https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85859
Bug ID: 85859 Summary: [6/7/8/9 Regression] wrong code with -fno-isolate-erroneous-paths-dereference Product: gcc Version: 9.0 Status: UNCONFIRMED Keywords: wrong-code Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: zsojka at seznam dot cz Target Milestone: --- Host: x86_64-pc-linux-gnu Target: x86_64-pc-linux-gnu Created attachment 44156 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44156&action=edit reduced testcase Output: $ x86_64-pc-linux-gnu-gcc -O2 -fno-dce -fno-isolate-erroneous-paths-dereference -fno-tree-dce -fno-tree-vrp testcase.c testcase.c: In function 'foo': testcase.c:6:5: warning: division by zero [-Wdiv-by-zero] f %= 0; ^~ $ ./a.out Floating point exception The division by zero should not be executed. $ x86_64-pc-linux-gnu-gcc -v Using built-in specs. COLLECT_GCC=/repo/gcc-trunk/binary-latest-amd64/bin/x86_64-pc-linux-gnu-gcc COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-260408-checking-yes-rtl-df-extra-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/9.0.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++ --enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra --with-cloog --with-ppl --with-isl --build=x86_64-pc-linux-gnu --host=x86_64-pc-linux-gnu --target=x86_64-pc-linux-gnu --with-ld=/usr/bin/x86_64-pc-linux-gnu-ld --with-as=/usr/bin/x86_64-pc-linux-gnu-as --disable-libstdcxx-pch --prefix=/repo/gcc-trunk//binary-trunk-260408-checking-yes-rtl-df-extra-amd64 Thread model: posix gcc version 9.0.0 20180520 (experimental) (GCC)