Apply constraints

Author: leewei05

llvm/lib/Transforms/Scalar/ConstraintElimination.cpp

@@ -562,6 +562,18 @@ static Decomposition decompose(Value *V,
       }
     }
 
+    // (x | y) < 0 => (x < 0) || (y < 0)
+    if (match(V, m_Or(m_Value(Op0), m_Value(Op1)))) {
+      if (!isKnownNonNegative(Op0, DL) || !isKnownNonNegative(Op1, DL))
+        return MergeResults(Op0, Op1, IsSigned);
+    }
+
+    // (x & y) < 0 => (x < 0) && (y < 0)
+    if (match(V, m_And(m_Value(Op0), m_Value(Op1)))) {
+      if (!isKnownNonNegative(Op0, DL) && !isKnownNonNegative(Op1, DL))
+        return MergeResults(Op0, Op1, IsSigned);
+    }
+
     return {V, IsKnownNonNegative};
   }
 

llvm/test/Transforms/ConstraintElimination/and.ll

@@ -613,13 +613,13 @@ define void @test_decompose_bitwise_and(i4 %x, i4 %y) {
 ; CHECK:       bb1:
 ; CHECK-NEXT:    [[F_1:%.*]] = icmp sge i4 [[X]], 0
 ; CHECK-NEXT:    [[F_2:%.*]] = icmp sge i4 [[Y]], 0
-; CHECK-NEXT:    [[F_AND:%.*]] = and i1 [[F_1]], [[F_2]]
+; CHECK-NEXT:    [[F_AND:%.*]] = and i1 false, [[F_2]]
 ; CHECK-NEXT:    call void @use(i1 [[F_AND]])
 ; CHECK-NEXT:    ret void
 ; CHECK:       exit:
 ; CHECK-NEXT:    [[F_3:%.*]] = icmp slt i4 [[X]], 0
 ; CHECK-NEXT:    [[F_4:%.*]] = icmp slt i4 [[Y]], 0
-; CHECK-NEXT:    [[F_AND_2:%.*]] = and i1 [[F_3]], [[F_4]]
+; CHECK-NEXT:    [[F_AND_2:%.*]] = and i1 false, [[F_4]]
 ; CHECK-NEXT:    call void @use(i1 [[F_AND_2]])
 ; CHECK-NEXT:    ret void
 ;
@@ -655,15 +655,15 @@ define void @test_decompose_nested_bitwise_and(i4 %x, i4 %y, i4 %z) {
 ; CHECK-NEXT:    [[F_2:%.*]] = icmp sge i4 [[Y]], 0
 ; CHECK-NEXT:    [[F_3:%.*]] = icmp sge i4 [[Z]], 0
 ; CHECK-NEXT:    [[F_AND:%.*]] = and i1 [[F_1]], [[F_2]]
-; CHECK-NEXT:    [[F_AND_2:%.*]] = and i1 [[F_AND]], [[F_3]]
+; CHECK-NEXT:    [[F_AND_2:%.*]] = and i1 [[F_AND]], false
 ; CHECK-NEXT:    call void @use(i1 [[F_AND]])
 ; CHECK-NEXT:    ret void
 ; CHECK:       exit:
 ; CHECK-NEXT:    [[F_4:%.*]] = icmp slt i4 [[X]], 0
 ; CHECK-NEXT:    [[F_5:%.*]] = icmp slt i4 [[Y]], 0
 ; CHECK-NEXT:    [[F_6:%.*]] = icmp slt i4 [[Z]], 0
 ; CHECK-NEXT:    [[F_AND_3:%.*]] = and i1 [[F_4]], [[F_5]]
-; CHECK-NEXT:    [[F_AND_4:%.*]] = and i1 [[F_AND_3]], [[F_6]]
+; CHECK-NEXT:    [[F_AND_4:%.*]] = and i1 [[F_AND_3]], false
 ; CHECK-NEXT:    call void @use(i1 [[F_AND_4]])
 ; CHECK-NEXT:    ret void
 ;

llvm/test/Transforms/ConstraintElimination/or.ll

@@ -818,13 +818,13 @@ define void @test_decompose_bitwise_or(i4 %x, i4 %y) {
 ; CHECK:       bb1:
 ; CHECK-NEXT:    [[F_1:%.*]] = icmp slt i4 [[X]], 0
 ; CHECK-NEXT:    [[F_2:%.*]] = icmp slt i4 [[Y]], 0
-; CHECK-NEXT:    [[F_OR:%.*]] = or i1 [[F_1]], [[F_2]]
+; CHECK-NEXT:    [[F_OR:%.*]] = or i1 true, [[F_2]]
 ; CHECK-NEXT:    call void @use(i1 [[F_OR]])
 ; CHECK-NEXT:    ret void
 ; CHECK:       exit:
 ; CHECK-NEXT:    [[F_3:%.*]] = icmp sge i4 [[X]], 0
 ; CHECK-NEXT:    [[F_4:%.*]] = icmp sge i4 [[Y]], 0
-; CHECK-NEXT:    [[F_OR_2:%.*]] = or i1 [[F_3]], [[F_4]]
+; CHECK-NEXT:    [[F_OR_2:%.*]] = or i1 true, [[F_4]]
 ; CHECK-NEXT:    call void @use(i1 [[F_OR_2]])
 ; CHECK-NEXT:    ret void
 ;
@@ -860,15 +860,15 @@ define void @test_decompose_nested_bitwise_or(i4 %x, i4 %y, i4 %z) {
 ; CHECK-NEXT:    [[F_2:%.*]] = icmp slt i4 [[Y]], 0
 ; CHECK-NEXT:    [[F_3:%.*]] = icmp slt i4 [[Z]], 0
 ; CHECK-NEXT:    [[F_OR:%.*]] = or i1 [[F_1]], [[F_2]]
-; CHECK-NEXT:    [[F_OR_2:%.*]] = or i1 [[F_OR]], [[F_3]]
+; CHECK-NEXT:    [[F_OR_2:%.*]] = or i1 [[F_OR]], true
 ; CHECK-NEXT:    call void @use(i1 [[F_OR_2]])
 ; CHECK-NEXT:    ret void
 ; CHECK:       exit:
 ; CHECK-NEXT:    [[F_4:%.*]] = icmp sge i4 [[X]], 0
 ; CHECK-NEXT:    [[F_5:%.*]] = icmp sge i4 [[Y]], 0
 ; CHECK-NEXT:    [[F_6:%.*]] = icmp sge i4 [[Z]], 0
 ; CHECK-NEXT:    [[F_OR_3:%.*]] = or i1 [[F_4]], [[F_5]]
-; CHECK-NEXT:    [[F_OR_4:%.*]] = or i1 [[F_OR_3]], [[F_6]]
+; CHECK-NEXT:    [[F_OR_4:%.*]] = or i1 [[F_OR_3]], true
 ; CHECK-NEXT:    call void @use(i1 [[F_OR_4]])
 ; CHECK-NEXT:    ret void
 ;