[InstCombine] add tests for binop with flags and select op; NFC

Author: rotateright

llvm/test/Transforms/InstCombine/select-2.ll

@@ -42,3 +42,69 @@ define float @t3(float %x, float %y) {
   %t3 = fadd fast float %t2, 1.0
   ret float %t3
 }
+
+define i8 @ashr_exact_poison_constant_fold(i1 %b, i8 %x) {
+; CHECK-LABEL: @ashr_exact_poison_constant_fold(
+; CHECK-NEXT:    [[X_OP:%.*]] = ashr i8 [[X:%.*]], 3
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[B:%.*]], i8 [[X_OP]], i8 5
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %s = select i1 %b, i8 %x, i8 42
+  %r = ashr exact i8 %s, 3
+  ret i8 %r
+}
+
+define i8 @ashr_exact(i1 %b, i8 %x) {
+; CHECK-LABEL: @ashr_exact(
+; CHECK-NEXT:    [[X_OP:%.*]] = ashr i8 [[X:%.*]], 3
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[B:%.*]], i8 [[X_OP]], i8 2
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %s = select i1 %b, i8 %x, i8 16
+  %r = ashr exact i8 %s, 3
+  ret i8 %r
+}
+
+define i8 @shl_nsw_nuw_poison_constant_fold(i1 %b, i8 %x) {
+; CHECK-LABEL: @shl_nsw_nuw_poison_constant_fold(
+; CHECK-NEXT:    [[X_OP:%.*]] = shl i8 16, [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[B:%.*]], i8 -128, i8 [[X_OP]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %s = select i1 %b, i8 3, i8 %x
+  %r = shl nsw nuw i8 16, %s
+  ret i8 %r
+}
+
+define i8 @shl_nsw_nuw(i1 %b, i8 %x) {
+; CHECK-LABEL: @shl_nsw_nuw(
+; CHECK-NEXT:    [[X_OP:%.*]] = shl i8 7, [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[B:%.*]], i8 56, i8 [[X_OP]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %s = select i1 %b, i8 3, i8 %x
+  %r = shl nsw nuw i8 7, %s
+  ret i8 %r
+}
+
+define i8 @add_nsw_poison_constant_fold(i1 %b, i8 %x) {
+; CHECK-LABEL: @add_nsw_poison_constant_fold(
+; CHECK-NEXT:    [[X_OP:%.*]] = add i8 [[X:%.*]], 64
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[B:%.*]], i8 [[X_OP]], i8 -127
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %s = select i1 %b, i8 %x, i8 65
+  %r = add nsw i8 %s, 64
+  ret i8 %r
+}
+
+define i8 @add_nsw(i1 %b, i8 %x) {
+; CHECK-LABEL: @add_nsw(
+; CHECK-NEXT:    [[X_OP:%.*]] = add i8 [[X:%.*]], 64
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[B:%.*]], i8 [[X_OP]], i8 71
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %s = select i1 %b, i8 %x, i8 7
+  %r = add nsw i8 %s, 64
+  ret i8 %r
+}