From 1956773cc655dfcba8d310066d3f6585dd4b8972 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Thu, 27 Feb 2020 10:45:30 +0100 Subject: [PATCH] gimplify: Don't optimize register const vars to static [PR93949] The following testcase is rejected, while it was accepted in 3.4 and earlier (before tree-ssa merge). The problem is that we decide to promote the const variable to TREE_STATIC, but TREE_STATIC DECL_REGISTER VAR_DECLs may only be the global register vars and so assemble_variable/make_decl_rtl diagnoses it. Either we do what the following patch does, where we could consider register as a hint the user doesn't want such optimization, because if something is forced static, it is not "register" anymore and register static is not valid in C either, or we could clear DECL_REGISTER instead, but would still need to punt at least on DECL_HARD_REGISTER cases. 2020-02-27 Jakub Jelinek PR c/93949 * gimplify.c (gimplify_init_constructor): Don't promote readonly DECL_REGISTER variables to TREE_STATIC. * gcc.c-torture/compile/pr93949.c: New test. --- gcc/ChangeLog | 4 ++++ gcc/gimplify.c | 1 + gcc/testsuite/ChangeLog | 3 +++ gcc/testsuite/gcc.c-torture/compile/pr93949.c | 7 +++++++ 4 files changed, 15 insertions(+) create mode 100644 gcc/testsuite/gcc.c-torture/compile/pr93949.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 38bfbb95474..d8cfd09daa8 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,9 @@ 2020-02-27 Jakub Jelinek + PR c/93949 + * gimplify.c (gimplify_init_constructor): Don't promote readonly + DECL_REGISTER variables to TREE_STATIC. + PR tree-optimization/93582 PR tree-optimization/93945 * tree-ssa-sccvn.c (vn_reference_lookup_3): Handle memset with diff --git a/gcc/gimplify.c b/gcc/gimplify.c index a6205d69701..ef531f3fd7b 100644 --- a/gcc/gimplify.c +++ b/gcc/gimplify.c @@ -4923,6 +4923,7 @@ gimplify_init_constructor (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p, && num_nonzero_elements > 1 && TREE_READONLY (object) && VAR_P (object) + && !DECL_REGISTER (object) && (flag_merge_constants >= 2 || !TREE_ADDRESSABLE (object)) /* For ctors that have many repeated nonzero elements represented through RANGE_EXPRs, prefer initializing diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 70897c5f94c..3cc13f91949 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,8 @@ 2020-02-27 Jakub Jelinek + PR c/93949 + * gcc.c-torture/compile/pr93949.c: New test. + PR tree-optimization/93582 PR tree-optimization/93945 * gcc.dg/tree-ssa/pr93582-9.c: New test. diff --git a/gcc/testsuite/gcc.c-torture/compile/pr93949.c b/gcc/testsuite/gcc.c-torture/compile/pr93949.c new file mode 100644 index 00000000000..bbda0209802 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/compile/pr93949.c @@ -0,0 +1,7 @@ +/* PR c/93949 */ + +void +foo (void) +{ + register const double d[3] = { 0., 1., 2. }; +} -- 2.30.2