*]], -1
 ; CHECK-NEXT:    ret i1 [[CMP2]]
 ;
   %cmp1 = icmp eq i32 %a, 0