c091a695e6
When we detect interference between the values that have already been merged into the candidate virtual register and an EBB argument, we first try to resolve the conflict by splitting. We also check if the existing interfering value is fundamentally incompatible with the branch instruction so it needs to be removed from the virtual register, restarting the merge operation. However, this existing interfering value is not necessarily the only interference, so the split is not guaranteed to resolve the conflict. If it turns out that splitting didn't resolve the conflict, restart the merge after removing this second conflicting value.
125 lines
2.9 KiB
Plaintext
125 lines
2.9 KiB
Plaintext
test regalloc
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isa riscv
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; Test the coalescer.
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; regex: V=v\d+
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; regex: WS=\s+
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; regex: LOC=%\w+
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; This function is already CSSA, so no copies should be inserted.
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function %cssa(i32) -> i32 {
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ebb0(v0: i32):
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; not: copy
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; v0 is used by the branch and passed as an arg - that's no conflict.
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brnz v0, ebb1(v0)
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; v0 is live across the branch above. That's no conflict.
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v1 = iadd_imm v0, 7
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jump ebb1(v1)
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ebb1(v10: i32):
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v11 = iadd_imm v10, 7
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return v11
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}
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function %trivial(i32) -> i32 {
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ebb0(v0: i32):
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; check: $(cp1=$V) = copy $v0
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; nextln: brnz $v0, $ebb1($cp1)
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brnz v0, ebb1(v0)
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; not: copy
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v1 = iadd_imm v0, 7
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jump ebb1(v1)
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ebb1(v10: i32):
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; Use v0 in the destination EBB causes a conflict.
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v11 = iadd v10, v0
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return v11
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}
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; A value is used as an SSA argument twice in the same branch.
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function %dualuse(i32) -> i32 {
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ebb0(v0: i32):
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; check: $(cp1=$V) = copy $v0
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; nextln: brnz $v0, $ebb1($v0, $cp1)
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brnz v0, ebb1(v0, v0)
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; not: copy
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v1 = iadd_imm v0, 7
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v2 = iadd_imm v1, 56
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jump ebb1(v1, v2)
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ebb1(v10: i32, v11: i32):
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v12 = iadd v10, v11
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return v12
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}
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; Interference away from the branch
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; The interference can be broken with a copy at either branch.
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function %interference(i32) -> i32 {
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ebb0(v0: i32):
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; not: copy
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brnz v0, ebb1(v0)
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v1 = iadd_imm v0, 7
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; v1 and v0 interfere here:
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v2 = iadd_imm v0, 8
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; check: $(cp1=$V) = copy $v1
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; not: copy
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; check: jump $ebb1($cp1)
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jump ebb1(v1)
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ebb1(v10: i32):
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; not: copy
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v11 = iadd_imm v10, 7
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return v11
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}
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; A loop where one induction variable is used as a backedge argument.
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function %fibonacci(i32) -> i32 {
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ebb0(v0: i32):
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; not: copy
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v1 = iconst.i32 1
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v2 = iconst.i32 2
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jump ebb1(v1, v2)
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ebb1(v10: i32, v11: i32):
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; v11 needs to be isolated because it interferes with v10.
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; check: $ebb1($v10: i32 [$LOC], $(nv11a=$V): i32 [$LOC])
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; check: $v11 = copy $nv11a
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v12 = iadd v10, v11
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v13 = icmp ult v12, v0
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; check: $(nv11b=$V) = copy $v11
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; not: copy
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; check: brnz $v13, $ebb1($nv11b, $v12)
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brnz v13, ebb1(v11, v12)
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return v12
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}
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; Function arguments passed on the stack aren't allowed to be part of a virtual
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; register, at least for now. This is because the other values in the virtual
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; register would need to be spilled to the incoming_arg stack slot which we treat
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; as belonging to the caller.
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function %stackarg(i32, i32, i32, i32, i32, i32, i32, i32, i32) -> i32 {
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; check: ss0 = incoming_arg 4
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; not: incoming_arg
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ebb0(v0: i32, v1: i32, v2: i32, v3: i32, v4: i32, v5: i32, v6: i32, v7: i32, v8: i32):
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; check: fill v8
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; not: v8
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brnz v0, ebb1(v8)
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jump ebb1(v7)
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ebb1(v10: i32):
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v11 = iadd_imm v10, 1
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return v11
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}
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function %gvn_unremovable_phi(i32) native {
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ebb0(v0: i32):
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v2 = iconst.i32 0
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jump ebb2(v2, v0)
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ebb2(v3: i32, v4: i32):
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brnz v3, ebb2(v3, v4)
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v5 = iconst.i32 1
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brnz v3, ebb2(v2, v5)
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return
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}
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