[Tests] Add a test showing how we handle overaligned allocas w/ no-realign-stack

(At the moment, we ignore the alignment requirement.)

llvm-svn: 366393

diff --git a/llvm/test/CodeGen/X86/alloca-overaligned.ll b/llvm/test/CodeGen/X86/alloca-overaligned.ll
new file mode 100644 (file)
index 0000000..8ac50d8
--- /dev/null
+++ b/llvm/test/CodeGen/X86/alloca-overaligned.ll
@@ -0,0 +1,55 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-pc-linux -mcpu=skylake | FileCheck %s
+
+declare void @capture(i64*)
+
+define void @test_natural() "no-realign-stack" {
+; CHECK-LABEL: test_natural:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    pushq %rax
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    movq %rsp, %rdi
+; CHECK-NEXT:    callq capture
+; CHECK-NEXT:    popq %rax
+; CHECK-NEXT:    .cfi_def_cfa_offset 8
+; CHECK-NEXT:    retq
+  %a = alloca i64
+  call void @capture(i64* %a)
+  ret void
+}
+
+define void @test_realign() {
+; CHECK-LABEL: test_realign:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    pushq %rbp
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    .cfi_offset %rbp, -16
+; CHECK-NEXT:    movq %rsp, %rbp
+; CHECK-NEXT:    .cfi_def_cfa_register %rbp
+; CHECK-NEXT:    andq $-64, %rsp
+; CHECK-NEXT:    subq $64, %rsp
+; CHECK-NEXT:    movq %rsp, %rdi
+; CHECK-NEXT:    callq capture
+; CHECK-NEXT:    movq %rbp, %rsp
+; CHECK-NEXT:    popq %rbp
+; CHECK-NEXT:    .cfi_def_cfa %rsp, 8
+; CHECK-NEXT:    retq
+  %a = alloca i64, align 64
+  call void @capture(i64* %a)
+  ret void
+}
+
+define void @test_norealign() "no-realign-stack" {
+; CHECK-LABEL: test_norealign:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    pushq %rax
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    movq %rsp, %rdi
+; CHECK-NEXT:    callq capture
+; CHECK-NEXT:    popq %rax
+; CHECK-NEXT:    .cfi_def_cfa_offset 8
+; CHECK-NEXT:    retq
+  %a = alloca i64, align 64
+  call void @capture(i64* %a)
+  ret void
+}