%t2 = sub <2 x i4> %y, %t1
ret <2 x i4> %t2
}
+
+; zext of non-negative can be negated
+; sext of non-positive can be negated
+define i16 @negation_of_zeroext_of_nonnegative(i8 %x) {
+; CHECK-LABEL: @negation_of_zeroext_of_nonnegative(
+; CHECK-NEXT: [[T0:%.*]] = sub i8 0, [[X:%.*]]
+; CHECK-NEXT: [[T1:%.*]] = icmp sgt i8 [[T0]], -1
+; CHECK-NEXT: br i1 [[T1]], label [[NONNEG_BB:%.*]], label [[NEG_BB:%.*]]
+; CHECK: nonneg_bb:
+; CHECK-NEXT: [[T2:%.*]] = zext i8 [[T0]] to i16
+; CHECK-NEXT: [[T3:%.*]] = sub nsw i16 0, [[T2]]
+; CHECK-NEXT: ret i16 [[T3]]
+; CHECK: neg_bb:
+; CHECK-NEXT: ret i16 0
+;
+ %t0 = sub i8 0, %x
+ %t1 = icmp sge i8 %t0, 0
+ br i1 %t1, label %nonneg_bb, label %neg_bb
+
+nonneg_bb:
+ %t2 = zext i8 %t0 to i16
+ %t3 = sub i16 0, %t2
+ ret i16 %t3
+
+neg_bb:
+ ret i16 0
+}
+define i16 @negation_of_zeroext_of_positive(i8 %x) {
+; CHECK-LABEL: @negation_of_zeroext_of_positive(
+; CHECK-NEXT: [[T0:%.*]] = sub i8 0, [[X:%.*]]
+; CHECK-NEXT: [[T1:%.*]] = icmp sgt i8 [[T0]], 0
+; CHECK-NEXT: br i1 [[T1]], label [[NONNEG_BB:%.*]], label [[NEG_BB:%.*]]
+; CHECK: nonneg_bb:
+; CHECK-NEXT: [[T2:%.*]] = zext i8 [[T0]] to i16
+; CHECK-NEXT: [[T3:%.*]] = sub nsw i16 0, [[T2]]
+; CHECK-NEXT: ret i16 [[T3]]
+; CHECK: neg_bb:
+; CHECK-NEXT: ret i16 0
+;
+ %t0 = sub i8 0, %x
+ %t1 = icmp sgt i8 %t0, 0
+ br i1 %t1, label %nonneg_bb, label %neg_bb
+
+nonneg_bb:
+ %t2 = zext i8 %t0 to i16
+ %t3 = sub i16 0, %t2
+ ret i16 %t3
+
+neg_bb:
+ ret i16 0
+}
+define i16 @negation_of_signext_of_negative(i8 %x) {
+; CHECK-LABEL: @negation_of_signext_of_negative(
+; CHECK-NEXT: [[T0:%.*]] = sub i8 0, [[X:%.*]]
+; CHECK-NEXT: [[T1:%.*]] = icmp slt i8 [[T0]], 0
+; CHECK-NEXT: br i1 [[T1]], label [[NEG_BB:%.*]], label [[NONNEG_BB:%.*]]
+; CHECK: neg_bb:
+; CHECK-NEXT: [[T2:%.*]] = sext i8 [[T0]] to i16
+; CHECK-NEXT: [[T3:%.*]] = sub nsw i16 0, [[T2]]
+; CHECK-NEXT: ret i16 [[T3]]
+; CHECK: nonneg_bb:
+; CHECK-NEXT: ret i16 0
+;
+ %t0 = sub i8 0, %x
+ %t1 = icmp slt i8 %t0, 0
+ br i1 %t1, label %neg_bb, label %nonneg_bb
+
+neg_bb:
+ %t2 = sext i8 %t0 to i16
+ %t3 = sub i16 0, %t2
