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| author | Hans-Peter Nilsson <hp@axis.com> | 2020-07-05 20:50:52 +0200 |
|---|---|---|
| committer | Hans-Peter Nilsson <hp@axis.com> | 2020-07-13 08:08:39 +0200 |
| commit | a4aca1edaf37d43b2b7e9111825837a7a317b1b0 (patch) | |
| tree | cc00c01e5050a71797365b84d0b943b1baec2f40 /gcc/expr.c | |
| parent | 56d78c58c233a358c780571ad6fecbabdcff2407 (diff) | |
| download | gcc-a4aca1edaf37d43b2b7e9111825837a7a317b1b0.zip gcc-a4aca1edaf37d43b2b7e9111825837a7a317b1b0.tar.gz gcc-a4aca1edaf37d43b2b7e9111825837a7a317b1b0.tar.bz2 | |
PR94600: fix volatile access to the whole of a compound object.
The store to the whole of each volatile object was picked apart
like there had been an individual assignment to each of the
fields. Reads were added as part of that; see PR for details.
The reads from volatile memory were a clear bug; individual
stores questionable. A separate patch clarifies the docs.
gcc:
2020-07-09 Richard Biener <rguenther@suse.de>
PR middle-end/94600
* expr.c (expand_constructor): Make a temporary also if we're
storing to volatile memory.
gcc/testsuite:
2020-07-09 Hans-Peter Nilsson <hp@axis.com>
PR middle-end/94600
* gcc.dg/pr94600-1.c, gcc.dg/pr94600-2.c, gcc.dg/pr94600-3.c,
gcc.dg/pr94600-4.c, gcc.dg/pr94600-5.c, gcc.dg/pr94600-6.c,
gcc.dg/pr94600-7.c, gcc.dg/pr94600-8.c: New tests.
Diffstat (limited to 'gcc/expr.c')
| -rw-r--r-- | gcc/expr.c | 5 |
1 files changed, 4 insertions, 1 deletions
@@ -8379,7 +8379,10 @@ expand_constructor (tree exp, rtx target, enum expand_modifier modifier, /* Handle calls that pass values in multiple non-contiguous locations. The Irix 6 ABI has examples of this. */ if (target == 0 || ! safe_from_p (target, exp, 1) - || GET_CODE (target) == PARALLEL || modifier == EXPAND_STACK_PARM) + || GET_CODE (target) == PARALLEL || modifier == EXPAND_STACK_PARM + /* Also make a temporary if the store is to volatile memory, to + avoid individual accesses to aggregate members. */ + || (GET_CODE (target) == MEM && MEM_VOLATILE_P (target))) { if (avoid_temp_mem) return NULL_RTX; |