[Bugfix] Fix div zero error in rewrite_simplify #8961
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syang-ng
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comaniac,
jroesch,
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yzhliu
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comaniac
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Sep 8, 2021
| # KIND, either express or implied. See the License for the | ||
| # specific language governing permissions and limitations | ||
| # under the License. | ||
| import py |
src/arith/rewrite_simplify.cc
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Comment on lines
477
to
478
| // If divisor is equal to zero | ||
| ICHECK(c2val != 0) << "division by zero"; |
Contributor
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nit: The check itself is clear enough so we probably don't need the comment.
Suggested change
| // If divisor is equal to zero | |
| ICHECK(c2val != 0) << "division by zero"; | |
| ICHECK(c2val != 0) << "division by zero"; |
comaniac
approved these changes
Sep 9, 2021
Hzfengsy
approved these changes
Sep 9, 2021
ylc
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to ylc/tvm
that referenced
this pull request
Sep 29, 2021
* fix div zero error in rewrite_simplify * update the style to fix ci error * remove useless code and comment
ylc
pushed a commit
to ylc/tvm
that referenced
this pull request
Jan 13, 2022
* fix div zero error in rewrite_simplify * update the style to fix ci error * remove useless code and comment
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Bug Description
I found there will be a segfault when we try to use
rewrite_simplifyto simplify div expr whose dividend and divisor areRampandBroadcastrespectively.Here is the code to trigger the segmentation fault error.
(tvm-build) ➜ ~ python test_div_zero.py [1] 44116 floating point exception (core dumped) python test_div_zero.pyBug Analysis
The root cause of this bug is that two numbers are divided directly in src/arith/rewrite_simplify.cc, Line 477.
Thus, I add a zero check in
src/arith/rewrite_simplify.ccto prevent division by 0 in this commit. I also add a test case intests/python/unittest/test_arith_rewrite_simplify.pyto cover this problem.