Fix epilogue codegen to avoid leaving the stack pointer in an invalid
state. Previously Thumb2 would restore sp from fp like this:
mov sp, r7
sub, sp, #4
If an interrupt is taken after the 'mov' but before the 'sub', callee-saved
registers might be clobbered by the interrupt handler. Instead, try
restoring directly from sp:
add sp, #4
Or, if necessary (with VLA, etc.) use a scratch register to compute sp and
then restore it:
sub.w r4, r7, #8
mov sp, r7
rdar://8465407
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119977 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/Thumb2/2009-08-06-SpDecBug.ll b/test/CodeGen/Thumb2/2009-08-06-SpDecBug.ll
index f26c6d1..550b3ef 100644
--- a/test/CodeGen/Thumb2/2009-08-06-SpDecBug.ll
+++ b/test/CodeGen/Thumb2/2009-08-06-SpDecBug.ll
@@ -5,8 +5,13 @@
define hidden i32 @__gcov_execlp(i8* %path, i8* %arg, ...) nounwind {
entry:
; CHECK: __gcov_execlp:
-; CHECK: mov sp, r7
-; CHECK: sub sp, #4
+; CHECK: sub sp, #8
+; CHECK: push
+; CHECK: add r7, sp, #4
+; CHECK: subs r4, r7, #4
+; CHECK: mov sp, r4
+; CHECK-NOT: mov sp, r7
+; CHECK: add sp, #8
call void @__gcov_flush() nounwind
br i1 undef, label %bb5, label %bb