Diff for /wikisrc/users/maya/vax-gcc.mdwn between versions 1.6 and 1.12

version 1.6, 2019/08/29 21:19:09 version 1.12, 2019/09/15 12:56:38
Line 1 Line 1
 # Various GCC/vax issues and invesigation #  # Various GCC/vax issues and invesigation #
   
 ## libgomp crash with -O2 ##  [WIP tree](gcc-mirror/)
   
   ## libgomp crash with -O2 [#58901](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58901) ##
 Repro:  Repro:
   
     #!/bin/sh      #!/bin/sh
Line 22  NetBSD avoids it with a [local diff](htt Line 24  NetBSD avoids it with a [local diff](htt
 It looks like a real bug in vax_legitimate_address_p not handling some addressing modes.    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.  The code to handle offset(reg)[index] might be off: it doesn't like if neither xfoo0, xfoo1 are constant.
   
   
   ## change_address_1, at emit-rtl.c:2286 [#85152](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85152) ##
   
   Repro:
   
       #!/bin/sh
   
       cat << EOF > oacc.i
       void fn2();
       unsigned a;
       int fn1() {
         int b = a >> 16;
         if (b)
           fn2();
       }
       EOF
       vax--netbsdelf-gcc -O2 -c oacc.i
   
 ## unrecognizable insn with any optimization ##  ## unrecognizable insn with any optimization ##
   
 Repro:  Repro:
Line 49  Repro: Line 69  Repro:
     EOF      EOF
     vax--netbsdelf-g++ -O2 -c decl.ii      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
       
   
   This is in VAX-specific code. We need to figure out what instruction pattern this is, that we're missing.
   
   <!--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
   
   [riscv seemed to share the issue](https://github.com/riscv/riscv-binutils-gdb/issues/76) and had fixed it.
   
   ## review comments ##
   
   Jeff Law [provided some feedback](https://gcc.gnu.org/ml/gcc/2019-04/msg00281.html). More of it should be addressed.

Removed from v.1.6  
changed lines
  Added in v.1.12


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