1 files changed, 107 insertions, 0 deletions
diff --git a/llvm/test/Transforms/InstCombine/unsigned-mul-lack-of-overflow-check-via-udiv-of-allones.ll b/llvm/test/Transforms/InstCombine/unsigned-mul-lack-of-overflow-check-via-udiv-of-allones.ll
new file mode 100644
index 00000000000..2865dfafd51
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/unsigned-mul-lack-of-overflow-check-via-udiv-of-allones.ll
@@ -0,0 +1,107 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt %s -instcombine -S | FileCheck %s
+
+; Fold
+;   (-1 u/ %x) u>= %y
+; to
+;   @llvm.umul.with.overflow(%x, %y) + extractvalue + not
+
+define i1 @t0_basic(i8 %x, i8 %y) {
+; CHECK-LABEL: @t0_basic(
+; CHECK-NEXT:    [[T0:%.*]] = udiv i8 -1, [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp uge i8 [[T0]], [[Y:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = udiv i8 -1, %x
+  %r = icmp uge i8 %t0, %y
+  ret i1 %r
+}
+
+define <2 x i1> @t1_vec(<2 x i8> %x, <2 x i8> %y) {
+; CHECK-LABEL: @t1_vec(
+; CHECK-NEXT:    [[T0:%.*]] = udiv <2 x i8> <i8 -1, i8 -1>, [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp uge <2 x i8> [[T0]], [[Y:%.*]]
+; CHECK-NEXT:    ret <2 x i1> [[R]]
+;
+  %t0 = udiv <2 x i8> <i8 -1, i8 -1>, %x
+  %r = icmp uge <2 x i8> %t0, %y
+  ret <2 x i1> %r
+}
+
+define <3 x i1> @t2_vec_undef(<3 x i8> %x, <3 x i8> %y) {
+; CHECK-LABEL: @t2_vec_undef(
+; CHECK-NEXT:    [[T0:%.*]] = udiv <3 x i8> <i8 -1, i8 undef, i8 -1>, [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp uge <3 x i8> [[T0]], [[Y:%.*]]
+; CHECK-NEXT:    ret <3 x i1> [[R]]
+;
+  %t0 = udiv <3 x i8> <i8 -1, i8 undef, i8 -1>, %x
+  %r = icmp uge <3 x i8> %t0, %y
+  ret <3 x i1> %r
+}
+
+declare i8 @gen8()
+
+define i1 @t3_commutative(i8 %x) {
+; CHECK-LABEL: @t3_commutative(
+; CHECK-NEXT:    [[T0:%.*]] = udiv i8 -1, [[X:%.*]]
+; CHECK-NEXT:    [[Y:%.*]] = call i8 @gen8()
+; CHECK-NEXT:    [[R:%.*]] = icmp ult i8 [[Y]], [[T0]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = udiv i8 -1, %x
+  %y = call i8 @gen8()
+  %r = icmp ult i8 %y, %t0 ; swapped
+  ret i1 %r
+}
+
+; Negative tests
+
+declare void @use8(i8)
+
+define i1 @n4_extrause(i8 %x, i8 %y) {
+; CHECK-LABEL: @n4_extrause(
+; CHECK-NEXT:    [[T0:%.*]] = udiv i8 -1, [[X:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[T0]])
+; CHECK-NEXT:    [[R:%.*]] = icmp uge i8 [[T0]], [[Y:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = udiv i8 -1, %x
+  call void @use8(i8 %t0)
+  %r = icmp uge i8 %t0, %y
+  ret i1 %r
+}
+
+define i1 @n5_not_negone(i8 %x, i8 %y) {
+; CHECK-LABEL: @n5_not_negone(
+; CHECK-NEXT:    [[T0:%.*]] = udiv i8 -2, [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp uge i8 [[T0]], [[Y:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = udiv i8 -2, %x ; not -1
+  %r = icmp uge i8 %t0, %y
+  ret i1 %r
+}
+
+define i1 @n6_wrong_pred0(i8 %x, i8 %y) {
+; CHECK-LABEL: @n6_wrong_pred0(
+; CHECK-NEXT:    [[T0:%.*]] = udiv i8 -1, [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp ule i8 [[T0]], [[Y:%.*]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = udiv i8 -1, %x
+  %r = icmp ule i8 %t0, %y
+  ret i1 %r
+}
+
+define i1 @n6_wrong_pred1(i8 %x) {
+; CHECK-LABEL: @n6_wrong_pred1(
+; CHECK-NEXT:    [[T0:%.*]] = udiv i8 -1, [[X:%.*]]
+; CHECK-NEXT:    [[Y:%.*]] = call i8 @gen8()
+; CHECK-NEXT:    [[R:%.*]] = icmp ugt i8 [[Y]], [[T0]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = udiv i8 -1, %x
+  %y = call i8 @gen8()
+  %r = icmp ugt i8 %y, %t0 ; swapped
+  ret i1 %r
+}