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From: Nathan Sidwell <nathan@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc/devel/c++-modules] analyzer: fix pattern-test-2.c (PR 93291) Date: Fri, 31 Jan 2020 17:43:00 -0000 [thread overview] Message-ID: <20200131174313.2912.qmail@sourceware.org> (raw) https://gcc.gnu.org/g:f89e844f9c589d1717248597641d25d81a4acb41 commit f89e844f9c589d1717248597641d25d81a4acb41 Author: David Malcolm <dmalcolm@redhat.com> Date: Fri Jan 17 11:03:15 2020 -0500 analyzer: fix pattern-test-2.c (PR 93291) Amongst the inputs to the analyzer state machines that can lead to state transitions are conditions on CFG edges, such as a test for a pointer being non-NULL. These conditionals can be non-trivial to determine in the face of optimization. For example, at -O2: if (p == NULL || q == NULL) is optimized on some targets (e.g. x86_64) to a bitwise-or: _1 = p_5(D) == 0B; _2 = q_6(D) == 0B; _3 = _1 | _2; if (_3 != 0) goto <bb 4>; [51.12%] else goto <bb 3>; [48.88%] but on other targets (e.g. powerpc64le) as control flow: if (p_2(D) == 0B) goto <bb 5>; [18.09%] else goto <bb 3>; [81.91%] <bb 3> [local count: 879501929]: if (q_3(D) == 0B) goto <bb 5>; [30.95%] else goto <bb 4>; [69.05%] region_model::add_any_constraints_from_ssa_def_stmt attempts to walk SSA def chains to reconstruct the conditions that hold, so that e.g. in the above case of bitwise-or, the state machine for "p" can transition to the "known-null" state along the edge leading to bb 3. In gcc.dg/analyzer/pattern-test-2.c I attempted to write test coverage for this, but the test fails on those targets for which the || is expressed via control flow. This patch rewrites the test to make explicit use of bitwise-or, and adds coverage for bitwise-and for good measure. gcc/testsuite/ChangeLog: PR analyzer/93291 * gcc.dg/analyzer/pattern-test-2.c: Remove include of stdlib.h. (test_2): Rewrite to explicitly perform a bitwise-or of two boolean conditions. (test_3): New function, to test bitwise-and. Diff: --- gcc/testsuite/ChangeLog | 8 +++++++ gcc/testsuite/gcc.dg/analyzer/pattern-test-2.c | 30 +++++++++++++++++++++++--- 2 files changed, 35 insertions(+), 3 deletions(-) diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 4359aa1..56acbd9 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,11 @@ +2020-01-27 David Malcolm <dmalcolm@redhat.com> + + PR analyzer/93291 + * gcc.dg/analyzer/pattern-test-2.c: Remove include of stdlib.h. + (test_2): Rewrite to explicitly perform a bitwise-or of two + boolean conditions. + (test_3): New function, to test bitwise-and. + 2020-01-27 Richard Sandiford <richard.sandiford@arm.com> PR testsuite/71727 diff --git a/gcc/testsuite/gcc.dg/analyzer/pattern-test-2.c b/gcc/testsuite/gcc.dg/analyzer/pattern-test-2.c index ffc06a2..f5424f5 100644 --- a/gcc/testsuite/gcc.dg/analyzer/pattern-test-2.c +++ b/gcc/testsuite/gcc.dg/analyzer/pattern-test-2.c @@ -1,8 +1,6 @@ /* { dg-additional-options "-fanalyzer-checker=pattern-test -O2" } */ // TODO: run this at every optimization level -#include <stdlib.h> - extern void foo(void *); extern void bar(void *); @@ -18,12 +16,38 @@ void test1(void *ptr) void test_2 (void *p, void *q) { - if (p == NULL || q == NULL) /* { dg-line cond_2 } */ + _Bool tmp1 = p == 0; + _Bool tmp2 = q == 0; + _Bool tmp = tmp1 | tmp2; + + /* Verify that we can detect the implied conditions on p and q here. */ + if (tmp) /* { dg-line cond_2 } */ return; foo(p); + /* { dg-warning "pattern match on 'tmp1 == 0'" "tmp1 == 0" { target *-*-* } cond_2 } */ + /* { dg-warning "pattern match on 'tmp2 == 0'" "tmp2 == 0" { target *-*-* } cond_2 } */ /* { dg-warning "pattern match on '<unknown> == 0'" "<unknown> == 0" { target *-*-* } cond_2 } */ /* { dg-warning "pattern match on '<unknown> != 0'" "<unknown> != 0" { target *-*-* } cond_2 } */ /* { dg-warning "pattern match on 'p != 0'" "p != 0" { target *-*-* } cond_2 } */ /* { dg-warning "pattern match on 'q != 0'" "q != 0" { target *-*-* } cond_2 } */ } + +void test_3 (void *p, void *q) +{ + _Bool tmp1 = p == 0; + _Bool tmp2 = q == 0; + _Bool tmp = tmp1 & tmp2; + + /* Verify that we can detect the implied conditions on p and q here. */ + if (tmp) /* { dg-line cond_3 } */ + return; + foo(p); + + /* { dg-warning "pattern match on 'tmp1 != 0'" "tmp1 != 0" { target *-*-* } cond_3 } */ + /* { dg-warning "pattern match on 'tmp2 != 0'" "tmp2 != 0" { target *-*-* } cond_3 } */ + /* { dg-warning "pattern match on '<unknown> == 0'" "<unknown> == 0" { target *-*-* } cond_3 } */ + /* { dg-warning "pattern match on '<unknown> != 0'" "<unknown> != 0" { target *-*-* } cond_3 } */ + /* { dg-warning "pattern match on 'p == 0'" "p == 0" { target *-*-* } cond_3 } */ + /* { dg-warning "pattern match on 'q == 0'" "q == 0" { target *-*-* } cond_3 } */ +}
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