Hi Aldy! On Thu, 2021-10-14 16:25:48 +0200, Aldy Hernandez via Gcc-patches wrote: > The new backward threader makes some of the --param knobs used to > control it questionable at best or no longer applicable at worst. > > The fsm-maximum-phi-arguments param is unused and can be removed. > > The max-fsm-thread-length param is block based which is a bit redundant, > since we already restrict paths based on instruction estimates. > > The max-fsm-thread-paths restricts the total number of threadable paths > in a function. We probably don't need this. Besides, the forward > threader has no such restriction. > > OK pending tests? This causes a regression for me. I'm auto-building lots of GCC cross-compilers and use these to cross-build the Linux kernel. Using binutils/gas/gcc configured for --target=sh-linux (actual configuration for GCC is this: .../gcc/configure --target=sh-linux --enable-werror-always \ --enable-languages=all --disable-gcov \ --disable-shared --disable-threads \ --without-headers \ --prefix=/var/lib/laminar/run/gcc-sh-linux/13/toolchain-install ) Then, building Linux for a good number of default configurations for ARCH=sh and ARCH=arm, GCC will just loop: $ make ARCH=sh distclean $ cp arch/sh/configs/r7780mp_defconfig .config $ make V=1 ARCH=sh CROSS_COMPILE=sh-linux- oldconfig < /dev/null $ make V=1 ARCH=sh CROSS_COMPILE=sh-linux- prepare $ make V=1 ARCH=sh CROSS_COMPILE=sh-linux- all [...] sh-linux-gcc -Wp,-MMD,drivers/ata/.libata-core.o.d -nostdinc -isystem /tmp/testbed/install/lib/gcc/sh-linux/12.0.0/include -I./arch/sh/include -I./arch/sh/include/generated -I./include -I./arch/sh/include/uapi -I./arch/sh/include/generated/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/compiler-version.h -include ./include/linux/kconfig.h -include ./include/linux/compiler_types.h -D__KERNEL__ -m4 -m4-nofpu -m4a -m4a-nofpu -ml -mno-fdpic -Wa,-isa=sh4a-up -ffreestanding -I ./arch/sh/include/cpu-sh4a -I ./arch/sh/include/cpu-sh4 -I ./arch/sh/include/cpu-common -I ./arch/sh/include/mach-highlander -I ./arch/sh/include/mach-common -fmacro-prefix-map=./= -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -fshort-wchar -fno-PIE -Werror=implicit-function-declaration -Werror=implicit-int -Werror=return-type -Wno-format-security -std=gnu89 -pipe -m4 -m4-nofpu -m4a -m4a-nofpu -ml -mno-fdpic -Wa,-isa=sh4a-up -ffreestanding -I ./arch/sh/include/cpu-sh4a -I ./arch/sh/include/cpu-sh4 -I ./arch/sh/include/cpu-common -I ./arch/sh/include/mach-highlander -I ./arch/sh/include/mach-common -fno-delete-null-pointer-checks -Wno-frame-address -Wno-format-truncation -Wno-format-overflow -Wno-address-of-packed-member -O2 -fno-allow-store-data-races -Wframe-larger-than=1024 -fstack-protector-strong -Wimplicit-fallthrough=5 -Wno-main -Wno-unused-but-set-variable -Wno-unused-const-variable -fomit-frame-pointer -ftrivial-auto-var-init=zero -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang -fno-stack-clash-protection -g -Wdeclaration-after-statement -Wvla -Wno-pointer-sign -Wno-stringop-truncation -Wno-zero-length-bounds -Wno-array-bounds -Wno-stringop-overflow -Wno-restrict -Wno-maybe-uninitialized -fno-strict-overflow -fno-stack-check -fconserve-stack -Werror=date-time -Werror=incompatible-pointer-types -Werror=designated-init -Wno-packed-not-aligned -DKBUILD_MODFILE='"drivers/ata/libata"' -DKBUILD_BASENAME='"libata_core"' -DKBUILD_MODNAME='"libata"' -D__KBUILD_MODNAME=kmod_libata -c -o drivers/ata/libata-core.o drivers/ata/libata-core.c (gdb) bt #0 0x000000000100318e in vec::operator[] (ix=0, this=0x50ee6e0) at ../../gcc/gcc/vec.h:1495 #1 back_jt_path_registry::adjust_paths_after_duplication (this=0x7ffdf8b6e868, curr_path_num=0) at ../../gcc/gcc/tree-ssa-threadupdate.c:2315 #2 0x0000000001003c0d in back_jt_path_registry::duplicate_thread_path (this=0x7ffdf8b6e868, entry=0x7f92651000c0, exit=, region=, n_region=8, current_path_no=0) at ../../gcc/gcc/tree-ssa-threadupdate.c:2546 #3 0x00000000010051e4 in back_jt_path_registry::update_cfg (this=0x7ffdf8b6e868) at ../../gcc/gcc/tree-ssa-threadupdate.c:2656 #4 0x0000000001003ecc in jt_path_registry::thread_through_all_blocks (this=0x7ffdf8b6e868, peel_loop_headers=) at ../../gcc/gcc/tree-ssa-threadupdate.c:2604 #5 0x0000000000ffb5a7 in back_threader_registry::thread_through_all_blocks (may_peel_loop_headers=true, this=0x7ffdf8b6e868) at ../../gcc/gcc/tree-ssa-threadbackward.c:556 #6 back_threader::thread_through_all_blocks (may_peel_loop_headers=true, this=0x7ffdf8b6e860) at ../../gcc/gcc/tree-ssa-threadbackward.c:501 #7 (anonymous namespace)::try_thread_blocks (fun=fun@entry=0x7f926eb389c0) at ../../gcc/gcc/tree-ssa-threadbackward.c:946 #8 0x0000000000ffb5eb in (anonymous namespace)::pass_thread_jumps::execute (this=, fun=0x7f926eb389c0) at ../../gcc/gcc/tree-ssa-threadbackward.c:954 #9 0x0000000000cfcdf8 in execute_one_pass (pass=0x2a980d0) at ../../gcc/gcc/passes.c:2567 #10 0x0000000000cfd770 in execute_pass_list_1 (pass=0x2a980d0) at ../../gcc/gcc/passes.c:2656 #11 0x0000000000cfd782 in execute_pass_list_1 (pass=0x2a95ab0) at ../../gcc/gcc/passes.c:2657 #12 0x0000000000cfd7a9 in execute_pass_list (fn=0x7f926eb389c0, pass=) at ../../gcc/gcc/passes.c:2667 #13 0x00000000009719c6 in cgraph_node::expand (this=0x7f926eb59550) at ../../gcc/gcc/context.h:48 #14 cgraph_node::expand (this=0x7f926eb59550) at ../../gcc/gcc/cgraphunit.c:1781 #15 0x0000000000972eb8 in expand_all_functions () at ../../gcc/gcc/cgraphunit.c:1992 #16 symbol_table::compile (this=0x7f9271f36000) at ../../gcc/gcc/cgraphunit.c:2356 #17 0x0000000000975948 in symbol_table::compile (this=0x7f9271f36000) at ../../gcc/gcc/cgraphunit.c:2269 #18 symbol_table::finalize_compilation_unit (this=0x7f9271f36000) at ../../gcc/gcc/cgraphunit.c:2537 #19 0x0000000000de87a6 in compile_file () at ../../gcc/gcc/toplev.c:477 #20 0x00000000007ca783 in do_compile (no_backend=false) at ../../gcc/gcc/toplev.c:2197 #21 toplev::main (this=this@entry=0x7ffdf8b6f00e, argc=, argc@entry=128, argv=, argv@entry=0x7ffdf8b6f118) at ../../gcc/gcc/toplev.c:2346 #22 0x00000000007cc74f in main (argc=128, argv=0x7ffdf8b6f118) at ../../gcc/gcc/main.c:39 Shall I open a PR for it? MfG, JBG --