[Bug target/78148] New: [7 Regression] r241649 causes -fcompare-debug failure on ppc64le

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78148

            Bug ID: 78148
           Summary: [7 Regression] r241649 causes -fcompare-debug failure
                    on ppc64le
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: trippels at gcc dot gnu.org
                CC: ktkachov at gcc dot gnu.org, segher at gcc dot gnu.org
  Target Milestone: ---
              Host: powerpc64le-unknown-linux-gnu
            Target: powerpc64le-unknown-linux-gnu
             Build: powerpc64le-unknown-linux-gnu

Since r241649:

commit 3d3e04acc6a8f7545d2c589319162967fb7f763a
Author: ktkachov <ktkachov@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Fri Oct 28 14:18:50 2016 +0000

    GIMPLE store merging pass

I get a -fcompare-debug failure when building the Linux kernel on ppc64le.


trippels@gcc2-power8 linux % cat ipmi_msghandler.i
struct ipmi_system_interface_addr {
  int addr_type;
  int channel;
};
struct kernel_ipmi_msg {
  char netfn;
  char cmd;
};
extern void fn2(struct ipmi_system_interface_addr, struct kernel_ipmi_msg);
typedef struct ipmi_smi *ipmi_smi_t;
struct ipmi_channel {
  char medium;
  char protocol;
} a;
ipmi_smi_t e;
struct ipmi_smi {
  int curr_channel;
  struct ipmi_channel channels[];
} fn1() {
  int b;
  struct kernel_ipmi_msg c;
  struct ipmi_system_interface_addr d;
  d.channel = c.netfn = c.cmd = 0;
  fn2(d, c);
}
void fn3() {
  e->channels[0].medium = e->channels[0].protocol = 0;
  fn1();
}

trippels@gcc2-power8 linux % gcc -fcompare-debug -mno-altivec -mno-vsx -O2 -c
ipmi_msghandler.i
gcc: error: ipmi_msghandler.i: -fcompare-debug failure (length)

--- ipmi_msghandler.gkd 2016-10-28 17:17:23.537929840 +0000
+++ ipmi_msghandler.gk.gkd      2016-10-28 17:17:23.587931015 +0000
@@ -142,7 +142,7 @@
         (mem/f/c:DI (reg/f:DI 9 9 [158]) [ e+0 S8 A64]))
"ipmi_msghandler.i":27# {*movdi_internal64}
      (nil))
 (insn # 0 0 (set (mem:HI (plus:DI (reg/f:DI 9 9 [orig:155 e.0_1 ] [155])
-                (const_int 4 [0x4])) [ MEM[(char *)e.0_1 + 4B]+0 S2 A8])
+                (const_int 4 [0x4])) [ MEM[(char *)e.0_1 + 4B]+0 S2 A32])
         (reg:HI 10 10 [159])) "ipmi_msghandler.i":27# {*movhi_internal}
      (expr_list:REG_DEAD (reg:HI 10 10 [159])
         (expr_list:REG_DEAD (reg/f:DI 9 9 [orig:155 e.0_1 ] [155])