llvm-6502/test/CodeGen/AArch64/argument-blocks.ll
Tim Northover d7a4f74f15 AArch64: treat [N x Ty] as a block during procedure calls.
The AAPCS treats small structs and homogeneous floating (or vector) aggregates
specially, and guarantees they either get passed as a contiguous block of
registers, or prevent any future use of those registers and get passed on the
stack.

This concept can fit quite neatly into LLVM's own type system, mapping an HFA
to [N x float] and so on, and small structs to [N x i64]. Doing so allows
front-ends to emit AAPCS compliant code without having to duplicate the
register counting logic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222903 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-27 21:02:42 +00:00

93 lines
3.1 KiB
LLVM

; RUN: llc -mtriple=aarch64-apple-ios7.0 -o - %s | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-DARWINPCS
; RUN: llc -mtriple=aarch64-linux-gnu -o - %s | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-AAPCS
declare void @callee(...)
define float @test_hfa_regs(float, [2 x float] %in) {
; CHECK-LABEL: test_hfa_regs:
; CHECK: fadd s0, s1, s2
%lhs = extractvalue [2 x float] %in, 0
%rhs = extractvalue [2 x float] %in, 1
%sum = fadd float %lhs, %rhs
ret float %sum
}
; Check that the array gets allocated to a contiguous block on the stack (rather
; than the default of 2 8-byte slots).
define float @test_hfa_block([7 x float], [2 x float] %in) {
; CHECK-LABEL: test_hfa_block:
; CHECK: ldp [[LHS:s[0-9]+]], [[RHS:s[0-9]+]], [sp]
; CHECK: fadd s0, [[LHS]], [[RHS]]
%lhs = extractvalue [2 x float] %in, 0
%rhs = extractvalue [2 x float] %in, 1
%sum = fadd float %lhs, %rhs
ret float %sum
}
; Check that an HFA prevents backfilling of VFP registers (i.e. %rhs must go on
; the stack rather than in s7).
define float @test_hfa_block_consume([7 x float], [2 x float] %in, float %rhs) {
; CHECK-LABEL: test_hfa_block_consume:
; CHECK-DAG: ldr [[LHS:s[0-9]+]], [sp]
; CHECK-DAG: ldr [[RHS:s[0-9]+]], [sp, #8]
; CHECK: fadd s0, [[LHS]], [[RHS]]
%lhs = extractvalue [2 x float] %in, 0
%sum = fadd float %lhs, %rhs
ret float %sum
}
define float @test_hfa_stackalign([8 x float], [1 x float], [2 x float] %in) {
; CHECK-LABEL: test_hfa_stackalign:
; CHECK-AAPCS: ldp [[LHS:s[0-9]+]], [[RHS:s[0-9]+]], [sp, #8]
; CHECK-DARWINPCS: ldp [[LHS:s[0-9]+]], [[RHS:s[0-9]+]], [sp, #4]
; CHECK: fadd s0, [[LHS]], [[RHS]]
%lhs = extractvalue [2 x float] %in, 0
%rhs = extractvalue [2 x float] %in, 1
%sum = fadd float %lhs, %rhs
ret float %sum
}
; An HFA that ends up on the stack should not have any effect on where
; integer-based arguments go.
define i64 @test_hfa_ignores_gprs([7 x float], [2 x float] %in, i64, i64 %res) {
; CHECK-LABEL: test_hfa_ignores_gprs:
; CHECK: mov x0, x1
ret i64 %res
}
; [2 x float] should not be promoted to double by the Darwin varargs handling,
; but should go in an 8-byte aligned slot.
define void @test_varargs_stackalign() {
; CHECK-LABEL: test_varargs_stackalign:
; CHECK-DARWINPCS: stp {{w[0-9]+}}, {{w[0-9]+}}, [sp, #16]
call void(...)* @callee([3 x float] undef, [2 x float] [float 1.0, float 2.0])
ret void
}
define i64 @test_smallstruct_block([7 x i64], [2 x i64] %in) {
; CHECK-LABEL: test_smallstruct_block:
; CHECK: ldp [[LHS:x[0-9]+]], [[RHS:x[0-9]+]], [sp]
; CHECK: add x0, [[LHS]], [[RHS]]
%lhs = extractvalue [2 x i64] %in, 0
%rhs = extractvalue [2 x i64] %in, 1
%sum = add i64 %lhs, %rhs
ret i64 %sum
}
; Check that a small struct prevents backfilling of registers (i.e. %rhs
; must go on the stack rather than in x7).
define i64 @test_smallstruct_block_consume([7 x i64], [2 x i64] %in, i64 %rhs) {
; CHECK-LABEL: test_smallstruct_block_consume:
; CHECK-DAG: ldr [[LHS:x[0-9]+]], [sp]
; CHECK-DAG: ldr [[RHS:x[0-9]+]], [sp, #16]
; CHECK: add x0, [[LHS]], [[RHS]]
%lhs = extractvalue [2 x i64] %in, 0
%sum = add i64 %lhs, %rhs
ret i64 %sum
}