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| author | Vladimir N. Makarov <vmakarov@redhat.com> | 2023-09-25 16:19:50 -0400 |
|---|---|---|
| committer | Vladimir N. Makarov <vmakarov@redhat.com> | 2023-09-25 16:20:09 -0400 |
| commit | 3c23defed384cf17518ad6c817d94463a445d21b (patch) | |
| tree | b777ee78775055a3fe170d9ffc09403f82d2b6ba /gcc | |
| parent | 19df06f67c982b4e5427c4a056319d6a51c03481 (diff) | |
| download | gcc-3c23defed384cf17518ad6c817d94463a445d21b.zip gcc-3c23defed384cf17518ad6c817d94463a445d21b.tar.gz gcc-3c23defed384cf17518ad6c817d94463a445d21b.tar.bz2 | |
[PR111497][LRA]: Copy substituted equivalence
When we substitute the equivalence and it becomes shared, we can fail
to correctly update reg info used by LRA. This can result in wrong
code generation, e.g. because of incorrect live analysis. It can also
result in compiler crash as the pseudo survives RA. This is what
exactly happened for the PR. This patch solves this problem by
unsharing substituted equivalences.
gcc/ChangeLog:
PR middle-end/111497
* lra-constraints.cc (lra_constraints): Copy substituted
equivalence.
* lra.cc (lra): Change comment for calling unshare_all_rtl_again.
gcc/testsuite/ChangeLog:
PR middle-end/111497
* g++.target/i386/pr111497.C: new test.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/lra-constraints.cc | 5 | ||||
| -rw-r--r-- | gcc/lra.cc | 5 | ||||
| -rw-r--r-- | gcc/testsuite/g++.target/i386/pr111497.C | 22 |
3 files changed, 29 insertions, 3 deletions
diff --git a/gcc/lra-constraints.cc b/gcc/lra-constraints.cc index 3aaa490..76a1393 100644 --- a/gcc/lra-constraints.cc +++ b/gcc/lra-constraints.cc @@ -5424,6 +5424,11 @@ lra_constraints (bool first_p) loc_equivalence_callback, curr_insn); if (old != *curr_id->operand_loc[0]) { + /* If we substitute pseudo by shared equivalence, we can fail + to update LRA reg info and this can result in many + unexpected consequences. So keep rtl unshared: */ + *curr_id->operand_loc[0] + = copy_rtx (*curr_id->operand_loc[0]); lra_update_insn_regno_info (curr_insn); changed_p = true; } @@ -2579,9 +2579,8 @@ lra (FILE *f) if (inserted_p) commit_edge_insertions (); - /* Replacing pseudos with their memory equivalents might have - created shared rtx. Subsequent passes would get confused - by this, so unshare everything here. */ + /* Subsequent passes expect that rtl is unshared, so unshare everything + here. */ unshare_all_rtl_again (get_insns ()); if (flag_checking) diff --git a/gcc/testsuite/g++.target/i386/pr111497.C b/gcc/testsuite/g++.target/i386/pr111497.C new file mode 100644 index 0000000..a645bb9 --- /dev/null +++ b/gcc/testsuite/g++.target/i386/pr111497.C @@ -0,0 +1,22 @@ +// { dg-do compile { target ia32 } } +// { dg-options "-march=i686 -mtune=generic -fPIC -O2 -g" } + +class A; +struct B { const char *b1; int b2; }; +struct C : B { C (const char *x, int y) { b1 = x; b2 = y; } }; +struct D : C { D (B x) : C (x.b1, x.b2) {} }; +struct E { E (A *); }; +struct F : E { D f1, f2, f3, f4, f5, f6; F (A *, const B &, const B &, const B &); }; +struct G : F { G (A *, const B &, const B &, const B &); }; +struct H { int h; }; +struct I { H i; }; +struct J { I *j; }; +struct A : J {}; +inline F::F (A *x, const B &y, const B &z, const B &w) + : E(x), f1(y), f2(z), f3(w), f4(y), f5(z), f6(w) {} +G::G (A *x, const B &y, const B &z, const B &w) : F(x, y, z, w) +{ + H *h = &x->j->i; + if (h) + h->h++; +} |