[X86,ARM] Retain split-stack prolog check for sibling calls

Summary:
If a routine with no stack frame makes a sibling call, we need to
preserve the stack space check even if the local stack frame is empty,
since the call target could be a "no-split" function (in which case
the linker needs to be able to fix up the prolog sequence in order to
switch to a larger stack).

This fixes PR37807.

Reviewers: cherry, javed.absar

Subscribers: srhines, llvm-commits

Differential Revision: https://reviews.llvm.org/D48444

llvm-svn: 335604

1 files changed, 18 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/ARM/segmented-stacks.ll b/llvm/test/CodeGen/ARM/segmented-stacks.ll
index 4fe84faa17f..971fdd96606 100644
--- a/llvm/test/CodeGen/ARM/segmented-stacks.ll
+++ b/llvm/test/CodeGen/ARM/segmented-stacks.ll
@@ -246,4 +246,22 @@ define void @test_nostack() #0 {
 ; ARM-android-NOT:   bl __morestack
 }
 
+; Test to make sure that a morestack call is generated if there is a
+; sibling call, even if the function in question has no stack frame
+; (PR37807).
+
+declare i32 @callee(i32)
+
+define i32 @test_sibling_call_empty_frame(i32 %x) #0 {
+  %call = tail call i32 @callee(i32 %x) #0
+  ret i32 %call
+
+; ARM-linux:      test_sibling_call_empty_frame:
+; ARM-linux:      bl      __morestack
+
+; ARM-android:      test_sibling_call_empty_frame:
+; ARM-android:      bl      __morestack
+
+}
+
 attributes #0 = { "split-stack" }