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author | Jakub Jelinek <jakub@redhat.com> | 2022-03-04 15:14:59 +0100 |
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committer | Jakub Jelinek <jakub@redhat.com> | 2022-03-04 15:14:59 +0100 |
commit | c85aaf2cbe9da50e23655a8082a37166adf4c0f7 (patch) | |
tree | 740b795d72aff22cb9e36d1692806144095cd7fe | |
parent | 07395f19dff610f03d1b1d30c8bd640f610c45dc (diff) | |
download | gcc-c85aaf2cbe9da50e23655a8082a37166adf4c0f7.zip gcc-c85aaf2cbe9da50e23655a8082a37166adf4c0f7.tar.gz gcc-c85aaf2cbe9da50e23655a8082a37166adf4c0f7.tar.bz2 |
gimplify: Clear TREE_READONLY on automatic vars being stored into [PR104529]
The following testcase regressed when SRA started punting on stores to
TREE_READONLY vars. We document that:
"In a VAR_DECL, PARM_DECL or FIELD_DECL, or any kind of ..._REF node,
nonzero means it may not be the lhs of an assignment."
so the SRA change looks desirable. On the other side, at least in this
testcase the TREE_READONLY is set there intentionally from the
PR85873 fix, because gimplify_init_constructor itself uses TREE_READONLY
on the object to determine if it can perform promotion to static const
or not.
So, similarly to other spots in the gimplifier where we also clear
TREE_READONLY when we emit IL that stores into the object, this
does the same in gimplify_init_constructor, but in the way so that
the TREE_READONLY test for the promotion to static const keeps working
and doesn't change anything for notify_temp_creation mode, which doesn't
emit any IL, just tests if it would need a temporary or not.
This keeps PR85873 testcase working as before and fixes this regression.
2022-03-04 Jakub Jelinek <jakub@redhat.com>
PR middle-end/104529
* gimplify.cc (gimplify_init_constructor): Clear TREE_READONLY
on automatic objects which will be runtime initialized.
* g++.dg/tree-ssa/pr104529.C: New test.
-rw-r--r-- | gcc/gimplify.cc | 11 | ||||
-rw-r--r-- | gcc/testsuite/g++.dg/tree-ssa/pr104529.C | 20 |
2 files changed, 31 insertions, 0 deletions
diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc index be8f0d3..c6ba0c3 100644 --- a/gcc/gimplify.cc +++ b/gcc/gimplify.cc @@ -5120,6 +5120,12 @@ gimplify_init_constructor (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p, { if (notify_temp_creation) return GS_OK; + + /* The var will be initialized and so appear on lhs of + assignment, it can't be TREE_READONLY anymore. */ + if (VAR_P (object)) + TREE_READONLY (object) = 0; + is_empty_ctor = true; break; } @@ -5171,6 +5177,11 @@ gimplify_init_constructor (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p, break; } + /* The var will be initialized and so appear on lhs of + assignment, it can't be TREE_READONLY anymore. */ + if (VAR_P (object) && !notify_temp_creation) + TREE_READONLY (object) = 0; + /* If there are "lots" of initialized elements, even discounting those that are not address constants (and thus *must* be computed at runtime), then partition the constructor into diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr104529.C b/gcc/testsuite/g++.dg/tree-ssa/pr104529.C new file mode 100644 index 0000000..3cb3853 --- /dev/null +++ b/gcc/testsuite/g++.dg/tree-ssa/pr104529.C @@ -0,0 +1,20 @@ +// PR middle-end/104529 +// { dg-do compile { target c++11 } } +// { dg-options "-O2 -fdump-tree-optimized" } +// { dg-final { scan-tree-dump-not "MEM\[^\n\r]*MEM" "optimized" } } + +#include <cstddef> +#include <vector> + +struct S { + unsigned int a; + std::vector<unsigned char> b; + std::vector<unsigned char> c; +}; + +std::size_t +foo () +{ + S test[] = { { 48, { 255, 0, 0, 0, 0, 0 } } }; + return sizeof (test); +} |