From 9f7075de5c6200f4efda736220ca7716738a5e0e Mon Sep 17 00:00:00 2001
From: Philip Reames <listmail@philipreames.com>
Date: Thu, 17 Feb 2022 12:00:44 -0800
Subject: [PATCH] {instsimplify] Precommit some tests for provable inequal
 pointers derived from allocas

---
 .../Transforms/InstSimplify/cmp-alloca-offsets.ll  | 202 +++++++++++++++++++++
 1 file changed, 202 insertions(+)
 create mode 100644 llvm/test/Transforms/InstSimplify/cmp-alloca-offsets.ll

diff --git a/llvm/test/Transforms/InstSimplify/cmp-alloca-offsets.ll b/llvm/test/Transforms/InstSimplify/cmp-alloca-offsets.ll
new file mode 100644
index 0000000..b59fee4
--- /dev/null
+++ b/llvm/test/Transforms/InstSimplify/cmp-alloca-offsets.ll
@@ -0,0 +1,202 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes=instsimplify -S | FileCheck %s
+target datalayout = "p:32:32-p1:64:64"
+
+; This is a collection of tests checking whether we can prove pointers
+; derived from two allocas as inequal *via offset checks*.  Note that
+; instcombine has alternate approaches (one cmp rule, and compare
+; bases of common offset) that also handles these, but with different
+; logic.
+
+; %a follows %b, derived equal
+define i1 @adjacent_alloca() {
+; CHECK-LABEL: @adjacent_alloca(
+; CHECK-NEXT:    [[A:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[B:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[B_OFF:%.*]] = getelementptr i8, i8* [[B]], i64 4
+; CHECK-NEXT:    [[RES:%.*]] = icmp ne i8* [[A]], [[B_OFF]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+  %a = alloca i8, i32 4
+  %b = alloca i8, i32 4
+  %a.off = getelementptr i8, i8* %a, i64 0
+  %b.off = getelementptr i8, i8* %b, i64 4
+  %res = icmp ne i8* %a.off, %b.off
+  ret i1 %res
+}
+
+; %b follows %a, derived equal
+define i1 @adjacent_alloca2() {
+; CHECK-LABEL: @adjacent_alloca2(
+; CHECK-NEXT:    [[A:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[B:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[A_OFF:%.*]] = getelementptr i8, i8* [[A]], i64 4
+; CHECK-NEXT:    [[RES:%.*]] = icmp ne i8* [[A_OFF]], [[B]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+  %a = alloca i8, i32 4
+  %b = alloca i8, i32 4
+  %a.off = getelementptr i8, i8* %a, i64 4
+  %b.off = getelementptr i8, i8* %b, i64 0
+  %res = icmp ne i8* %a.off, %b.off
+  ret i1 %res
+}
+
+; FIXME: Can't be equal
+define i1 @positive_non_equal_end() {
+; CHECK-LABEL: @positive_non_equal_end(
+; CHECK-NEXT:    [[A:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[B:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[A_OFF:%.*]] = getelementptr i8, i8* [[A]], i64 4
+; CHECK-NEXT:    [[B_OFF:%.*]] = getelementptr i8, i8* [[B]], i64 4
+; CHECK-NEXT:    [[RES:%.*]] = icmp ne i8* [[A_OFF]], [[B_OFF]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+  %a = alloca i8, i32 4
+  %b = alloca i8, i32 4
+  %a.off = getelementptr i8, i8* %a, i64 4
+  %b.off = getelementptr i8, i8* %b, i64 4
+  %res = icmp ne i8* %a.off, %b.off
+  ret i1 %res
+}
+
+; %b follows %a, derived equal
+define i1 @positive_equal_past_end() {
+; CHECK-LABEL: @positive_equal_past_end(
+; CHECK-NEXT:    [[A:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[B:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[A_OFF:%.*]] = getelementptr i8, i8* [[A]], i64 8
+; CHECK-NEXT:    [[B_OFF:%.*]] = getelementptr i8, i8* [[B]], i64 12
+; CHECK-NEXT:    [[RES:%.*]] = icmp ne i8* [[A_OFF]], [[B_OFF]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+  %a = alloca i8, i32 4
+  %b = alloca i8, i32 4
+  %a.off = getelementptr i8, i8* %a, i64 8
+  %b.off = getelementptr i8, i8* %b, i64 12
+  %res = icmp ne i8* %a.off, %b.off
+  ret i1 %res
+}
+
+define i1 @positive_non_equal() {
+; CHECK-LABEL: @positive_non_equal(
+; CHECK-NEXT:    ret i1 true
+;
+  %a = alloca i8, i32 4
+  %b = alloca i8, i32 4
+  %a.off = getelementptr i8, i8* %a, i64 3
+  %b.off = getelementptr i8, i8* %b, i64 3
+  %res = icmp ne i8* %a.off, %b.off
+  ret i1 %res
+}
+
