1 files changed, 189 insertions, 0 deletions
diff --git a/llvm/test/Transforms/InstCombine/unsigned-add-lack-of-overflow-check-via-xor.ll b/llvm/test/Transforms/InstCombine/unsigned-add-lack-of-overflow-check-via-xor.ll
new file mode 100644
index 00000000000..f48bd6c9abc
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/unsigned-add-lack-of-overflow-check-via-xor.ll
@@ -0,0 +1,189 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt %s -instcombine -S | FileCheck %s
+
+; Should fold
+;   (%y ^ -1) u>= %x
+; to
+;   @llvm.uadd.with.overflow(%x, %y) + extractvalue + not
+;
+; All tests here have extra uses, to ensure that the pattern isn't perturbed.
+
+declare void @use8(i8)
+declare void @use2x8(<2 x i8>)
+
+define i1 @t0_basic(i8 %x, i8 %y) {
+; CHECK-LABEL: @t0_basic(
+; CHECK-NEXT:    [[T0:%.*]] = xor i8 [[Y:%.*]], -1
+; CHECK-NEXT:    call void @use8(i8 [[T0]])
+; CHECK-NEXT:    [[R:%.*]] = icmp uge i8 [[T0]], [[X:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = xor i8 %y, -1
+  call void @use8(i8 %t0)
+  %r = icmp uge i8 %t0, %x
+  ret i1 %r
+}
+
+define <2 x i1> @t1_vec(<2 x i8> %x, <2 x i8> %y) {
+; CHECK-LABEL: @t1_vec(
+; CHECK-NEXT:    [[T0:%.*]] = xor <2 x i8> [[Y:%.*]], <i8 -1, i8 -1>
+; CHECK-NEXT:    call void @use2x8(<2 x i8> [[T0]])
+; CHECK-NEXT:    [[R:%.*]] = icmp uge <2 x i8> [[T0]], [[X:%.*]]
+; CHECK-NEXT:    ret <2 x i1> [[R]]
+;
+  %t0 = xor <2 x i8> %y, <i8 -1, i8 -1>
+  call void @use2x8(<2 x i8> %t0)
+  %r = icmp uge <2 x i8> %t0, %x
+  ret <2 x i1> %r
+}
+
+; Commutativity
+
+declare i8 @gen8()
+
+define i1 @t2_commutative(i8 %y) {
+; CHECK-LABEL: @t2_commutative(
+; CHECK-NEXT:    [[T0:%.*]] = xor i8 [[Y:%.*]], -1
+; CHECK-NEXT:    call void @use8(i8 [[T0]])
+; CHECK-NEXT:    [[X:%.*]] = call i8 @gen8()
+; CHECK-NEXT:    [[R:%.*]] = icmp ule i8 [[X]], [[T0]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = xor i8 %y, -1
+  call void @use8(i8 %t0)
+  %x = call i8 @gen8()
+  %r = icmp ule i8 %x, %t0 ; swapped
+  ret i1 %r
+}
+
+; Extra-use tests
+
+define i1 @t3_no_extrause(i8 %x, i8 %y) {
+; CHECK-LABEL: @t3_no_extrause(
+; CHECK-NEXT:    [[T0:%.*]] = xor i8 [[Y:%.*]], -1
+; CHECK-NEXT:    [[R:%.*]] = icmp uge i8 [[T0]], [[X:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = xor i8 %y, -1
+  %r = icmp uge i8 %t0, %x
+  ret i1 %r
+}
+
+; Negative tests
+
+define i1 @n4_wrong_pred0(i8 %x, i8 %y) {
+; CHECK-LABEL: @n4_wrong_pred0(
+; CHECK-NEXT:    [[T0:%.*]] = xor i8 [[Y:%.*]], -1
+; CHECK-NEXT:    call void @use8(i8 [[T0]])
+; CHECK-NEXT:    [[R:%.*]] = icmp ule i8 [[T0]], [[X:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = xor i8 %y, -1
+  call void @use8(i8 %t0)
+  %r = icmp ule i8 %t0, %x
+  ret i1 %r
+}
+
+define i1 @n5_wrong_pred1(i8 %x, i8 %y) {
+; CHECK-LABEL: @n5_wrong_pred1(
+; CHECK-NEXT:    [[T0:%.*]] = xor i8 [[Y:%.*]], -1
+; CHECK-NEXT:    call void @use8(i8 [[T0]])
