1 files changed, 78 insertions, 0 deletions
diff --git a/clang/test/CodeGen/builtin-align-array.c b/clang/test/CodeGen/builtin-align-array.c
new file mode 100644
index 00000000000..97235c33b7f
--- /dev/null
+++ b/clang/test/CodeGen/builtin-align-array.c
@@ -0,0 +1,78 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py
+/// Check that the alignment builtins handle array-to-pointer decay
+// RUN: %clang_cc1 -triple=x86_64-unknown-unknown -o - -emit-llvm %s | FileCheck %s
+
+extern int func(char *c);
+
+// CHECK-LABEL: define {{[^@]+}}@test_array() #0
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[BUF:%.*]] = alloca [1024 x i8], align 16
+// CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds [1024 x i8], [1024 x i8]* [[BUF]], i64 0, i64 44
+// CHECK-NEXT:    [[INTPTR:%.*]] = ptrtoint i8* [[ARRAYIDX]] to i64
+// CHECK-NEXT:    [[ALIGNED_INTPTR:%.*]] = and i64 [[INTPTR]], -16
+// CHECK-NEXT:    [[DIFF:%.*]] = sub i64 [[ALIGNED_INTPTR]], [[INTPTR]]
+// CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = getelementptr inbounds i8, i8* [[ARRAYIDX]], i64 [[DIFF]]
+// CHECK-NEXT:    [[PTRINT:%.*]] = ptrtoint i8* [[ALIGNED_RESULT]] to i64
+// CHECK-NEXT:    [[MASKEDPTR:%.*]] = and i64 [[PTRINT]], 15
+// CHECK-NEXT:    [[MASKCOND:%.*]] = icmp eq i64 [[MASKEDPTR]], 0
+// CHECK-NEXT:    call void @llvm.assume(i1 [[MASKCOND]])
+// CHECK-NEXT:    [[CALL:%.*]] = call i32 @func(i8* [[ALIGNED_RESULT]])
+// CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds [1024 x i8], [1024 x i8]* [[BUF]], i64 0, i64 22
+// CHECK-NEXT:    [[INTPTR2:%.*]] = ptrtoint i8* [[ARRAYIDX1]] to i64
+// CHECK-NEXT:    [[OVER_BOUNDARY:%.*]] = add i64 [[INTPTR2]], 31
+// CHECK-NEXT:    [[ALIGNED_INTPTR4:%.*]] = and i64 [[OVER_BOUNDARY]], -32
+// CHECK-NEXT:    [[DIFF5:%.*]] = sub i64 [[ALIGNED_INTPTR4]], [[INTPTR2]]
+// CHECK-NEXT:    [[ALIGNED_RESULT6:%.*]] = getelementptr inbounds i8, i8* [[ARRAYIDX1]], i64 [[DIFF5]]
+// CHECK-NEXT:    [[PTRINT7:%.*]] = ptrtoint i8* [[ALIGNED_RESULT6]] to i64
+// CHECK-NEXT:    [[MASKEDPTR8:%.*]] = and i64 [[PTRINT7]], 31
+// CHECK-NEXT:    [[MASKCOND9:%.*]] = icmp eq i64 [[MASKEDPTR8]], 0
+// CHECK-NEXT:    call void @llvm.assume(i1 [[MASKCOND9]])
+// CHECK-NEXT:    [[CALL10:%.*]] = call i32 @func(i8* [[ALIGNED_RESULT6]])
+// CHECK-NEXT:    [[ARRAYIDX11:%.*]] = getelementptr inbounds [1024 x i8], [1024 x i8]* [[BUF]], i64 0, i64 16
+// CHECK-NEXT:    [[SRC_ADDR:%.*]] = ptrtoint i8* [[ARRAYIDX11]] to i64
+// CHECK-NEXT:    [[SET_BITS:%.*]] = and i64 [[SRC_ADDR]], 63
+// CHECK-NEXT:    [[IS_ALIGNED:%.*]] = icmp eq i64 [[SET_BITS]], 0
+// CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[IS_ALIGNED]] to i32
+// CHECK-NEXT:    ret i32 [[CONV]]
+//
+int test_array(void) {
+  char buf[1024];
+  func(__builtin_align_down(&buf[44], 16));
+  func(__builtin_align_up(&buf[22], 32));
+  return __builtin_is_aligned(&buf[16], 64);
+}
+
+// CHECK-LABEL: define {{[^@]+}}@test_array_should_not_mask() #0
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[BUF:%.*]] = alloca [1024 x i8], align 32
+// CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds [1024 x i8], [1024 x i8]* [[BUF]], i64 0, i64 64
+// CHECK-NEXT:    [[INTPTR:%.*]] = ptrtoint i8* [[ARRAYIDX]] to i64
+// CHECK-NEXT:    [[ALIGNED_INTPTR:%.*]] = and i64 [[INTPTR]], -16
+// CHECK-NEXT:    [[DIFF:%.*]] = sub i64 [[ALIGNED_INTPTR]], [[INTPTR]]
+// CHECK-NEXT:    [[ALIGNED_RESULT:%.*]] = getelementptr inbounds i8, i8* [[ARRAYIDX]], i64 [[DIFF]]
+// CHECK-NEXT:    [[PTRINT:%.*]] = ptrtoint i8* [[ALIGNED_RESULT]] to i64
+// CHECK-NEXT:    [[MASKEDPTR:%.*]] = and i64 [[PTRINT]], 15
+// CHECK-NEXT:    [[MASKCOND:%.*]] = icmp eq i64 [[MASKEDPTR]], 0
+// CHECK-NEXT:    call void @llvm.assume(i1 [[MASKCOND]])
+// CHECK-NEXT:    [[CALL:%.*]] = call i32 @func(i8* [[ALIGNED_RESULT]])
+// CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds [1024 x i8], [1024 x i8]* [[BUF]], i64 0, i64 32
+// CHECK-NEXT:    [[INTPTR2:%.*]] = ptrtoint i8* [[ARRAYIDX1]] to i64
+// CHECK-NEXT:    [[OVER_BOUNDARY:%.*]] = add i64 [[INTPTR2]], 31
+// CHECK-NEXT:    [[ALIGNED_INTPTR4:%.*]] = and i64 [[OVER_BOUNDARY]], -32
+// CHECK-NEXT:    [[DIFF5:%.*]] = sub i64 [[ALIGNED_INTPTR4]], [[INTPTR2]]
+// CHECK-NEXT:    [[ALIGNED_RESULT6:%.*]] = getelementptr inbounds i8, i8* [[ARRAYIDX1]], i64 [[DIFF5]]
+// CHECK-NEXT:    [[PTRINT7:%.*]] = ptrtoint i8* [[ALIGNED_RESULT6]] to i64
+// CHECK-NEXT:    [[MASKEDPTR8:%.*]] = and i64 [[PTRINT7]], 31
+// CHECK-NEXT:    [[MASKCOND9:%.*]] = icmp eq i64 [[MASKEDPTR8]], 0
+// CHECK-NEXT:    call void @llvm.assume(i1 [[MASKCOND9]])
+// CHECK-NEXT:    [[CALL10:%.*]] = call i32 @func(i8* [[ALIGNED_RESULT6]])
+// CHECK-NEXT:    ret i32 1
+//
+int test_array_should_not_mask(void) {
+  _Alignas(32) char buf[1024];
+  // TODO: The align_up and align_down calls should be folded to no-ops
+  func(__builtin_align_down(&buf[64], 16));
+  func(__builtin_align_up(&buf[32], 32));
+  // This expression can be constant-evaluated:
+  return __builtin_is_aligned(&buf[64], 32);
+}