+; %a follows %b, derived equal
+define i1 @one_neg_equal1() {
+; CHECK-LABEL: @one_neg_equal1(
+; CHECK-NEXT:    [[A:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[B:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[A_OFF:%.*]] = getelementptr i8, i8* [[A]], i64 -1
+; CHECK-NEXT:    [[B_OFF:%.*]] = getelementptr i8, i8* [[B]], i64 3
+; CHECK-NEXT:    [[RES:%.*]] = icmp ne i8* [[A_OFF]], [[B_OFF]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+  %a = alloca i8, i32 4
+  %b = alloca i8, i32 4
+  %a.off = getelementptr i8, i8* %a, i64 -1
+  %b.off = getelementptr i8, i8* %b, i64 3
+  %res = icmp ne i8* %a.off, %b.off
+  ret i1 %res
+}
+
+; %b follows %a, derived equal
+define i1 @one_neg_equal2() {
+; CHECK-LABEL: @one_neg_equal2(
+; CHECK-NEXT:    [[A:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[B:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[A_OFF:%.*]] = getelementptr i8, i8* [[A]], i64 3
+; CHECK-NEXT:    [[B_OFF:%.*]] = getelementptr i8, i8* [[B]], i64 -1
+; CHECK-NEXT:    [[RES:%.*]] = icmp ne i8* [[A_OFF]], [[B_OFF]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+  %a = alloca i8, i32 4
+  %b = alloca i8, i32 4
+  %a.off = getelementptr i8, i8* %a, i64 3
+  %b.off = getelementptr i8, i8* %b, i64 -1
+  %res = icmp ne i8* %a.off, %b.off
+  ret i1 %res
+}
+
+; %b follows %a, derived equal
+define i1 @both_neg_equal() {
+; CHECK-LABEL: @both_neg_equal(
+; CHECK-NEXT:    [[A:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[B:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[A_OFF:%.*]] = getelementptr i8, i8* [[A]], i64 -4
+; CHECK-NEXT:    [[B_OFF:%.*]] = getelementptr i8, i8* [[B]], i64 -8
+; CHECK-NEXT:    [[RES:%.*]] = icmp ne i8* [[A_OFF]], [[B_OFF]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+  %a = alloca i8, i32 4
+  %b = alloca i8, i32 4
+  %a.off = getelementptr i8, i8* %a, i64 -4
+  %b.off = getelementptr i8, i8* %b, i64 -8
+  %res = icmp ne i8* %a.off, %b.off
+  ret i1 %res
+}
+
+; FIXME: Can't be equal
+define i1 @mixed_offsets1() {
+; CHECK-LABEL: @mixed_offsets1(
+; CHECK-NEXT:    [[A:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[B:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[A_OFF:%.*]] = getelementptr i8, i8* [[A]], i64 -1
+; CHECK-NEXT:    [[B_OFF:%.*]] = getelementptr i8, i8* [[B]], i64 2
+; CHECK-NEXT:    [[RES:%.*]] = icmp ne i8* [[A_OFF]], [[B_OFF]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+  %a = alloca i8, i32 4
+  %b = alloca i8, i32 4
+  %a.off = getelementptr i8, i8* %a, i64 -1
+  %b.off = getelementptr i8, i8* %b, i64 2
+  %res = icmp ne i8* %a.off, %b.off
+  ret i1 %res
+}
+
+; FIXME: Can't be equal
+define i1 @mixed_offsets2() {
+; CHECK-LABEL: @mixed_offsets2(
+; CHECK-NEXT:    [[A:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[B:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[A_OFF:%.*]] = getelementptr i8, i8* [[A]], i64 1
+; CHECK-NEXT:    [[B_OFF:%.*]] = getelementptr i8, i8* [[B]], i64 -2
+; CHECK-NEXT:    [[RES:%.*]] = icmp ne i8* [[A_OFF]], [[B_OFF]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+  %a = alloca i8, i32 4
+  %b = alloca i8, i32 4
+  %a.off = getelementptr i8, i8* %a, i64 1
+  %b.off = getelementptr i8, i8* %b, i64 -2
+  %res = icmp ne i8* %a.off, %b.off
+  ret i1 %res
+}
+
+; FIXME: Can't be equal
+define i1 @negative_in_other() {
+; CHECK-LABEL: @negative_in_other(
+; CHECK-NEXT:    [[A:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[B:%.*]] = alloca i8, i32 4, align 1
+; CHECK-NEXT:    [[A_OFF:%.*]] = getelementptr i8, i8* [[A]], i64 -3
+; CHECK-NEXT:    [[B_OFF:%.*]] = getelementptr i8, i8* [[B]], i64 -2
+; CHECK-NEXT:    [[RES:%.*]] = icmp ne i8* [[A_OFF]], [[B_OFF]]
+; CHECK-NEXT:    ret i1 [[RES]]
+;
+  %a = alloca i8, i32 4
+  %b = alloca i8, i32 4
+  %a.off = getelementptr i8, i8* %a, i64 -3
+  %b.off = getelementptr i8, i8* %b, i64 -2
+  %res = icmp ne i8* %a.off, %b.off
+  ret i1 %res
+}
+
+
+attributes #0 = { null_pointer_is_valid }
-- 
2.7.4