https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116044
--- Comment #1 from Thomas Schwinge <tschwinge at gcc dot gnu.org> --- Recent commit r15-2199-g34f33ea801563e2eabb348e8d3e9344a91abfd48 "rtl-ssa: Avoid using a stale splay tree root [PR116009]" is causing one regression for '--target=amdgcn-amdhsa' (tested '-march=gfx908'): PASS: g++.dg/torture/pr81987.C -O0 (test for excess errors) PASS: g++.dg/torture/pr81987.C -O1 (test for excess errors) PASS: g++.dg/torture/pr81987.C -O2 (test for excess errors) PASS: g++.dg/torture/pr81987.C -O3 -g (test for excess errors) {+FAIL: g++.dg/torture/pr81987.C -Os (internal compiler error: in merge_clobber_groups, at rtl-ssa/accesses.cc:764)+} [-PASS:-]{+FAIL:+} g++.dg/torture/pr81987.C -Os (test for excess errors) during RTL pass: late_combine [...]/source-gcc/gcc/testsuite/g++.dg/torture/pr81987.C: In function 'void foo()': [...]/source-gcc/gcc/testsuite/g++.dg/torture/pr81987.C:61:1: internal compiler error: in merge_clobber_groups, at rtl-ssa/accesses.cc:764 0x2406235 internal_error(char const*, ...) [...]/source-gcc/gcc/diagnostic-global-context.cc:491 0xb80382 fancy_abort(char const*, int, char const*) [...]/source-gcc/gcc/diagnostic.cc:1725 0xb68dc1 rtl_ssa::function_info::merge_clobber_groups(rtl_ssa::clobber_info*, rtl_ssa::clobber_info*, rtl_ssa::def_info*) [...]/source-gcc/gcc/rtl-ssa/accesses.cc:764 0x226d49e rtl_ssa::function_info::remove_def(rtl_ssa::def_info*) [...]/source-gcc/gcc/rtl-ssa/accesses.cc:1036 0x2274463 rtl_ssa::function_info::change_insns(array_slice<rtl_ssa::insn_change*>) [...]/source-gcc/gcc/rtl-ssa/changes.cc:852 0x222672a run [...]/source-gcc/gcc/late-combine.cc:452 0x222672a combine_into_uses [...]/source-gcc/gcc/late-combine.cc:683 0x2226c1d execute [...]/source-gcc/gcc/late-combine.cc:711 0x2226c1d execute [...]/source-gcc/gcc/late-combine.cc:760