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llvm-mirror/test/CodeGen/AArch64/tailcc-tail-call.ll
Tim Northover fc5daa6083 IR/AArch64/X86: add "swifttailcc" calling convention.
Swift's new concurrency features are going to require guaranteed tail calls so
that they don't consume excessive amounts of stack space. This would normally
mean "tailcc", but there are also Swift-specific ABI desires that don't
naturally go along with "tailcc" so this adds another calling convention that's
the combination of "swiftcc" and "tailcc".

Support is added for AArch64 and X86 for now.
2021-05-17 10:48:34 +01:00

226 lines
6.7 KiB
LLVM

; RUN: llc -verify-machineinstrs < %s -mtriple=aarch64-none-linux-gnu | FileCheck %s --check-prefixes=SDAG,COMMON
; RUN: llc -global-isel -global-isel-abort=1 -verify-machineinstrs < %s -mtriple=aarch64-none-linux-gnu | FileCheck %s --check-prefixes=GISEL,COMMON
declare tailcc void @callee_stack0()
declare tailcc void @callee_stack8([8 x i64], i64)
declare tailcc void @callee_stack16([8 x i64], i64, i64)
declare extern_weak tailcc void @callee_weak()
define tailcc void @caller_to0_from0() nounwind {
; COMMON-LABEL: caller_to0_from0:
; COMMON-NEXT: // %bb.
tail call tailcc void @callee_stack0()
ret void
; COMMON-NEXT: b callee_stack0
}
define tailcc void @caller_to0_from8([8 x i64], i64) {
; COMMON-LABEL: caller_to0_from8:
tail call tailcc void @callee_stack0()
ret void
; COMMON: add sp, sp, #16
; COMMON-NEXT: b callee_stack0
}
define tailcc void @caller_to8_from0() "frame-pointer"="all"{
; COMMON-LABEL: caller_to8_from0:
; Key point is that the "42" should go #16 below incoming stack
; pointer (we didn't have arg space to reuse).
tail call tailcc void @callee_stack8([8 x i64] undef, i64 42)
ret void
; COMMON: str {{x[0-9]+}}, [x29, #16]
; COMMON: ldp x29, x30, [sp], #16
; If there is a sub here then the 42 will be briefly exposed to corruption
; from an interrupt if the kernel does not honour a red-zone, and a larger
; call could well overflow the red zone even if it is present.
; COMMON-NOT: sub sp,
; COMMON-NEXT: b callee_stack8
}
define tailcc void @caller_to8_from8([8 x i64], i64 %a) {
; COMMON-LABEL: caller_to8_from8:
; COMMON-NOT: sub sp,
; Key point is that the "%a" should go where at SP on entry.
tail call tailcc void @callee_stack8([8 x i64] undef, i64 42)
ret void
; COMMON: str {{x[0-9]+}}, [sp]
; COMMON-NEXT: b callee_stack8
}
define tailcc void @caller_to16_from8([8 x i64], i64 %a) {
; COMMON-LABEL: caller_to16_from8:
; COMMON-NOT: sub sp,
; Important point is that the call reuses the "dead" argument space
; above %a on the stack. If it tries to go below incoming-SP then the
; callee will not deallocate the space, even in tailcc.
tail call tailcc void @callee_stack16([8 x i64] undef, i64 42, i64 2)
; COMMON: stp {{x[0-9]+}}, {{x[0-9]+}}, [sp]
; COMMON-NEXT: b callee_stack16
ret void
}
define tailcc void @caller_to8_from24([8 x i64], i64 %a, i64 %b, i64 %c) {
; COMMON-LABEL: caller_to8_from24:
; COMMON-NOT: sub sp,
; Key point is that the "%a" should go where at #16 above SP on entry.
tail call tailcc void @callee_stack8([8 x i64] undef, i64 42)
ret void
; COMMON: str {{x[0-9]+}}, [sp, #16]!
; COMMON-NEXT: b callee_stack8
}
define tailcc void @caller_to16_from16([8 x i64], i64 %a, i64 %b) {
; COMMON-LABEL: caller_to16_from16:
; COMMON-NOT: sub sp,
; Here we want to make sure that both loads happen before the stores:
; otherwise either %a or %b will be wrongly clobbered.
tail call tailcc void @callee_stack16([8 x i64] undef, i64 %b, i64 %a)
ret void
; COMMON: ldp {{x[0-9]+}}, {{x[0-9]+}}, [sp]
; COMMON: stp {{x[0-9]+}}, {{x[0-9]+}}, [sp]
