Implement -disable-non-leaf-fp-elim which disable frame pointer elimination

optimization for non-leaf functions. This will be hooked up to gcc's
-momit-leaf-frame-pointer option. rdar://7886181

llvm-svn: 101984

1 files changed, 44 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/fp-elim.ll b/llvm/test/CodeGen/X86/fp-elim.ll
new file mode 100644
index 00000000000..60892a2352f
--- /dev/null
+++ b/llvm/test/CodeGen/X86/fp-elim.ll
@@ -0,0 +1,44 @@
+; RUN: llc < %s -march=x86 -asm-verbose=false                           | FileCheck %s -check-prefix=FP-ELIM
+; RUN: llc < %s -march=x86 -asm-verbose=false -disable-fp-elim          | FileCheck %s -check-prefix=NO-ELIM
+; RUN: llc < %s -march=x86 -asm-verbose=false -disable-non-leaf-fp-elim | FileCheck %s -check-prefix=NON-LEAF
+
+; Implement -momit-leaf-frame-pointer
+; rdar://7886181
+
+define i32 @t1() nounwind readnone {
+entry:
+; FP-ELIM:      t1:
+; FP-ELIM-NEXT: movl
+; FP-ELIM-NEXT: ret
+
+; NO-ELIM:      t1:
+; NO-ELIM-NEXT: pushl %ebp
+; NO-ELIM:      popl %ebp
+; NO-ELIM-NEXT: ret
+
+; NON-LEAF:      t1:
+; NON-LEAF-NEXT: movl
+; NON-LEAF-NEXT: ret
+  ret i32 10
+}
+
+define void @t2() nounwind {
+entry:
+; FP-ELIM:     t2:
+; FP-ELIM-NOT: pushl %ebp
+; FP-ELIM:     ret
+
+; NO-ELIM:      t2:
+; NO-ELIM-NEXT: pushl %ebp
+; NO-ELIM:      popl %ebp
+; NO-ELIM-NEXT: ret
+
+; NON-LEAF:      t2:
+; NON-LEAF-NEXT: pushl %ebp
+; NON-LEAF:      popl %ebp
+; NON-LEAF-NEXT: ret
+  tail call void @foo(i32 0) nounwind
+  ret void
+}
+
+declare void @foo(i32)