From ac4dda805217f076e8dda009e7433dd278d7113e Mon Sep 17 00:00:00 2001
From: Roman Lebedev <lebedev.ri@gmail.com>
Date: Sat, 21 Sep 2019 22:27:18 +0000
Subject: [PATCH] [NFC][InstSimplify] Add exhaustive test coverage for
 simplifyUnsignedRangeCheck().

One case is not handled.

llvm-svn: 372489
---
 .../InstSimplify/unsigned-range-checks.ll          | 132 +++++++++++++++++++++
 1 file changed, 132 insertions(+)
 create mode 100644 llvm/test/Transforms/InstSimplify/unsigned-range-checks.ll

diff --git a/llvm/test/Transforms/InstSimplify/unsigned-range-checks.ll b/llvm/test/Transforms/InstSimplify/unsigned-range-checks.ll
new file mode 100644
index 0000000..d30fee9
--- /dev/null
+++ b/llvm/test/Transforms/InstSimplify/unsigned-range-checks.ll
@@ -0,0 +1,132 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt %s -instsimplify -S | FileCheck %s
+
+; Here we add unsigned two values, check that addition did not underflow AND
+; that the result is non-zero. This can be simplified just to a comparison
+; between the base and negated offset.
+
+; If we are checking that the result is not null or no underflow happened,
+; it is tautological (always-true).
+define i1 @t1(i8 %x, i8 %y) {
+; CHECK-LABEL: @t1(
+; CHECK-NEXT:    ret i1 true
+;
+  %not_null = icmp ne i8 %y, 0
+  %no_underflow = icmp ule i8 %y, %x
+  %r = or i1 %not_null, %no_underflow
+  ret i1 %r
+}
+define i1 @t2_commutative(i8 %x, i8 %y) {
+; CHECK-LABEL: @t2_commutative(
+; CHECK-NEXT:    ret i1 true
+;
+  %not_null = icmp ne i8 %y, 0
+  %no_underflow = icmp uge i8 %x, %y ; swapped
+  %r = or i1 %not_null, %no_underflow
+  ret i1 %r
+}
+
+define i1 @t3_commutative(i8 %x, i8 %y) {
+; CHECK-LABEL: @t3_commutative(
+; CHECK-NEXT:    ret i1 true
+;
+  %not_null = icmp ne i8 %y, 0
+  %no_underflow = icmp ule i8 %y, %x
+  %r = or i1 %no_underflow, %not_null ; swapped
+  ret i1 %r
+}
+define i1 @t4_commutative(i8 %x, i8 %y) {
+; CHECK-LABEL: @t4_commutative(
+; CHECK-NEXT:    ret i1 true
+;
+  %not_null = icmp ne i8 %y, 0
+  %no_underflow = icmp uge i8 %x, %y ; swapped
+  %r = or i1 %no_underflow, %not_null ; swapped
+  ret i1 %r
+}
+
+; If we are checking that the result is null and underflow happened,
+; it is tautological (always-false).
+define i1 @t5(i8 %x, i8 %y) {
+; CHECK-LABEL: @t5(
+; CHECK-NEXT:    ret i1 false
+;
+  %not_null = icmp eq i8 %y, 0
+  %no_underflow = icmp ugt i8 %y, %x
+  %r = and i1 %not_null, %no_underflow
+  ret i1 %r
+}
+define i1 @t6_commutative(i8 %x, i8 %y) {
+; CHECK-LABEL: @t6_commutative(
+; CHECK-NEXT:    ret i1 false
+;
+  %not_null = icmp eq i8 %y, 0
+  %no_underflow = icmp ult i8 %x, %y ; swapped
+  %r = and i1 %not_null, %no_underflow
+  ret i1 %r
+}
+
+; We only need to know that any of the 'add' operands is non-zero,
+; not necessarily the one used in the comparison.
+define i1 @t7(i8 %x, i8 %y) {
+; CHECK-LABEL: @t7(
+; CHECK-NEXT:    ret i1 true
+;
+  %cmp = icmp slt i8 %y, 0
+  %not_null = icmp ne i8 %y, 0
+  %no_underflow = icmp ule i8 %y, %x
+  %r = or i1 %not_null, %no_underflow
+  ret i1 %r
+}
+
+; If we check that no underflow happened and that the result is null,
+; we can just check for null.
+define i1 @t8(i8 %x, i8 %y) {
+; CHECK-LABEL: @t8(
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp eq i8 [[Y:%.*]], 0
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ule i8 [[Y]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %not_null = icmp eq i8 %y, 0
+  %no_underflow = icmp ule i8 %y, %x
+  %r = and i1 %not_null, %no_underflow
+  ret i1 %r
+}
+; Likewise, if we check that result is non-null or underflow happened,
+; we can just check for null.
+define i1 @t9(i8 %x, i8 %y) {
+; CHECK-LABEL: @t9(
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp ne i8 [[Y:%.*]], 0
+; CHECK-NEXT:    ret i1 [[NOT_NULL]]
+;
+  %not_null = icmp ne i8 %y, 0
+  %no_underflow = icmp ugt i8 %y, %x
+  %r = or i1 %not_null, %no_underflow
+  ret i1 %r
+}
+
+; If we check that no underflow happened or that the result is not null,
+; we can just check for lack of underflow.
+define i1 @t10(i8 %x, i8 %y) {
+; CHECK-LABEL: @t10(
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ule i8 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    ret i1 [[NO_UNDERFLOW]]
+;
+  %not_null = icmp eq i8 %y, 0
+  %no_underflow = icmp ule i8 %y, %x
+  %r = or i1 %not_null, %no_underflow
+  ret i1 %r
+}
+; Likewise, if we check that underflow happened and that the result is not null,
+; we can just check for lack of underflow.
+define i1 @t11(i8 %x, i8 %y) {
+; CHECK-LABEL: @t11(
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ugt i8 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    ret i1 [[NO_UNDERFLOW]]
+;
+  %not_null = icmp ne i8 %y, 0
+  %no_underflow = icmp ugt i8 %y, %x
+  %r = and i1 %not_null, %no_underflow
+  ret i1 %r
+}
-- 
2.7.4