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..48f963f58e8 --- /dev/null +++ b/test/CodeGen/X86/force-align-stack-alloca.ll @@ -0,0 +1,63 @@ +; 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 -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 +; CHECK-NEXT: movl %esp, %ebp +; CHECK-NEXT: pushl +; CHECK-NEXT: subl $20, %esp +; 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 +; +; Finally we nede to restore %esp from %ebp, the alloca prevents us from +; restoring it directly. +; CHECK-NOT: popl +; CHECK: leal -4(%ebp), %esp +; CHECK-NEXT: popl +; CHECK-NEXT: popl +; 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