1 files changed, 62 insertions, 0 deletions
diff --git a/test/CodeGen/X86/huge-stack-offset2.ll b/test/CodeGen/X86/huge-stack-offset2.ll
new file mode 100644
index 000000000000..9ac85b618dbd
--- /dev/null
+++ b/test/CodeGen/X86/huge-stack-offset2.ll
@@ -0,0 +1,62 @@
+; RUN: llc < %s -mtriple=x86_64-linux | FileCheck %s --check-prefix=CHECK
+
+; Test how we handle pathologically large stack frames when RAX is live through
+; the prologue and epilogue.
+
+declare void @bar(i8*)
+declare void @llvm.va_start(i8*)
+
+; For stack frames between 2GB and 16GB, do multiple adjustments.
+
+define i32 @stack_frame_8gb(i32 %x, ...) nounwind {
+; CHECK-LABEL: stack_frame_8gb:
+; CHECK:      subq ${{.*}}, %rsp # imm = 0x7FFFFFFF
+; CHECK:      subq ${{.*}}, %rsp # imm = 0x7FFFFFFF
+; CHECK:      subq ${{.*}}, %rsp # imm = 0x7FFFFFFF
+; CHECK:      subq ${{.*}}, %rsp # imm = 0x7FFFFFFF
+; CHECK:      subq ${{.*}}, %rsp
+; CHECK:      callq bar
+; CHECK:      addq ${{.*}}, %rsp # imm = 0x7FFFFFFF
+; CHECK:      addq ${{.*}}, %rsp # imm = 0x7FFFFFFF
+; CHECK:      addq ${{.*}}, %rsp # imm = 0x7FFFFFFF
+; CHECK:      addq ${{.*}}, %rsp # imm = 0x7FFFFFFF
+; CHECK:      addq ${{.*}}, %rsp
+; CHECK:      retq
+  %1 = alloca [u0x200000000 x i8]
+  %va = alloca i8, i32 24
+  call void @llvm.va_start(i8* %va)
+  %2 = getelementptr inbounds [u0x200000000 x i8], [u0x200000000 x i8]* %1, i32 0, i32 0
+  call void @bar(i8* %2)
+  ret i32 %x
+}
+
+; For stack frames larger than 16GB, spill EAX instead of doing a linear number
+; of adjustments.
+
+; This function should have a frame size of 0x4000000D0. The 0xD0 is 208 bytes
+; from 24 bytes of va_list, 176 bytes of spilled varargs regparms, and 8 bytes
+; of alignment. We subtract 8 less and add 8 more in the prologue and epilogue
+; respectively to account for the PUSH.
+
+define i32 @stack_frame_16gb(i32 %x, ...) nounwind {
+; CHECK-LABEL: stack_frame_16gb:
+; CHECK:      pushq %rax
+; CHECK-NEXT: movabsq ${{.*}}, %rax # imm = 0xFFFFFFFBFFFFFF38
+; CHECK-NEXT: addq %rsp, %rax
+; CHECK-NEXT: xchgq %rax, (%rsp)
+; CHECK-NEXT: movq (%rsp), %rsp
+; CHECK:      callq bar
+; CHECK:      pushq %rax
+; CHECK-NEXT: movabsq ${{.*}}, %rax # imm = 0x4000000D8
+; CHECK-NEXT: addq %rsp, %rax
+; CHECK-NEXT: xchgq %rax, (%rsp)
+; CHECK-NEXT: movq (%rsp), %rsp
+; CHECK:      retq
+  %1 = alloca [u0x400000000 x i8]
+  %va = alloca i8, i32 24
+  call void @llvm.va_start(i8* %va)
+  %2 = getelementptr inbounds [u0x400000000 x i8], [u0x400000000 x i8]* %1, i32 0, i32 0
+  call void @bar(i8* %2)
+  ret i32 %x
+}
+