+; CHECK-NEXT:    [[R:%.*]] = icmp ugt i8 [[T0]], [[X:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = xor i8 %y, -1
+  call void @use8(i8 %t0)
+  %r = icmp ugt i8 %t0, %x
+  ret i1 %r
+}
+
+define i1 @n6_wrong_pred2(i8 %x, i8 %y) {
+; CHECK-LABEL: @n6_wrong_pred2(
+; CHECK-NEXT:    [[T0:%.*]] = xor i8 [[Y:%.*]], -1
+; CHECK-NEXT:    call void @use8(i8 [[T0]])
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[T0]], [[X:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = xor i8 %y, -1
+  call void @use8(i8 %t0)
+  %r = icmp eq i8 %t0, %x
+  ret i1 %r
+}
+
+define i1 @n7_wrong_pred3(i8 %x, i8 %y) {
+; CHECK-LABEL: @n7_wrong_pred3(
+; CHECK-NEXT:    [[T0:%.*]] = xor i8 [[Y:%.*]], -1
+; CHECK-NEXT:    call void @use8(i8 [[T0]])
+; CHECK-NEXT:    [[R:%.*]] = icmp ne i8 [[T0]], [[X:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = xor i8 %y, -1
+  call void @use8(i8 %t0)
+  %r = icmp ne i8 %t0, %x
+  ret i1 %r
+}
+
+define i1 @n8_wrong_pred4(i8 %x, i8 %y) {
+; CHECK-LABEL: @n8_wrong_pred4(
+; CHECK-NEXT:    [[T0:%.*]] = xor i8 [[Y:%.*]], -1
+; CHECK-NEXT:    call void @use8(i8 [[T0]])
+; CHECK-NEXT:    [[R:%.*]] = icmp slt i8 [[T0]], [[X:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = xor i8 %y, -1
+  call void @use8(i8 %t0)
+  %r = icmp slt i8 %t0, %x
+  ret i1 %r
+}
+
+define i1 @n9_wrong_pred5(i8 %x, i8 %y) {
+; CHECK-LABEL: @n9_wrong_pred5(
+; CHECK-NEXT:    [[T0:%.*]] = xor i8 [[Y:%.*]], -1
+; CHECK-NEXT:    call void @use8(i8 [[T0]])
+; CHECK-NEXT:    [[R:%.*]] = icmp sle i8 [[T0]], [[X:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = xor i8 %y, -1
+  call void @use8(i8 %t0)
+  %r = icmp sle i8 %t0, %x
+  ret i1 %r
+}
+
+define i1 @n10_wrong_pred6(i8 %x, i8 %y) {
+; CHECK-LABEL: @n10_wrong_pred6(
+; CHECK-NEXT:    [[T0:%.*]] = xor i8 [[Y:%.*]], -1
+; CHECK-NEXT:    call void @use8(i8 [[T0]])
+; CHECK-NEXT:    [[R:%.*]] = icmp sgt i8 [[T0]], [[X:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = xor i8 %y, -1
+  call void @use8(i8 %t0)
+  %r = icmp sgt i8 %t0, %x
+  ret i1 %r
+}
+
+define i1 @n11_wrong_pred7(i8 %x, i8 %y) {
+; CHECK-LABEL: @n11_wrong_pred7(
+; CHECK-NEXT:    [[T0:%.*]] = xor i8 [[Y:%.*]], -1
+; CHECK-NEXT:    call void @use8(i8 [[T0]])
+; CHECK-NEXT:    [[R:%.*]] = icmp sge i8 [[T0]], [[X:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = xor i8 %y, -1
+  call void @use8(i8 %t0)
+  %r = icmp sge i8 %t0, %x
+  ret i1 %r
+}
+
+define <2 x i1> @n12_vec_nonsplat(<2 x i8> %x, <2 x i8> %y) {
+; CHECK-LABEL: @n12_vec_nonsplat(
+; CHECK-NEXT:    [[T0:%.*]] = xor <2 x i8> [[Y:%.*]], <i8 -1, i8 -2>
+; CHECK-NEXT:    call void @use2x8(<2 x i8> [[T0]])
+; CHECK-NEXT:    [[R:%.*]] = icmp uge <2 x i8> [[T0]], [[X:%.*]]
+; CHECK-NEXT:    ret <2 x i1> [[R]]
+;
+  %t0 = xor <2 x i8> %y, <i8 -1, i8 -2> ; must be -1.
+  call void @use2x8(<2 x i8> %t0)
+  %r = icmp uge <2 x i8> %t0, %x
+  ret <2 x i1> %r
+}