https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77813
Bug ID: 77813
Summary: __TMC_END__ - __TMC_LIST__ == 0
Product: gcc
Version: 7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libgcc
Assignee: unassigned at gcc dot gnu.org
Reporter: glisse at gcc dot gnu.org
Target Milestone: ---
Target: powerpc64le-unknown-linux-gnu
In crtstuff.c, function deregister_tm_clones contains this code:
if (__TMC_END__ - __TMC_LIST__ == 0)
this currently gives, in the original dump
if (((unsigned long) &__TMC_END__ + 7) - (unsigned long) &__TMC_LIST__ <= 14)
I was testing an optimization that allows us to get instead
if ((long int) &__TMC_END__ == (long int) &__TMC_LIST__)
During forwprop, the match.pd pattern (cmp (convert1?@2 addr@0) (convert2?
addr@1)) applies and we fold this to 0. In the libitm testsuite, most runtime
tests then segfault.
It seems that either the optimization to compare addresses is too eager, or the
code in crtstuff.c doesn't mark the variables appropriately...
