https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88995
--- Comment #1 from Sunil Pandey <skpgkp1 at gmail dot com> --- Created attachment 45513 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45513&action=edit small reproducer. Pass with GCC 8.2.0 but fail with mainline GCC. GCC 8.2.0: ---------- $ gcc -O2 -fPIC -g -feliminate-unused-debug-types -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=32 -Wformat -Wformat-security -Wl,-z,now,-z,relro,-z,max-page-size=0x1000,-z,separate-code -Wno-error -ftree-vectorize -ftree-slp-vectorize -march=westmere -mtune=haswell -fasynchronous-unwind-tables -fno-omit-frame-pointer -O3 -falign-functions=32 -fno-math-errno -fno-semantic-interposition -fno-trapping-math -Werror=return-type -Wuninitialized -Winit-self -Wmaybe-uninitialized -O2 -g -fvisibility=default -fopenmp -std=gnu++11 -S x.ii $ echo $? 0 GCC Mainline: ============= $ gcc -O2 -fPIC -g -feliminate-unused-debug-types -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=32 -Wformat -Wformat-security -Wl,-z,now,-z,relro,-z,max-page-size=0x1000,-z,separate-code -Wno-error -ftree-vectorize -ftree-slp-vectorize -march=westmere -mtune=haswell -fasynchronous-unwind-tables -fno-omit-frame-pointer -O3 -falign-functions=32 -fno-math-errno -fno-semantic-interposition -fno-trapping-math -Werror=return-type -Wuninitialized -Winit-self -Wmaybe-uninitialized -O2 -g -fvisibility=default -fopenmp -std=gnu++11 -S x.ii -w x.ii:711: internal compiler error: in lookup_template_class_1, at cp/pt.c:9471 711 | namespace cpu { using namespace mkldnn::impl::status; using namespace mkldnn::impl::memory_format; using namespace mkldnn::impl::data_type; using namespace mkldnn::impl::utils; using math::saturate; templ | 0x64160c lookup_template_class_1 ../../gcc-main.42P5/gcc/cp/pt.c:9471 0x64160c lookup_template_class(tree_node*, tree_node*, tree_node*, tree_node*, int, int) ../../gcc-main.42P5/gcc/cp/pt.c:9683 0x9eec7c tsubst_aggr_type ../../gcc-main.42P5/gcc/cp/pt.c:12686 0x9d6404 tsubst_copy ../../gcc-main.42P5/gcc/cp/pt.c:15462 0x9d8ff3 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool, bool) ../../gcc-main.42P5/gcc/cp/pt.c:19060 0x9cf937 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc-main.42P5/gcc/cp/pt.c:17756 0x9dfc01 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc-main.42P5/gcc/cp/pt.c:16847 0x9dfc01 tsubst_decl ../../gcc-main.42P5/gcc/cp/pt.c:13779 0x9d78eb tsubst_copy ../../gcc-main.42P5/gcc/cp/pt.c:15507 0x9d8988 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool, bool) ../../gcc-main.42P5/gcc/cp/pt.c:19259 0x9d8de4 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool, bool) ../../gcc-main.42P5/gcc/cp/pt.c:18169 0x9d8599 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool, bool) ../../gcc-main.42P5/gcc/cp/pt.c:18348 0x9d981f tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool, bool) ../../gcc-main.42P5/gcc/cp/pt.c:18381 0x9d85e4 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool, bool) ../../gcc-main.42P5/gcc/cp/pt.c:18349 0x9d8599 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool, bool) ../../gcc-main.42P5/gcc/cp/pt.c:18348 0x9cf937 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc-main.42P5/gcc/cp/pt.c:17756 0x9d4ec2 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc-main.42P5/gcc/cp/pt.c:15346 0x9d4ec2 tsubst_init ../../gcc-main.42P5/gcc/cp/pt.c:15350 0x9d3f3e tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc-main.42P5/gcc/cp/pt.c:16997 0x9d124e tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc-main.42P5/gcc/cp/pt.c:16862 Please submit a full bug report, with preprocessed source if appropriate. Please include the complete backtrace with any bug report. See <https://gcc.gnu.org/bugs/> for instructions.