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[Patch]Fix ICE for gcc.dg/noncompile/920507-1.c


Hi there,

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61330. 
There will be an ICE in gcc trunk for targets support section anchor
optimization when compiling this case(like arm and mips). This looks like an
old bug which is exposed by recent patch.

In make_decl_rtl, when you declare register type incorrectly like "register
int *a asm("unknown register");", the compiler will raise an error messge
but doesn't return directly. It will continue to run into the rtx generation
code for general variable declaration and generate a wrong
rtx:(symbol_ref:SI...). So I just remove the else condition which used to be
the rtx generation part for correctly declared register type, and let all
the register type declaration(no matter it declared correct or not) go
through it and generate the same type of rtx:(reg:SI...).

gcc/ChangeLog:

2014-07-29  Tony Wang  tony.wang@arm.com

        * gcc/varasm.c (make_decl_rtl): Remove the else condition
          for properly declared static register variables.

diff --git a/gcc/varasm.c b/gcc/varasm.c index 819ec26..a6fae0c 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -1333,45 +1333,42 @@ make_decl_rtl (tree decl)
               error ("register specified for %q+D isn%'t suitable for data
type",
                decl);
       /* Now handle properly declared static register variables.  */
-      else
-              {
-                int nregs;
+      int nregs;

-                if (DECL_INITIAL (decl) != 0 && TREE_STATIC (decl))
-                  {
-                    DECL_INITIAL (decl) = 0;
-                    error ("global register variable has initial value");
-                  }
-                if (TREE_THIS_VOLATILE (decl))
-                  warning (OPT_Wvolatile_register_var,
-                                   "optimization may eliminate reads and/or
"
-                                   "writes to register variables");
+      if (DECL_INITIAL (decl) != 0 && TREE_STATIC (decl))
+        {
+           DECL_INITIAL (decl) = 0;
+           error ("global register variable has initial value");
+        }
+      if (TREE_THIS_VOLATILE (decl))
+        warning (OPT_Wvolatile_register_var,
+                 "optimization may eliminate reads and/or "
+                      "writes to register variables");

-                /* If the user specified one of the eliminables registers
here,
-                   e.g., FRAME_POINTER_REGNUM, we don't want to get this
variable
-                   confused with that register and be eliminated.  This
usage is
-                   somewhat suspect...  */
+      /* If the user specified one of the eliminables registers here,
+         e.g., FRAME_POINTER_REGNUM, we don't want to get this variable
+         confused with that register and be eliminated.  This usage is
+         somewhat suspect...  */

-                SET_DECL_RTL (decl, gen_rtx_raw_REG (mode, reg_number));
-                ORIGINAL_REGNO (DECL_RTL (decl)) = reg_number;
-                REG_USERVAR_P (DECL_RTL (decl)) = 1;
+      SET_DECL_RTL (decl, gen_rtx_raw_REG (mode, reg_number));
+      ORIGINAL_REGNO (DECL_RTL (decl)) = reg_number;
+      REG_USERVAR_P (DECL_RTL (decl)) = 1;

-                if (TREE_STATIC (decl))
-                  {
-                    /* Make this register global, so not usable for
anything
-                              else.  */
+      if (TREE_STATIC (decl))
+        {
+          /* Make this register global, so not usable for anything
+             else.  */
#ifdef ASM_DECLARE_REGISTER_GLOBAL
-                    name = IDENTIFIER_POINTER (DECL_NAME (decl));
-                    ASM_DECLARE_REGISTER_GLOBAL (asm_out_file, decl,
reg_number, name);
+          name = IDENTIFIER_POINTER (DECL_NAME (decl));
+          ASM_DECLARE_REGISTER_GLOBAL (asm_out_file, decl, reg_number, 
+ name);
#endif
-                    nregs = hard_regno_nregs[reg_number][mode];
-                    while (nregs > 0)
-                              globalize_reg (decl, reg_number + --nregs);
-                  }
+          nregs = hard_regno_nregs[reg_number][mode];
+          while (nregs > 0)
+            globalize_reg (decl, reg_number + --nregs);
+        }

-                /* As a register variable, it has no section.  */
-                return;
-              }
+      /* As a register variable, it has no section.  */
+      return;
     }
   /* Now handle ordinary static variables and functions (in memory).
      Also handle vars declared register invalidly.  */

BR,
Tony

Attachment: 920507.diff
Description: Binary data


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