Add regression test for pointer return value specialization

- Add regression test which motivates removing the conditional check to
  only consider recursive functions on successive iterations when
  SpecializeLiteralConstant=false

Author: hazzlim

llvm/test/Transforms/FunctionSpecialization/function-specialization-track-ptr-return.ll

@@ -0,0 +1,147 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --include-generated-funcs --version 5
+; RUN: opt -passes="ipsccp<func-spec>" -force-specialization \
+; RUN:     -funcspec-max-iters=3 -S < %s | FileCheck %s
+
+; RUN: opt -passes="ipsccp<func-spec>" -force-specialization          \
+; RUN:     -funcspec-for-literal-constant=false -funcspec-max-iters=3 \
+; RUN:     -S < %s | FileCheck %s --check-prefix=NOLIT
+
+@global_true = constant i1 true
+@global_false = constant i1 false
+
+define i64 @main() {
+entry:
+  %binop1 = call ptr @select_binop(ptr @global_true)
+  %binop2 = call ptr @select_binop(ptr @global_false)
+
+  %c1 = call i64 @compute(ptr %binop1)
+  %c2 = call i64 @compute(ptr %binop2)
+  %add = add i64 %c1, %c2
+  ret i64 %add
+}
+
+define ptr @select_binop(ptr %flag) {
+  %flag.val = load i1, ptr %flag
+  %binop = select i1 %flag.val, ptr @plus, ptr @minus
+  ret ptr %binop
+}
+
+define internal i64 @compute(ptr %binop) {
+entry:
+  %res = call i64 %binop(i64 1, i64 1)
+  ret i64 %res
+}
+
+define internal i64 @plus(i64 %x) {
+entry:
+  %sum = add i64 %x, 1
+  ret i64 %sum
+}
+
+define internal i64 @minus(i64 %x) {
+entry:
+  %diff = sub i64 %x, 1
+  ret i64 %diff
+}
+; CHECK-LABEL: define i64 @main() {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[BINOP1:%.*]] = call ptr @select_binop.specialized.1(ptr @global_true)
+; CHECK-NEXT:    [[BINOP2:%.*]] = call ptr @select_binop.specialized.2(ptr @global_false)
+; CHECK-NEXT:    [[C1:%.*]] = call i64 @compute.specialized.3(ptr @plus)
+; CHECK-NEXT:    [[C2:%.*]] = call i64 @compute.specialized.4(ptr @minus)
+; CHECK-NEXT:    [[ADD:%.*]] = add i64 [[C1]], [[C2]]
+; CHECK-NEXT:    ret i64 [[ADD]]
+;
+;
+; CHECK-LABEL: define ptr @select_binop(
+; CHECK-SAME: ptr [[FLAG:%.*]]) {
+; CHECK-NEXT:    [[FLAG_VAL:%.*]] = load i1, ptr [[FLAG]], align 1
+; CHECK-NEXT:    [[BINOP:%.*]] = select i1 [[FLAG_VAL]], ptr @plus, ptr @minus
+; CHECK-NEXT:    ret ptr [[BINOP]]
+;
+;
+; CHECK-LABEL: define internal i64 @plus(
+; CHECK-SAME: i64 [[X:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[SUM:%.*]] = add i64 [[X]], 1
+; CHECK-NEXT:    ret i64 [[SUM]]
+;
+;
+; CHECK-LABEL: define internal i64 @minus(
+; CHECK-SAME: i64 [[X:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[DIFF:%.*]] = sub i64 [[X]], 1
+; CHECK-NEXT:    ret i64 [[DIFF]]
+;
+;
+; CHECK-LABEL: define internal ptr @select_binop.specialized.1(
+; CHECK-SAME: ptr [[FLAG:%.*]]) {
+; CHECK-NEXT:    ret ptr poison
+;
+;
+; CHECK-LABEL: define internal ptr @select_binop.specialized.2(
+; CHECK-SAME: ptr [[FLAG:%.*]]) {
+; CHECK-NEXT:    ret ptr poison
+;
+;
+; CHECK-LABEL: define internal i64 @compute.specialized.3(
+; CHECK-SAME: ptr [[BINOP:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[RES:%.*]] = call i64 @plus(i64 1, i64 1)
+; CHECK-NEXT:    ret i64 [[RES]]
+;
+;
+; CHECK-LABEL: define internal i64 @compute.specialized.4(
+; CHECK-SAME: ptr [[BINOP:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[RES:%.*]] = call i64 @minus(i64 1, i64 1)
+; CHECK-NEXT:    ret i64 [[RES]]
+;
+;
+; NOLIT-LABEL: define i64 @main() {
+; NOLIT-NEXT:  [[ENTRY:.*:]]
+; NOLIT-NEXT:    [[BINOP1:%.*]] = call ptr @select_binop.specialized.1(ptr @global_true)
+; NOLIT-NEXT:    [[BINOP2:%.*]] = call ptr @select_binop.specialized.2(ptr @global_false)
+; NOLIT-NEXT:    [[C1:%.*]] = call i64 @compute(ptr @plus)
+; NOLIT-NEXT:    [[C2:%.*]] = call i64 @compute(ptr @minus)
+; NOLIT-NEXT:    [[ADD:%.*]] = add i64 [[C1]], [[C2]]
+; NOLIT-NEXT:    ret i64 [[ADD]]
+;
+;
+; NOLIT-LABEL: define ptr @select_binop(
+; NOLIT-SAME: ptr [[FLAG:%.*]]) {
+; NOLIT-NEXT:    [[FLAG_VAL:%.*]] = load i1, ptr [[FLAG]], align 1
+; NOLIT-NEXT:    [[BINOP:%.*]] = select i1 [[FLAG_VAL]], ptr @plus, ptr @minus
+; NOLIT-NEXT:    ret ptr [[BINOP]]
+;
+;
+; NOLIT-LABEL: define internal i64 @compute(
+; NOLIT-SAME: ptr [[BINOP:%.*]]) {
+; NOLIT-NEXT:  [[ENTRY:.*:]]
+; NOLIT-NEXT:    [[RES:%.*]] = call i64 [[BINOP]](i64 1, i64 1)
+; NOLIT-NEXT:    ret i64 [[RES]]
+;
+;
+; NOLIT-LABEL: define internal i64 @plus(
+; NOLIT-SAME: i64 [[X:%.*]]) {
+; NOLIT-NEXT:  [[ENTRY:.*:]]
+; NOLIT-NEXT:    [[SUM:%.*]] = add i64 [[X]], 1
+; NOLIT-NEXT:    ret i64 [[SUM]]
+;
+;
+; NOLIT-LABEL: define internal i64 @minus(
+; NOLIT-SAME: i64 [[X:%.*]]) {
+; NOLIT-NEXT:  [[ENTRY:.*:]]
+; NOLIT-NEXT:    [[DIFF:%.*]] = sub i64 [[X]], 1
+; NOLIT-NEXT:    ret i64 [[DIFF]]
+;
+;
+; NOLIT-LABEL: define internal ptr @select_binop.specialized.1(
+; NOLIT-SAME: ptr [[FLAG:%.*]]) {
+; NOLIT-NEXT:    ret ptr poison
+;
+;
+; NOLIT-LABEL: define internal ptr @select_binop.specialized.2(
+; NOLIT-SAME: ptr [[FLAG:%.*]]) {
+; NOLIT-NEXT:    ret ptr poison
+;