From 665c5bad168ab63629b29ed2ce08ed042c088dc2 Mon Sep 17 00:00:00 2001 From: Martin Jambor Date: Wed, 19 Feb 2020 11:08:40 +0100 Subject: [PATCH] sra: Avoid totally scalarizing overallping field_decls (PR 93667) [[no_unique_address]] C++ attribute can cause two fields of a RECORD_TYPE overlap, which currently confuses the totally scalarizing code into creating invalid access tree. For GCC 10, I'd like to simply disable total scalarization of types where this happens. For GCC 11 I'll write down a TODO item to enable total scalarization of cases like this where the problematic fields are basically empty - despite having a non-zero size - i.e. when they are just RECORD_TYPEs without any data fields. 2020-02-19 Martin Jambor gcc/ PR tree-optimization/93667 * tree-sra.c (scalarizable_type_p): Return false if record fields do not follow wach other. gcc/testsuite/ PR tree-optimization/93667 * g++.dg/tree-ssa/pr93667.C: New test. --- gcc/ChangeLog | 6 ++++++ gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/g++.dg/tree-ssa/pr93667.C | 11 +++++++++++ gcc/tree-sra.c | 14 ++++++++++++++ 4 files changed, 36 insertions(+) create mode 100644 gcc/testsuite/g++.dg/tree-ssa/pr93667.C diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 77c2a9ad810..6b53f9a2f07 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2020-02-19 Martin Jambor + + PR tree-optimization/93667 + * tree-sra.c (scalarizable_type_p): Return false if record fields + do not follow wach other. + 2020-01-21 Kito Cheng * config/riscv/riscv.c (riscv_output_move) Using fmv.x.w/fmv.w.x diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 9b4fe11a6f6..8033fa0a3bb 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2020-02-19 Martin Jambor + + PR tree-optimization/93667 + * g++.dg/tree-ssa/pr93667.C: New test. + 2020-02-19 Hongtao Liu * g++.dg/other/i386-2.C: add -mavx512vbmi2 diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr93667.C b/gcc/testsuite/g++.dg/tree-ssa/pr93667.C new file mode 100644 index 00000000000..d875f53d9ec --- /dev/null +++ b/gcc/testsuite/g++.dg/tree-ssa/pr93667.C @@ -0,0 +1,11 @@ +// { dg-do compile } +// { dg-options "-O2 -std=c++2a" } */ + +struct a {}; +struct b { [[no_unique_address]] a aq; }; +struct c { + int d; + [[no_unique_address]] b e; +}; +c f() {return {};} +void g() { f(); } diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c index 0cfac0a8192..4c7d651e6b9 100644 --- a/gcc/tree-sra.c +++ b/gcc/tree-sra.c @@ -958,6 +958,9 @@ scalarizable_type_p (tree type, bool const_decl) if (type_contains_placeholder_p (type)) return false; + bool have_predecessor_field = false; + HOST_WIDE_INT prev_pos = 0; + switch (TREE_CODE (type)) { case RECORD_TYPE: @@ -966,6 +969,17 @@ scalarizable_type_p (tree type, bool const_decl) { tree ft = TREE_TYPE (fld); + if (zerop (DECL_SIZE (fld))) + continue; + + HOST_WIDE_INT pos = int_bit_position (fld); + if (have_predecessor_field + && pos <= prev_pos) + return false; + + have_predecessor_field = true; + prev_pos = pos; + if (DECL_BIT_FIELD (fld)) return false; -- 2.30.2