+ ret i16 %t3
+
+nonneg_bb:
+ ret i16 0
+}
+define i16 @negation_of_signext_of_nonpositive(i8 %x) {
+; CHECK-LABEL: @negation_of_signext_of_nonpositive(
+; CHECK-NEXT: [[T0:%.*]] = sub i8 0, [[X:%.*]]
+; CHECK-NEXT: [[T1:%.*]] = icmp slt i8 [[T0]], 1
+; CHECK-NEXT: br i1 [[T1]], label [[NEG_BB:%.*]], label [[NONNEG_BB:%.*]]
+; CHECK: neg_bb:
+; CHECK-NEXT: [[T2:%.*]] = sext i8 [[T0]] to i16
+; CHECK-NEXT: [[T3:%.*]] = sub nsw i16 0, [[T2]]
+; CHECK-NEXT: ret i16 [[T3]]
+; CHECK: nonneg_bb:
+; CHECK-NEXT: ret i16 0
+;
+ %t0 = sub i8 0, %x
+ %t1 = icmp sle i8 %t0, 0
+ br i1 %t1, label %neg_bb, label %nonneg_bb
+
+neg_bb:
+ %t2 = sext i8 %t0 to i16
+ %t3 = sub i16 0, %t2
+ ret i16 %t3
+
+nonneg_bb:
+ ret i16 0
+}
+define i16 @negation_of_signext_of_nonnegative__wrong_cast(i8 %x) {
+; CHECK-LABEL: @negation_of_signext_of_nonnegative__wrong_cast(
+; CHECK-NEXT: [[T0:%.*]] = sub i8 0, [[X:%.*]]
+; CHECK-NEXT: [[T1:%.*]] = icmp sgt i8 [[T0]], -1
+; CHECK-NEXT: br i1 [[T1]], label [[NONNEG_BB:%.*]], label [[NEG_BB:%.*]]
+; CHECK: nonneg_bb:
+; CHECK-NEXT: [[T2:%.*]] = sext i8 [[T0]] to i16
+; CHECK-NEXT: [[T3:%.*]] = sub nsw i16 0, [[T2]]
+; CHECK-NEXT: ret i16 [[T3]]
+; CHECK: neg_bb:
+; CHECK-NEXT: ret i16 0
+;
+ %t0 = sub i8 0, %x
+ %t1 = icmp sge i8 %t0, 0
+ br i1 %t1, label %nonneg_bb, label %neg_bb
+
+nonneg_bb:
+ %t2 = sext i8 %t0 to i16
+ %t3 = sub i16 0, %t2
+ ret i16 %t3
+
+neg_bb:
+ ret i16 0
+}
+define i16 @negation_of_zeroext_of_negative_wrongcast(i8 %x) {
+; CHECK-LABEL: @negation_of_zeroext_of_negative_wrongcast(
+; CHECK-NEXT: [[T0:%.*]] = sub i8 0, [[X:%.*]]
+; CHECK-NEXT: [[T1:%.*]] = icmp slt i8 [[T0]], 0
+; CHECK-NEXT: br i1 [[T1]], label [[NEG_BB:%.*]], label [[NONNEG_BB:%.*]]
+; CHECK: neg_bb:
+; CHECK-NEXT: [[T2:%.*]] = zext i8 [[T0]] to i16
+; CHECK-NEXT: [[T3:%.*]] = sub nsw i16 0, [[T2]]
+; CHECK-NEXT: ret i16 [[T3]]
+; CHECK: nonneg_bb:
+; CHECK-NEXT: ret i16 0
+;
+ %t0 = sub i8 0, %x
+ %t1 = icmp slt i8 %t0, 0
+ br i1 %t1, label %neg_bb, label %nonneg_bb
+
+neg_bb:
+ %t2 = zext i8 %t0 to i16
+ %t3 = sub i16 0, %t2
+ ret i16 %t3
+
+nonneg_bb:
+ ret i16 0
+}