On Thu, Apr 2, 2020 at 5:36 AM bule <bu...@huawei.com> wrote:
>
> Hello,
>
> An Internal Compiler Error(ICE) is found in ipa-sra optimization pass when it
> handle the argument of internal call svst3 for SVE.
>
> The problem comes from
> gcc/testsuite/gcc.target/aarch64/sve/acle/asm/st2_bf16.c in the test suit,
> which can be reduced to flowing code:
>
> #include <arm_sve.h>
> #include<arm_bf16.h>
> void st2_bf16_base (svbfloat16x3_t z1, svbool_t p0, bfloat16_t *x0, intptr_t
> x1) {
> svst3 (p0, x0, z1);
> }
>
> Compiled with -march=armv8.2-a+sve -msve-vector-bits=256 -O2, it will result
> in a segment fault in IPA-SRA:
>
> > [bule@localhost gcc10_fail]$ gcc st2_bf16.i -o st2_bf16.s -S
> > -march=armv8.2-a+sve -msve-vector-bits=256 -O2
> > during IPA pass: sra
> > st2_bf16.c: In function ‘st2_bf16_base’:
> > st2_bf16.c:10:1: internal compiler error: Segmentation fault
> > ...... /* omit some stack info here. */ ......
> > 0xa34f68 call_summary<isra_call_summary*>::get_create(cgraph_edge*)
> > ../.././gcc/symbol-summary.h:642
> > 0xa34f68 record_nonregister_call_use
> > ../.././gcc/ipa-sra.c:1613
> > 0xa34f68 scan_expr_access
> > ../.././gcc/ipa-sra.c:1781
> > ...... /* omit some stack info here. */ ......
> > Please submit a full bug report,
> > with preprocessed source if appropriate.
> > Please include the complete backtrace with any bug report.
>
> Details can be found in PR 94398.
> Similar problem can be found in svst2、svst4 and other functions of this kind.
>
> This problem is cause by "record_nonregister_call_use" function trying to
> access the call graph edge of an internal call, .MASK_STORE_LANE, which is a
> NULL pointer.
>
> The reason of stepping into "record_nonregister_call_use" function is that
> the upper level function "scan_expr_access" considered the "svbfloat16x3_t z1"
> argument as a valid candidate for further optimization.
>
> A simple solution here is to disqualify the candidate at "scan_expr_access"
> level when the call graph edge is null, which indicates the call is either an
> internal call or a call with no references. For both case, the further
> optimization process should stop before it reference a NULL pointer.
>
> A proposed patch is attached.
>
> Any suggestions?
I think internal calls should be handled like asms which means, lookig
at the source a bit,
instead of ISRA_CTX_ARG pass ISRA_CTX_LOAD to scan_expr_access.
Martin?
Richard.
>
> Thanks,
> Bu Le
