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| author | Francisco Jerez <currojerez@riseup.net> | 2018-01-26 11:48:02 -0800 |
|---|---|---|
| committer | Francisco Jerez <currojerez@riseup.net> | 2018-02-27 11:42:39 -0800 |
| commit | cb309d27c52e9a6eeeedbddb82a0f6eb75a6f263 (patch) | |
| tree | 26876a8343d5d645773fd5dda9d9ace97724abaa /src/intel/compiler/test_eu_compact.cpp | |
| parent | 69b4a9d21d00e1f72b52e818cc059ee1642f263e (diff) | |
| download | mesa-cb309d27c52e9a6eeeedbddb82a0f6eb75a6f263.tar.gz | |
intel/ir: Fix invalid type aliasing with undefined behavior in test_eu_compact.
test_fuzz_compact_instruction() was attempting to modify the uint64_t
data array of a brw_inst through a pointer to uint32_t, which has
undefined behavior. This was causing the test_eu_compact unit test to
fail mysteriously for me on GCC 7 with some additional
harmless-looking changes I had applied to my tree, which happened to
affect the order instructions are emitted by GCC causing the bit
twiddling to be done after the clear_pad_bits() call which is supposed
to overwrite the same data through a pointer of different type,
leading to data corruption. A similar failure has been reported by
Vinson Lee on the master branch built with GCC 8.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105052
Tested-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Diffstat (limited to 'src/intel/compiler/test_eu_compact.cpp')
| -rw-r--r-- | src/intel/compiler/test_eu_compact.cpp | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/src/intel/compiler/test_eu_compact.cpp b/src/intel/compiler/test_eu_compact.cpp index 1532e3b9840..f6924abd368 100644 --- a/src/intel/compiler/test_eu_compact.cpp +++ b/src/intel/compiler/test_eu_compact.cpp @@ -149,13 +149,13 @@ test_fuzz_compact_instruction(struct brw_codegen *p, brw_inst src) for (int bit1 = 0; bit1 < 128; bit1++) { brw_inst instr = src; - uint32_t *bits = (uint32_t *)&instr; + uint64_t *bits = instr.data; if (skip_bit(p->devinfo, &src, bit1)) continue; - bits[bit0 / 32] ^= (1 << (bit0 & 31)); - bits[bit1 / 32] ^= (1 << (bit1 & 31)); + bits[bit0 / 64] ^= (1ull << (bit0 & 63)); + bits[bit1 / 64] ^= (1ull << (bit1 & 63)); clear_pad_bits(p->devinfo, &instr); |