https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94873
Bug ID: 94873 Summary: [8/9/10 Regression] wrong code with -O -fno-merge-constants -fno-split-wide-types -fno-tree-fre Product: gcc Version: 10.0 Status: UNCONFIRMED Keywords: wrong-code Severity: normal Priority: P3 Component: rtl-optimization Assignee: unassigned at gcc dot gnu.org Reporter: zsojka at seznam dot cz Target Milestone: --- Host: x86_64-pc-linux-gnu Target: aarch64-unknown-linux-gnu Created attachment 48416 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48416&action=edit reduced testcase Output: $ aarch64-unknown-linux-gnu-gcc -O -fno-merge-constants -fno-split-wide-types -fno-tree-fre testcase.c -static $ ./a.out `�+%��@� The generated code passes wrong data as the "format" argument; I wasn't able to reproduce this without using __builtin_printf() quickly. ... and w1, w1, 255 //, MEM[(volatile unsigned char *)&x] adrp x0, .LANCHOR0 // tmp98, add x0, x0, :lo12:.LANCHOR0 //, tmp98, bl printf // ... .set .LANCHOR0,. + 0 .LC0: .xword -846514461162629792 .xword 0 .LC1: .string "%02x" ... $ aarch64-unknown-linux-gnu-gcc -v Using built-in specs. COLLECT_GCC=/repo/gcc-trunk/binary-latest-aarch64/bin/aarch64-unknown-linux-gnu-gcc COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-r10-8064-20200430095601-g31e6f829336-checking-yes-rtl-df-extra-aarch64/bin/../libexec/gcc/aarch64-unknown-linux-gnu/10.0.1/lto-wrapper Target: aarch64-unknown-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 --with-sysroot=/usr/aarch64-unknown-linux-gnu --build=x86_64-pc-linux-gnu --host=x86_64-pc-linux-gnu --target=aarch64-unknown-linux-gnu --with-ld=/usr/bin/aarch64-unknown-linux-gnu-ld --with-as=/usr/bin/aarch64-unknown-linux-gnu-as --disable-libstdcxx-pch --prefix=/repo/gcc-trunk//binary-trunk-r10-8064-20200430095601-g31e6f829336-checking-yes-rtl-df-extra-aarch64 Thread model: posix Supported LTO compression algorithms: zlib zstd gcc version 10.0.1 20200430 (experimental) (GCC)