; COMMON-NEXT: b callee_stack16
}
define tailcc void @disable_tail_calls() nounwind "disable-tail-calls"="true" {
; COMMON-LABEL: disable_tail_calls:
; COMMON-NEXT: // %bb.
tail call tailcc void @callee_stack0()
ret void
; COMMON: bl callee_stack0
; COMMON: ret
}
; Weakly-referenced extern functions cannot be tail-called, as AAELF does
; not define the behaviour of branch instructions to undefined weak symbols.
define tailcc void @caller_weak() {
; COMMON-LABEL: caller_weak:
; COMMON: bl callee_weak
tail call void @callee_weak()
ret void
}
declare { [2 x float] } @get_vec2()
define { [3 x float] } @test_add_elem() {
; SDAG-LABEL: test_add_elem:
; SDAG: bl get_vec2
; SDAG: fmov s2, #1.0
; SDAG: ret
; GISEL-LABEL: test_add_elem:
; GISEL: str x30, [sp, #-16]!
; GISEL: bl get_vec2
; GISEL: fmov s2, #1.0
; GISEL: ldr x30, [sp], #16
; GISEL: ret
%call = tail call { [2 x float] } @get_vec2()
%arr = extractvalue { [2 x float] } %call, 0
%arr.0 = extractvalue [2 x float] %arr, 0
%arr.1 = extractvalue [2 x float] %arr, 1
%res.0 = insertvalue { [3 x float] } undef, float %arr.0, 0, 0
%res.01 = insertvalue { [3 x float] } %res.0, float %arr.1, 0, 1
%res.012 = insertvalue { [3 x float] } %res.01, float 1.000000e+00, 0, 2
ret { [3 x float] } %res.012
}
declare double @get_double()
define { double, [2 x double] } @test_mismatched_insert() {
; COMMON-LABEL: test_mismatched_insert:
; COMMON: bl get_double
; COMMON: bl get_double
; COMMON: bl get_double
; COMMON: ret
%val0 = call double @get_double()
%val1 = call double @get_double()
%val2 = tail call double @get_double()
%res.0 = insertvalue { double, [2 x double] } undef, double %val0, 0
%res.01 = insertvalue { double, [2 x double] } %res.0, double %val1, 1, 0
%res.012 = insertvalue { double, [2 x double] } %res.01, double %val2, 1, 1
ret { double, [2 x double] } %res.012
}
define void @fromC_totail() {
; COMMON-LABEL: fromC_totail:
; COMMON: sub sp, sp, #32
; COMMON-NOT: sub sp,
; COMMON: mov w[[TMP:[0-9]+]], #42
; COMMON: str x[[TMP]], [sp]
; COMMON: bl callee_stack8
; We must reset the stack to where it was before the call by undoing its extra stack pop.
; COMMON: str x[[TMP]], [sp, #-16]!
; COMMON: bl callee_stack8
; COMMON: sub sp, sp, #16
call tailcc void @callee_stack8([8 x i64] undef, i64 42)
call tailcc void @callee_stack8([8 x i64] undef, i64 42)
ret void
}
define void @fromC_totail_noreservedframe(i32 %len) {
; COMMON-LABEL: fromC_totail_noreservedframe:
; COMMON: stp x29, x30, [sp, #-32]!
; COMMON: mov w[[TMP:[0-9]+]], #42
; Note stack is subtracted here to allocate space for arg
; COMMON: str x[[TMP]], [sp, #-16]!
; COMMON: bl callee_stack8
; And here.
; COMMON: str x[[TMP]], [sp, #-16]!
; COMMON: bl callee_stack8
; But not restored here because callee_stack8 did that for us.
; COMMON-NOT: sub sp,
; Variable sized allocation prevents reserving frame at start of function so each call must allocate any stack space it needs.
%var = alloca i32, i32 %len
call tailcc void @callee_stack8([8 x i64] undef, i64 42)
call tailcc void @callee_stack8([8 x i64] undef, i64 42)
ret void
}
declare void @Ccallee_stack8([8 x i64], i64)
define tailcc void @fromtail_toC() {
; COMMON-LABEL: fromtail_toC:
; COMMON: sub sp, sp, #32
; COMMON-NOT: sub sp,
; COMMON: mov w[[TMP:[0-9]+]], #42
; COMMON: str x[[TMP]], [sp]
; COMMON: bl Ccallee_stack8
; C callees will return with the stack exactly where we left it, so we mustn't try to fix anything.
; COMMON-NOT: add sp,
; COMMON-NOT: sub sp,
; COMMON: str x[[TMP]], [sp]{{$}}
; COMMON: bl Ccallee_stack8
; COMMON-NOT: sub sp,
call void @Ccallee_stack8([8 x i64] undef, i64 42)
call void @Ccallee_stack8([8 x i64] undef, i64 42)
ret void
}