On Wed, Sep 15, 2021 at 05:59:08PM +0000, Qing Zhao wrote:
> > Note, the gcc.dg/i386/auto-init* tests fail also, just don't have time to
> > deal with that right now, just try
> > make check-gcc RUNTESTFLAGS='--target_board=unix\{-m32,-m64\}
> > i386.exp=auto-init*'
>
> It’s strange that the above testing on my local x86 machine with the latest
> gcc had less failure than the following:
>
> [opc@qinzhao-ol8u3-x86 build-boot]$ make check-gcc
> RUNTESTFLAGS='--target_board=unix\{-m32,-m64\} i386.exp=auto-init*' &> log &
> [1] 3885164
> [opc@qinzhao-ol8u3-x86 build-boot]$
> [1]+ Done make check-gcc
> RUNTESTFLAGS='--target_board=unix\{-m32,-m64\} i386.exp=auto-init*' &> log
> [opc@qinzhao-ol8u3-x86 build-boot]$ egrep FAIL gcc/testsuite/gcc/gcc.sum
> FAIL: gcc.target/i386/auto-init-2.c scan-rtl-dump-times expand
> "0xfffffffffefefefe" 2
> FAIL: gcc.target/i386/auto-init-2.c scan-rtl-dump-times expand
> "0xfefefefefefefefe" 3
> FAIL: gcc.target/i386/auto-init-3.c scan-assembler-times pxor\t\\%xmm0,
> \\%xmm0 3
> FAIL: gcc.target/i386/auto-init-4.c scan-rtl-dump-times expand
> "0xfffffffffefefefe" 1
> FAIL: gcc.target/i386/auto-init-4.c scan-rtl-dump-times expand
> "\\[0xfefefefefefefefe\\]" 1
> FAIL: gcc.target/i386/auto-init-4.c scan-rtl-dump-times expand
> "0xfffffffffffffffe\\]\\) repeated x16" 1
> FAIL: gcc.target/i386/auto-init-5.c scan-assembler-times \\.long\t0 14
> FAIL: gcc.target/i386/auto-init-padding-3.c scan-assembler movl\t\\$16,
> FAIL: gcc.target/i386/auto-init-padding-3.c scan-assembler rep stosq
> FAIL: gcc.target/i386/auto-init-padding-7.c scan-assembler-times movq\t\\$0, 2
> FAIL: gcc.target/i386/auto-init-padding-8.c scan-assembler-times movq\t\\$0, 2
> FAIL: gcc.target/i386/auto-init-padding-9.c scan-assembler rep stosq
Testing for many instructions is always very fragile and dependent on exact
compiler flags etc. So, either the test should have a particular
-march=/-mtune= options and ideally also -fno-stack-protector
-fno-stack-clash-protection etc. if they could change the expected matching,
or test it at runtime instead (I know, it is playing with fire, because you
are testing the behavior of UB, but perhaps making the functions that use
the uninitialized vars __attribute__((noipa)) and checking whether the vars
contain the expected values might be ok.
Jakub
