[InstCombine] add tests for uaddsat using min; NFC

llvm-svn: 357005

Author: rotateright

llvm/test/Transforms/InstCombine/saturating-add-sub.ll

@@ -1248,3 +1248,89 @@ define <4 x i32> @uadd_sat_constant_vec_commute_undefs(<4 x i32> %x) {
   ret <4 x i32> %r
 }
 
+declare i32 @get_i32()
+declare <2 x i8> @get_v2i8()
+
+define i32 @unsigned_sat_variable_using_min_add(i32 %x) {
+; CHECK-LABEL: @unsigned_sat_variable_using_min_add(
+; CHECK-NEXT:    [[Y:%.*]] = call i32 @get_i32()
+; CHECK-NEXT:    [[NOTY:%.*]] = xor i32 [[Y]], -1
+; CHECK-NEXT:    [[C:%.*]] = icmp ugt i32 [[NOTY]], [[X:%.*]]
+; CHECK-NEXT:    [[S:%.*]] = select i1 [[C]], i32 [[X]], i32 [[NOTY]]
+; CHECK-NEXT:    [[R:%.*]] = add i32 [[S]], [[Y]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %y = call i32 @get_i32() ; thwart complexity-based canonicalization
+  %noty = xor i32 %y, -1
+  %c = icmp ult i32 %x, %noty
+  %s = select i1 %c, i32 %x, i32 %noty
+  %r = add i32 %s, %y
+  ret i32 %r
+}
+
+define i32 @unsigned_sat_variable_using_min_commute_add(i32 %x) {
+; CHECK-LABEL: @unsigned_sat_variable_using_min_commute_add(
+; CHECK-NEXT:    [[Y:%.*]] = call i32 @get_i32()
+; CHECK-NEXT:    [[NOTY:%.*]] = xor i32 [[Y]], -1
+; CHECK-NEXT:    [[C:%.*]] = icmp ugt i32 [[NOTY]], [[X:%.*]]
+; CHECK-NEXT:    [[S:%.*]] = select i1 [[C]], i32 [[X]], i32 [[NOTY]]
+; CHECK-NEXT:    [[R:%.*]] = add i32 [[Y]], [[S]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %y = call i32 @get_i32() ; thwart complexity-based canonicalization
+  %noty = xor i32 %y, -1
+  %c = icmp ult i32 %x, %noty
+  %s = select i1 %c, i32 %x, i32 %noty
+  %r = add i32 %y, %s
+  ret i32 %r
+}
+
+define <2 x i8> @unsigned_sat_variable_using_min_commute_select(<2 x i8> %x) {
+; CHECK-LABEL: @unsigned_sat_variable_using_min_commute_select(
+; CHECK-NEXT:    [[Y:%.*]] = call <2 x i8> @get_v2i8()
+; CHECK-NEXT:    [[NOTY:%.*]] = xor <2 x i8> [[Y]], <i8 -1, i8 -1>
+; CHECK-NEXT:    [[C:%.*]] = icmp ult <2 x i8> [[NOTY]], [[X:%.*]]
+; CHECK-NEXT:    [[S:%.*]] = select <2 x i1> [[C]], <2 x i8> [[NOTY]], <2 x i8> [[X]]
+; CHECK-NEXT:    [[R:%.*]] = add <2 x i8> [[S]], [[Y]]
+; CHECK-NEXT:    ret <2 x i8> [[R]]
+;
+  %y = call <2 x i8> @get_v2i8() ; thwart complexity-based canonicalization
+  %noty = xor <2 x i8> %y, <i8 -1, i8 -1>
+  %c = icmp ult <2 x i8> %noty, %x
+  %s = select <2 x i1> %c, <2 x i8> %noty, <2 x i8> %x
+  %r = add <2 x i8> %s, %y
+  ret <2 x i8> %r
+}
+
+define <2 x i8> @unsigned_sat_variable_using_min_commute_add_select(<2 x i8> %x) {
+; CHECK-LABEL: @unsigned_sat_variable_using_min_commute_add_select(
+; CHECK-NEXT:    [[Y:%.*]] = call <2 x i8> @get_v2i8()
+; CHECK-NEXT:    [[NOTY:%.*]] = xor <2 x i8> [[Y]], <i8 -1, i8 -1>
+; CHECK-NEXT:    [[C:%.*]] = icmp ult <2 x i8> [[NOTY]], [[X:%.*]]
+; CHECK-NEXT:    [[S:%.*]] = select <2 x i1> [[C]], <2 x i8> [[NOTY]], <2 x i8> [[X]]
+; CHECK-NEXT:    [[R:%.*]] = add <2 x i8> [[Y]], [[S]]
+; CHECK-NEXT:    ret <2 x i8> [[R]]
+;
+  %y = call <2 x i8> @get_v2i8() ; thwart complexity-based canonicalization
+  %noty = xor <2 x i8> %y, <i8 -1, i8 -1>
+  %c = icmp ult <2 x i8> %noty, %x
+  %s = select <2 x i1> %c, <2 x i8> %noty, <2 x i8> %x
+  %r = add <2 x i8> %y, %s
+  ret <2 x i8> %r
+}
+
+; If we have a constant operand, there's no commutativity variation.
+
+define i32 @unsigned_sat_constant_using_min(i32 %x) {
+; CHECK-LABEL: @unsigned_sat_constant_using_min(
+; CHECK-NEXT:    [[C:%.*]] = icmp ult i32 [[X:%.*]], 42
+; CHECK-NEXT:    [[S:%.*]] = select i1 [[C]], i32 [[X]], i32 42
+; CHECK-NEXT:    [[R:%.*]] = add nsw i32 [[S]], -43
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %c = icmp ult i32 %x, 42
+  %s = select i1 %c, i32 %x, i32 42
+  %r = add i32 %s, -43
+  ret i32 %r
+}
+