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559d1ea5ce
Estimated hours taken: 1
Fix a bug in value numbering reported by Simon.
compiler/vn_block.m:
Restore a previously commented block of code, whose job is to force
the flushing of any stack slot that holds the saved value of a nondet
control register or stack slot. The rationale for this code used
to be the handling of cuts in nondet code; now it is the handling
of hijackings.
tests/hard_coded.{m,exp}:
A cut-down and inlined version of Simon's test case, which fails
without the change to vn_block and succeeds with it.
tests/hard_coded/Mmakefile:
Enable the new test case, and require that it be compiled with
value numbering.
42 lines
752 B
Mathematica
42 lines
752 B
Mathematica
% This is a regression test. The 1998 August 24 version of the compiler
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% generated incorrect code for this module, the bug being that the value
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% numbering pass did not properly flush stack slots that hold the old values
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% of hijacked nondet control slots.
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%
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% This is a cut-down version of cut_test.m
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:- module nondet_ctrl_vn.
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:- interface.
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:- import_module io.
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:- pred main(io__state::di, io__state::uo) is det.
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:- implementation.
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:- import_module int.
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main -->
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( { middle(100) } ->
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io__write_string("test succeeded: BUG.\n")
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;
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io__write_string("test failed: OK.\n")
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).
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:- pragma no_inline(middle/1).
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:- pred middle(int::in) is semidet.
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middle(A0) :-
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(
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A is A0 + 10
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;
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A is A0 + 20
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),
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A > 200,
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(
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B is A
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;
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B is A * 2
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).
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