1 files changed, 70 insertions, 0 deletions
diff --git a/test/CodeGen/X86/force-align-stack-alloca.ll b/test/CodeGen/X86/force-align-stack-alloca.ll
new file mode 100644
index 00000000000..2ada194f891
--- /dev/null
+++ b/test/CodeGen/X86/force-align-stack-alloca.ll
@@ -0,0 +1,70 @@
+; This test is attempting to detect when we request forced re-alignment of the
+; stack to an alignment greater than would be available due to the ABI. We
+; arbitrarily force alignment up to 32-bytes for i386 hoping that this will
+; exceed any ABI provisions.
+;
+; RUN: llc < %s -mcpu=generic -force-align-stack -stack-alignment=32 | FileCheck %s
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32-S128"
+target triple = "i386-unknown-linux-gnu"
+
+define i32 @f(i8* %p) nounwind {
+entry:
+  %0 = load i8* %p
+  %conv = sext i8 %0 to i32
+  ret i32 %conv
+}
+
+define i64 @g(i32 %i) nounwind {
+; CHECK: g:
+; CHECK:      pushl  %ebp
+; CHECK-NEXT: movl   %esp, %ebp
+; CHECK-NEXT: pushl
+; CHECK-NEXT: pushl
+; CHECK-NEXT: andl   $-32, %esp
+; CHECK-NEXT: subl   $32, %esp
+;
+; Now setup the base pointer (%esi).
+; CHECK-NEXT: movl   %esp, %esi
+; CHECK-NOT:         {{[^ ,]*}}, %esp
+;
+; The next adjustment of the stack is due to the alloca.
+; CHECK:      movl   %{{...}}, %esp
+; CHECK-NOT:         {{[^ ,]*}}, %esp
+;
+; Next we set up the memset call, and then undo it.
+; CHECK:      subl   $32, %esp
+; CHECK-NOT:         {{[^ ,]*}}, %esp
+; CHECK:      calll  memset
+; CHECK-NEXT: addl   $32, %esp
+; CHECK-NOT:         {{[^ ,]*}}, %esp
+;
+; Next we set up the call to 'f'.
+; CHECK:      subl   $32, %esp
+; CHECK-NOT:         {{[^ ,]*}}, %esp
+; CHECK:      calll  f
+; CHECK-NEXT: addl   $32, %esp
+; CHECK-NOT:         {{[^ ,]*}}, %esp
+;
+; Restore %esp from %ebp (frame pointer) and subtract the size of
+; zone with callee-saved registers to pop them.
+; This is the state prior to stack realignment and the allocation of VLAs.
+; CHECK-NOT:  popl
+; CHECK:      leal   -8(%ebp), %esp
+; CHECK-NEXT: popl
+; CHECK-NEXT: popl
+; CHECK-NEXT: popl   %ebp
+; CHECK-NEXT: ret
+
+entry:
+  br label %if.then
+
+if.then:
+  %0 = alloca i8, i32 %i
+  call void @llvm.memset.p0i8.i32(i8* %0, i8 0, i32 %i, i32 1, i1 false)
+  %call = call i32 @f(i8* %0)
+  %conv = sext i32 %call to i64
+  ret i64 %conv
+}
+
+declare void @llvm.memset.p0i8.i32(i8*, i8, i32, i32, i1) nounwind