llvm/test/CodeGen/ARM/jump-table-islands.ll
Tim Northover 9962fd0e2e ARM: allow jump tables to be placed as constant islands.
Previously, they were forced to immediately follow the actual branch
instruction. This was usually OK (the LEAs actually accessing them got emitted
nearby, and weren't usually separated much afterwards). Unfortunately, a
sufficiently nasty phi elimination dumps many instructions right before the
basic block terminator, and this can increase the range too much.

This patch frees them up to be placed as usual by the constant islands pass,
and consequently has to slightly modify the form of TBB/TBH tables to refer to
a PC-relative label at the final jump. The other jump table formats were
already position-independent.

rdar://20813304

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237590 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-18 17:10:40 +00:00

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939 B
LLVM

; RUN: llc -mtriple=armv7-apple-ios8.0 -o - %s | FileCheck %s
%BigInt = type i5500
define %BigInt @test_moved_jumptable(i1 %tst, i32 %sw, %BigInt %l) {
; CHECK-LABEL: test_moved_jumptable:
; CHECK: adr {{r[0-9]+}}, [[JUMP_TABLE:LJTI[0-9]+_[0-9]+]]
; CHECK: b [[SKIP_TABLE:LBB[0-9]+_[0-9]+]]
; CHECK: [[JUMP_TABLE]]:
; CHECK: .data_region jt32
; CHECK: .long LBB{{[0-9]+_[0-9]+}}-[[JUMP_TABLE]]
; CHECK: [[SKIP_TABLE]]:
; CHECK: add pc, {{r[0-9]+}}, {{r[0-9]+}}
br i1 %tst, label %simple, label %complex
simple:
br label %end
complex:
switch i32 %sw, label %simple [ i32 0, label %other
i32 1, label %third
i32 5, label %end
i32 6, label %other ]
third:
ret %BigInt 0
other:
call void @bar()
unreachable
end:
%val = phi %BigInt [ %l, %complex ], [ -1, %simple ]
ret %BigInt %val
}
declare void @bar()