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| author | Bernd Edlinger <bernd.edlinger@hotmail.de> | 2013-12-02 19:50:55 +0000 |
|---|---|---|
| committer | Bernd Edlinger <edlinger@gcc.gnu.org> | 2013-12-02 19:50:55 +0000 |
| commit | 2399cad0909d5753f774f670a19efd329d020b3b (patch) | |
| tree | 569bc9e6949ab42a3b0713707ffc43092cf900ed /gcc | |
| parent | 72ee07fb7620604030a5713bf8967af64dfbe5c2 (diff) | |
| download | gcc-2399cad0909d5753f774f670a19efd329d020b3b.zip gcc-2399cad0909d5753f774f670a19efd329d020b3b.tar.gz gcc-2399cad0909d5753f774f670a19efd329d020b3b.tar.bz2 | |
Fix C++0x memory model for unaligned fields in packed...
2013-12-02 Bernd Edlinger <bernd.edlinger@hotmail.de>
Fix C++0x memory model for unaligned fields in packed, aligned(4)
structures with -fno-strict-volatile-bitfields on STRICT_ALIGNMENT
targets like arm-none-eabi.
* expr.c (expand_assignment): Handle normal fields like bit regions.
testsuite:
2013-12-02 Bernd Edlinger <bernd.edlinger@hotmail.de>
* gcc.dg/pr56997-4.c: New testcase.
From-SVN: r205597
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/expr.c | 11 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/pr56997-4.c | 23 |
4 files changed, 45 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 84153b0..21b8aa3 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,12 @@ 2013-12-02 Bernd Edlinger <bernd.edlinger@hotmail.de> + Fix C++0x memory model for unaligned fields in packed, aligned(4) + structures with -fno-strict-volatile-bitfields on STRICT_ALIGNMENT + targets like arm-none-eabi. + * expr.c (expand_assignment): Handle normal fields like bit regions. + +2013-12-02 Bernd Edlinger <bernd.edlinger@hotmail.de> + PR target/58115 * function.c (invoke_set_current_function_hook): Call targetm.set_current_function after setting this_fn_optabs. @@ -4824,6 +4824,17 @@ expand_assignment (tree to, tree from, bool nontemporal) if (TREE_CODE (to) == COMPONENT_REF && DECL_BIT_FIELD_TYPE (TREE_OPERAND (to, 1))) get_bit_range (&bitregion_start, &bitregion_end, to, &bitpos, &offset); + /* The C++ memory model naturally applies to byte-aligned fields. + However, if we do not have a DECL_BIT_FIELD_TYPE but BITPOS or + BITSIZE are not byte-aligned, there is no need to limit the range + we can access. This can occur with packed structures in Ada. */ + else if (bitsize > 0 + && bitsize % BITS_PER_UNIT == 0 + && bitpos % BITS_PER_UNIT == 0) + { + bitregion_start = bitpos; + bitregion_end = bitpos + bitsize - 1; + } to_rtx = expand_expr (tem, NULL_RTX, VOIDmode, EXPAND_WRITE); diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 9c7be13..f92967a 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2013-12-02 Bernd Edlinger <bernd.edlinger@hotmail.de> + + * gcc.dg/pr56997-4.c: New testcase. + 2013-12-02 Marek Polacek <polacek@redhat.com> * c-c++-common/ubsan/vla-1.c: Split the tests into individual diff --git a/gcc/testsuite/gcc.dg/pr56997-4.c b/gcc/testsuite/gcc.dg/pr56997-4.c new file mode 100644 index 0000000..38f6248 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr56997-4.c @@ -0,0 +1,23 @@ +/* Test volatile access to unaligned field. */ +/* { dg-do compile } */ +/* { dg-options "-fno-strict-volatile-bitfields -fdump-rtl-final" } */ + +#define test_type unsigned short + +typedef struct s{ + unsigned char Prefix[1]; + volatile test_type Type; +}__attribute((__packed__,__aligned__(4))) ss; + +extern volatile ss v; + +void +foo (test_type u) +{ + v.Type = u; +} + +/* The C++ memory model forbids data store race conditions outside the + unaligned data member, therefore only QI or HI access is allowed, no SI. */ +/* { dg-final { scan-rtl-dump-not "mem/v(/.)*:SI" "final" } } */ +/* { dg-final { cleanup-rtl-dump "final" } } */ |