1c235c3754
This patch adds tail call support to the 32-bit Sparc backend. Two new instructions are defined, TAIL_CALL and TAIL_CALLri. They are encoded the same as CALL and BINDri, but are marked with isReturn so that the epilogue gets emitted. In contrast to CALL, TAIL_CALL is not marked with isCall. This makes it possible to use the leaf function optimization when the only call a function makes is a tail call. TAIL_CALL modifies the return address in %o7, so for leaf functions the value in %o7 needs to be restored after the call. For normal functions which uses the restore instruction this is not necessary. Reviewed By: koakuma Differential Revision: https://reviews.llvm.org/D51206
53 lines
1.0 KiB
LLVM
53 lines
1.0 KiB
LLVM
; RUN: llc -march=sparc -O0 <%s
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; RUN: llc -march=sparc <%s | FileCheck %s --check-prefix=V8
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; RUN: llc -march=sparcv9 <%s | FileCheck %s --check-prefix=V9
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; V8-LABEL: test
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; V8: save %sp
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; V8: call foo
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; V8-NEXT: nop
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; V8: call bar
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; V8-NEXT: nop
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; V8: ret
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; V8-NEXT: restore
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; V9-LABEL: test
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; V9: save %sp
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; V9: call foo
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; V9-NEXT: nop
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; V9: call bar
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; V9-NEXT: nop
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; V9: ret
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; V9-NEXT: restore
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define void @test() #0 {
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entry:
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%0 = tail call i32 (...) @foo() nounwind
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tail call void (...) @bar() nounwind
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ret void
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}
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declare i32 @foo(...)
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declare void @bar(...)
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; V8-LABEL: test_tail_call_with_return
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; V8: mov %o7, %g1
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; V8-NEXT: call foo
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; V8-NEXT: mov %g1, %o7
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; V9-LABEL: test_tail_call_with_return
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; V9: save %sp
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; V9: call foo
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; V9-NEXT: nop
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; V9: ret
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; V9-NEXT: restore %g0, %o0, %o0
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define i32 @test_tail_call_with_return() nounwind {
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entry:
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%0 = tail call i32 (...) @foo() nounwind
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ret i32 %0
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}
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attributes #0 = { nounwind "disable-tail-calls"="true" }
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