[NFC][InstCombine][InstSimplify] Add test for "add-of-negative is non-zero and no...

https://rise4fun.com/Alive/ska
https://rise4fun.com/Alive/9iX

https://bugs.llvm.org/show_bug.cgi?id=43259

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@371736 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/Transforms/InstCombine/result-of-add-of-negative-is-non-zero-and-no-underflow.ll b/test/Transforms/InstCombine/result-of-add-of-negative-is-non-zero-and-no-underflow.ll
new file mode 100644 (file)
index 0000000..1a376c4
--- /dev/null
+++ b/test/Transforms/InstCombine/result-of-add-of-negative-is-non-zero-and-no-underflow.ll
@@ -0,0 +1,235 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt %s -instcombine -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.
+
+declare void @use8(i8)
+
+declare void @use1(i1)
+declare void @llvm.assume(i1)
+
+; Here we don't know that at least one of the values being added is non-zero
+define i1 @t0_bad(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t0_bad(
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE:%.*]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]]
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %adjusted = add i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %not_null = icmp ne i8 %adjusted, 0
+  %no_underflow = icmp ult i8 %adjusted, %base
+  %r = and i1 %not_null, %no_underflow
+  ret i1 %r
+}
+
+; Ok, base is non-zero.
+define i1 @t1(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t1(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0
+; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]]
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %cmp = icmp slt i8 %base, 0
+  call void @llvm.assume(i1 %cmp)
+
+  %adjusted = add i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %not_null = icmp ne i8 %adjusted, 0
+  %no_underflow = icmp ult i8 %adjusted, %base
+  %r = and i1 %not_null, %no_underflow
+  ret i1 %r
+}
+
+; Ok, offset is non-zero.
+define i1 @t2(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t2(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[OFFSET:%.*]], 0
+; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE:%.*]], [[OFFSET]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]]
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %cmp = icmp slt i8 %offset, 0
+  call void @llvm.assume(i1 %cmp)
+
+  %adjusted = add i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %not_null = icmp ne i8 %adjusted, 0
+  %no_underflow = icmp ult i8 %adjusted, %base
+  %r = and i1 %not_null, %no_underflow
+  ret i1 %r
+}
+
+; We need to produce extra instruction, so one of icmp's must go away.
+define i1 @t3_oneuse0(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t3_oneuse0(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0
+; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    call void @use1(i1 [[NOT_NULL]])
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]]
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %cmp = icmp slt i8 %base, 0
+  call void @llvm.assume(i1 %cmp)
+
+  %adjusted = add i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %not_null = icmp ne i8 %adjusted, 0
+  call void @use1(i1 %not_null)
+  %no_underflow = icmp ult i8 %adjusted, %base
+  %r = and i1 %not_null, %no_underflow
+  ret i1 %r
+}
+define i1 @t4_oneuse1(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t4_oneuse1(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0
+; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]]
+; CHECK-NEXT:    call void @use1(i1 [[NO_UNDERFLOW]])
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %cmp = icmp slt i8 %base, 0
+  call void @llvm.assume(i1 %cmp)
+
+  %adjusted = add i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %not_null = icmp ne i8 %adjusted, 0
+  %no_underflow = icmp ult i8 %adjusted, %base
+  call void @use1(i1 %no_underflow)
+  %r = and i1 %not_null, %no_underflow
+  ret i1 %r
+}
+define i1 @t5_oneuse2_bad(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t5_oneuse2_bad(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0
+; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    call void @use1(i1 [[NOT_NULL]])
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]]
+; CHECK-NEXT:    call void @use1(i1 [[NO_UNDERFLOW]])
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %cmp = icmp slt i8 %base, 0
+  call void @llvm.assume(i1 %cmp)
+
+  %adjusted = add i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %not_null = icmp ne i8 %adjusted, 0
+  call void @use1(i1 %not_null)
+  %no_underflow = icmp ult i8 %adjusted, %base
+  call void @use1(i1 %no_underflow)
+  %r = and i1 %not_null, %no_underflow
+  ret i1 %r
+}
+
+define i1 @t6_commutativity0(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t6_commutativity0(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0
+; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]]
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NO_UNDERFLOW]], [[NOT_NULL]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %cmp = icmp slt i8 %base, 0
+  call void @llvm.assume(i1 %cmp)
+
+  %adjusted = add i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %not_null = icmp ne i8 %adjusted, 0
+  %no_underflow = icmp ult i8 %adjusted, %base
+  %r = and i1 %no_underflow, %not_null ; swapped
+  ret i1 %r
+}
+define i1 @t7_commutativity1(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t7_commutativity1(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0
+; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ule i8 [[ADJUSTED]], [[BASE]]
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %cmp = icmp slt i8 %base, 0
+  call void @llvm.assume(i1 %cmp)
+
+  %adjusted = add i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %not_null = icmp ne i8 %adjusted, 0
+  %no_underflow = icmp uge i8 %base, %adjusted ; swapped
+  %r = and i1 %not_null, %no_underflow
+  ret i1 %r
+}
+define i1 @t7_commutativity3(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t7_commutativity3(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0
+; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ule i8 [[ADJUSTED]], [[BASE]]
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NO_UNDERFLOW]], [[NOT_NULL]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %cmp = icmp slt i8 %base, 0
+  call void @llvm.assume(i1 %cmp)
+
+  %adjusted = add i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %not_null = icmp ne i8 %adjusted, 0
+  %no_underflow = icmp uge i8 %base, %adjusted ; swapped
+  %r = and i1 %no_underflow, %not_null ; swapped
+  ret i1 %r
+}
+
+; We could have the opposite question, did we get null or overflow happened?
+define i1 @t8(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t8(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0
+; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp eq i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp uge i8 [[ADJUSTED]], [[BASE]]
+; CHECK-NEXT:    [[R:%.*]] = or i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %cmp = icmp slt i8 %base, 0
+  call void @llvm.assume(i1 %cmp)
+
+  %adjusted = add i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %not_null = icmp eq i8 %adjusted, 0
+  %no_underflow = icmp uge i8 %adjusted, %base
+  %r = or i1 %not_null, %no_underflow
+  ret i1 %r
+}

