diff options
| author | Nadav Rotem <nrotem@apple.com> | 2012-12-21 23:48:49 +0000 |
|---|---|---|
| committer | Nadav Rotem <nrotem@apple.com> | 2012-12-21 23:48:49 +0000 |
| commit | d0696ef8c33b9b2504e89bc0aab2ea99a6c90756 (patch) | |
| tree | 6d9b823ad7696ccdc6ea1f61fb5aa78ce3afbb64 /test/CodeGen | |
| parent | dbf51ee4596791d8cf38538b80805b2c3a577836 (diff) | |
In some cases, due to scheduling constraints we copy the EFLAGS.
The only way to read the eflags is using push and pop. If we don't
adjust the stack then we run over the first frame index. This is
not something that we want to do, so we have to make sure that
our machine function does not copy the flags. If it does then
we have to emit the prolog that adjusts the stack.
rdar://12896831
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170961 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/CodeGen')
| -rw-r--r-- | test/CodeGen/X86/clobber-fi0.ll | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/test/CodeGen/X86/clobber-fi0.ll b/test/CodeGen/X86/clobber-fi0.ll new file mode 100644 index 0000000000..38a42dbf1a --- /dev/null +++ b/test/CodeGen/X86/clobber-fi0.ll @@ -0,0 +1,37 @@ +; RUN: llc < %s -mcpu=generic -mtriple=x86_64-linux | FileCheck %s + +target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128" +target triple = "x86_64-apple-macosx10.7.0" + +; In the code below we need to copy the EFLAGS because of scheduling constraints. +; When copying the EFLAGS we need to write to the stack with push/pop. This forces +; us to emit the prolog. + +; CHECK: main +; CHECK: subq{{.*}}rsp +; CHECK: ret +define i32 @main(i32 %arg, i8** %arg1) nounwind { +bb: + %tmp = alloca i32, align 4 ; [#uses=3 type=i32*] + %tmp2 = alloca i32, align 4 ; [#uses=3 type=i32*] + %tmp3 = alloca i32 ; [#uses=1 type=i32*] + store i32 1, i32* %tmp, align 4 + store i32 1, i32* %tmp2, align 4 + br label %bb4 + +bb4: ; preds = %bb4, %bb + %tmp6 = load i32* %tmp2, align 4 ; [#uses=1 type=i32] + %tmp7 = add i32 %tmp6, -1 ; [#uses=2 type=i32] + store i32 %tmp7, i32* %tmp2, align 4 + %tmp8 = icmp eq i32 %tmp7, 0 ; [#uses=1 type=i1] + %tmp9 = load i32* %tmp ; [#uses=1 type=i32] + %tmp10 = add i32 %tmp9, -1 ; [#uses=1 type=i32] + store i32 %tmp10, i32* %tmp3 + br i1 %tmp8, label %bb11, label %bb4 + +bb11: ; preds = %bb4 + %tmp12 = load i32* %tmp, align 4 ; [#uses=1 type=i32] + ret i32 %tmp12 +} + + |