[llvm] [SeperateConstOffsetFromGEP] Pre-commit tests for or disjoint handling (PR #76972)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Krzysztof Drewniak (krzysz00)

<details>
<summary>Changes</summary>

1. Adds tests for the existing interpretation of `or` as `add` in SeperateConstOffsetFromGEP.
2. Pre-commits a test for `or disjoint`.

---
Full diff: https://github.com/llvm/llvm-project/pull/76972.diff


1 Files Affected:

- (added) llvm/test/Transforms/SeparateConstOffsetFromGEP/split-gep-or-as-add.ll (+61) 


``````````diff
diff --git a/llvm/test/Transforms/SeparateConstOffsetFromGEP/split-gep-or-as-add.ll b/llvm/test/Transforms/SeparateConstOffsetFromGEP/split-gep-or-as-add.ll
new file mode 100644
index 00000000000000..45154f5a68f92c
--- /dev/null
+++ b/llvm/test/Transforms/SeparateConstOffsetFromGEP/split-gep-or-as-add.ll
@@ -0,0 +1,61 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt -S -passes="separate-const-offset-from-gep<lower-gep>" < %s | FileCheck %s
+
+;; Check that or operations, either with operands with no bits in common or that
+;; are disjoint are lowered into constant GEPs. Note that because this is a
+;; target-independent test, the GEP seperator will lower the seperated-off constant
+;; part to ptrtoint-based arithmetic.
+
+define void @testOrDoesntSplit(ptr %p) {
+; CHECK-LABEL: define void @testOrDoesntSplit(
+; CHECK-SAME: ptr [[P:%.*]]) {
+; CHECK-NEXT:    [[VAR:%.*]] = tail call i64 @foo()
+; CHECK-NEXT:    [[OFF:%.*]] = or i64 [[VAR]], 10
+; CHECK-NEXT:    [[Q:%.*]] = getelementptr i8, ptr [[P]], i64 [[OFF]]
+; CHECK-NEXT:    store i8 0, ptr [[Q]], align 1
+; CHECK-NEXT:    ret void
+;
+  %var = tail call i64 @foo()
+  %off = or i64 %var, 10
+  %q = getelementptr i8, ptr %p, i64 %off
+  store i8 0, ptr %q
+  ret void
+}
+
+define void @testNoBitsInCommonOrSplits(ptr %p) {
+; CHECK-LABEL: define void @testNoBitsInCommonOrSplits(
+; CHECK-SAME: ptr [[P:%.*]]) {
+; CHECK-NEXT:    [[VAR:%.*]] = tail call i64 @foo()
+; CHECK-NEXT:    [[VAR_HIGH:%.*]] = and i64 [[VAR]], -16
+; CHECK-NEXT:    [[TMP1:%.*]] = ptrtoint ptr [[P]] to i64
+; CHECK-NEXT:    [[TMP2:%.*]] = add i64 [[TMP1]], [[VAR_HIGH]]
+; CHECK-NEXT:    [[TMP3:%.*]] = add i64 [[TMP2]], 10
+; CHECK-NEXT:    [[TMP4:%.*]] = inttoptr i64 [[TMP3]] to ptr
+; CHECK-NEXT:    store i8 0, ptr [[TMP4]], align 1
+; CHECK-NEXT:    ret void
+;
+  %var = tail call i64 @foo()
+  %var.high = and i64 %var, -16
+  %off = or i64 %var.high, 10
+  %q = getelementptr i8, ptr %p, i64 %off
+  store i8 0, ptr %q
+  ret void
+}
+
+define void @testDisjointOrSplits(ptr %p) {
+; CHECK-LABEL: define void @testDisjointOrSplits(
+; CHECK-SAME: ptr [[P:%.*]]) {
+; CHECK-NEXT:    [[VAR:%.*]] = tail call i64 @foo()
+; CHECK-NEXT:    [[OFF:%.*]] = or disjoint i64 [[VAR]], 10
+; CHECK-NEXT:    [[Q:%.*]] = getelementptr i8, ptr [[P]], i64 [[OFF]]
+; CHECK-NEXT:    store i8 0, ptr [[Q]], align 1
+; CHECK-NEXT:    ret void
+;
+  %var = tail call i64 @foo()
+  %off = or disjoint i64 %var, 10
+  %q = getelementptr i8, ptr %p, i64 %off
+  store i8 0, ptr %q
+  ret void
+}
+
+declare i64 @foo()

``````````

</details>


https://github.com/llvm/llvm-project/pull/76972