diff --git a/test/Transforms/InstSimplify/result-of-add-of-negative-is-non-zero-and-no-underflow.ll b/test/Transforms/InstSimplify/result-of-add-of-negative-is-non-zero-and-no-underflow.ll
new file mode 100644 (file)
index 0000000..58a56c4
--- /dev/null
+++ b/test/Transforms/InstSimplify/result-of-add-of-negative-is-non-zero-and-no-underflow.ll
@@ -0,0 +1,101 @@
+; 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.
+
+declare void @use8(i8)
+
+declare void @use1(i1)
+declare void @llvm.assume(i1)
+
+; If we are checking that the result is not null or no underflow happened,
+; it is tautological (always-true).
+define i1 @t1(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t1(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0
+; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]]
+; CHECK-NEXT:    [[R:%.*]] = or i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %cmp = icmp slt i8 %base, 0
+  call void @llvm.assume(i1 %cmp)
+
+  %adjusted = add i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %not_null = icmp ne i8 %adjusted, 0
+  %no_underflow = icmp ult i8 %adjusted, %base
+  %r = or i1 %not_null, %no_underflow
+  ret i1 %r
+}
+define i1 @t2_commutative(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t2_commutative(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0
+; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ugt i8 [[BASE]], [[ADJUSTED]]
+; CHECK-NEXT:    [[R:%.*]] = or i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %cmp = icmp slt i8 %base, 0
+  call void @llvm.assume(i1 %cmp)
+
+  %adjusted = add i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %not_null = icmp ne i8 %adjusted, 0
+  %no_underflow = icmp ugt i8 %base, %adjusted
+  %r = or i1 %not_null, %no_underflow
+  ret i1 %r
+}
+
+; If we are checking that the result is null and underflow happened,
+; it is tautological (always-false).
+define i1 @t3(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t3(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0
+; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp eq i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp uge i8 [[ADJUSTED]], [[BASE]]
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %cmp = icmp slt i8 %base, 0
+  call void @llvm.assume(i1 %cmp)
+
+  %adjusted = add i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %not_null = icmp eq i8 %adjusted, 0
+  %no_underflow = icmp uge i8 %adjusted, %base
+  %r = and i1 %not_null, %no_underflow
+  ret i1 %r
+}
+define i1 @t4_commutative(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t4_commutative(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0
+; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp eq i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ule i8 [[BASE]], [[ADJUSTED]]
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %cmp = icmp slt i8 %base, 0
+  call void @llvm.assume(i1 %cmp)
+
+  %adjusted = add i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %not_null = icmp eq i8 %adjusted, 0
+  %no_underflow = icmp ule i8 %base, %adjusted
+  %r = and i1 %not_null, %no_underflow
+  ret i1 %r
+}