[clang] [CIR] Upstream pointer subtraction handling (PR #163306)

[Andy Kaylor via cfe-commits]

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+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --check-prefix=CIR --input-file=%t.cir %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-llvm %s -o %t-cir.ll
+// RUN: FileCheck --check-prefix=LLVM --input-file=%t-cir.ll %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm %s -o %t.ll
+// RUN: FileCheck --check-prefix=OGCG --input-file=%t.ll %s
+
+int addrcmp(const void* a, const void* b) {
+  // CIR-LABEL: addrcmp
+  // CIR: %[[R:.*]] = cir.ptr_diff
+  // CIR: cir.cast integral %[[R]] : !s64i -> !s32i
+
+  // LLVM-LABEL: define dso_local i32 @addrcmp(
+  // LLVM: %[[PTR_A:.*]] = ptrtoint ptr {{.*}} to i64
+  // LLVM: %[[PTR_B:.*]] = ptrtoint ptr {{.*}} to i64
+  // LLVM: %[[SUB:.*]] = sub i64 %[[PTR_A]], %[[PTR_B]]
+  // LLVM-NOT: sdiv
+  // LLVM: trunc i64 %[[SUB]] to i32
+
+  // OGCG-LABEL: define dso_local i32 @addrcmp(
+  // OGCG: %[[PTR_A:.*]] = ptrtoint ptr {{.*}} to i64
+  // OGCG: %[[PTR_B:.*]] = ptrtoint ptr {{.*}} to i64
+  // OGCG: %[[SUB:.*]] = sub i64 %[[PTR_A]], %[[PTR_B]]
+  // OGCG-NOT: sdiv
+  // OGCG: trunc i64 %[[SUB]] to i32
+  return *(const void**)a - *(const void**)b;
+}
+
+unsigned long long test_ptr_diff(int *a, int* b) {
+  // CIR-LABEL: test_ptr_diff
+  // CIR: %[[D:.*]] = cir.ptr_diff {{.*}} : !cir.ptr<!s32i> -> !s64i
+  // CIR: %[[U:.*]] = cir.cast integral %[[D]] : !s64i -> !u64i
+  // CIR: cir.return {{.*}} : !u64i
+
+  // LLVM-LABEL: define dso_local i64 @test_ptr_diff(
+  // LLVM: %[[IA:.*]] = ptrtoint ptr %{{.*}} to i64
+  // LLVM: %[[IB:.*]] = ptrtoint ptr %{{.*}} to i64
+  // LLVM: %[[SUB:.*]] = sub i64 %[[IA]], %[[IB]]
+  // LLVM: %[[Q:.*]] = sdiv exact i64 %[[SUB]], 4
+  // LLVM: store i64 %[[Q]], ptr %[[RETADDR:.*]], align
+  // LLVM: %[[RETLOAD:.*]] = load i64, ptr %[[RETADDR]], align
+  // LLVM: ret i64 %[[RETLOAD]]
+
+  // OGCG-LABEL: define dso_local i64 @test_ptr_diff(
+  // OGCG: %[[IA:.*]] = ptrtoint ptr %{{.*}} to i64
+  // OGCG: %[[IB:.*]] = ptrtoint ptr %{{.*}} to i64
+  // OGCG: %[[SUB:.*]] = sub i64 %[[IA]], %[[IB]]
+  // OGCG: %[[Q:.*]] = sdiv exact i64 %[[SUB]], 4
+  // OGCG: ret i64 %[[Q]]
+  return a - b;
+}
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andykaylor wrote:

This mark indicates that there is no line feed at the end of the file. We generally try to avoid that. The easiest way is to configure your editor to add it automatically when you save a file. Since this PR otherwise looks ready to go, it's fine to leave this until the next time the file is modified.

https://github.com/llvm/llvm-project/pull/163306