--- wikisrc/users/maya/vax-gcc.mdwn 2019/08/29 13:01:34 1.3 +++ wikisrc/users/maya/vax-gcc.mdwn 2019/08/30 04:49:49 1.9 @@ -1,6 +1,8 @@ # Various GCC/vax issues and invesigation # -# libgomp crash with -O2 # +[WIP tree](gcc-mirror/) + +## libgomp crash with -O2 ## Repro: #!/bin/sh @@ -18,6 +20,67 @@ Repro: Asserts at emit-rtl.c:2310 gcc_assert (memory_address_addr_space_p (mode, addr, as)); -NetBSD avoids it with a [local diff](5f534f20bc66738c05c442a8f20088f55335b653/external/gpl3/gcc/dist/libgcc/gthr-posix.h#L418) to reload.c/dse.c. +NetBSD avoids it with a [local diff](https://github.com/NetBSD/src/commit/e437e96750193b86d0464965661f616e011056fa) to reload.c/dse.c. It looks like a real bug in vax_legitimate_address_p not handling some addressing modes. The code to handle offset(reg)[index] might be off: it doesn't like if neither xfoo0, xfoo1 are constant. + +## unrecognizable insn with any optimization ## + +Repro: + + #!/bin/sh + + cat << EOF > decl.ii + struct a { + long long *b() const; + }; + template class d : a { + public: + template d(e); + long long f() const; + }; + template long long d::f() const { + int g; + return b()[g]; + } + int h; + bool i() { + d j(h); + return j.f(); + } + EOF + vax--netbsdelf-g++ -O2 -c decl.ii + +This errors out with: + + $ env PATH=$PWD:$PATH ./xgcc -fno-use-linker-plugin -c -O2 ~/oacc/decl.ii -fno-tree-vectorize + /home/fly/oacc/decl.ii: In function 'bool i()': + /home/fly/oacc/decl.ii:17:1: error: unrecognizable insn: + 17 | } + | ^ + (insn 13 12 14 2 (set (reg:SI 33) + (subreg:SI (mem:DI (plus:SI (mult:SI (reg/v:SI 24 [ g ]) + (const_int 8 [0x8])) + (reg/f:SI 23 [ _6 ])) [1 *_10+0 S8 A32]) 4)) "/home/fly/oacc/decl.ii":16:14 -1 + (nil)) + during RTL pass: vregs + /home/fly/oacc/decl.ii:17:1: internal compiler error: in extract_insn, at recog.c:2310 + +Providing a trivial scheduling will avoid subregs of mem. +However, this doesn't work for us. Our crash and mem subregs happen at a too early pass, most likely. + +## DWARF ## + + flag_dwarf2_cfi_asm = 0; + +is kind of a big deal. We should probably get rid of it, but [binutils hates that.](https://github.com/NetBSD/src/commit/1df57dce3744cf4743358b098728a0658b80b8fb) + + ld: warning: dynamic relocation to `?' in readonly section `.eh_frame' + ld: warning: dynamic relocation to `?' in readonly section `.eh_frame' + ld: warning: creating a DT_TEXTREL in a shared object + ld: .eh_frame_hdr refers to overlapping FDEs + ld: final link failed: bad value + +## review comments ## + +Jeff Law [provided some feedback](https://gcc.gnu.org/ml/gcc/2019-04/msg00281.html). More of it should be addressed.