[Bug rtl-optimization/79286] [7 Regression] ira and lra wrong code at -O2 and -Os on i686-linux

[bernd.edlinger at hotmail dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79286

Bernd Edlinger <bernd.edlinger at hotmail dot de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bernd.edlinger at hotmail dot de

--- Comment #12 from Bernd Edlinger <bernd.edlinger at hotmail dot de> ---
Hi Jeff,

it looks like it is possible that may_trap_p returns
always wrong information if -m32 -fPIC is used.

What do you think about this?

Index: gcc/rtlanal.c
===================================================================
--- gcc/rtlanal.c       (revision 245714)
+++ gcc/rtlanal.c       (working copy)
@@ -645,8 +645,23 @@
     case PLUS:
       /* An address is assumed not to trap if:
          - it is the pic register plus a constant.  */
-      if (XEXP (x, 0) == pic_offset_table_rtx && CONSTANT_P (XEXP (x, 1)))
-       return 0;
+      if (XEXP (x, 0) == pic_offset_table_rtx
+         && GET_CODE (XEXP (x, 1)) == CONST)
+       {
+         x = XEXP (XEXP (x, 1), 0);
+         if (GET_CODE (x) == UNSPEC
+             && GET_CODE (XVECEXP (x, 0, 0)) == SYMBOL_REF)
+           return rtx_addr_can_trap_p_1(XVECEXP (x, 0, 0),
+                                        offset, size, mode, unaligned_mems);
+         if (GET_CODE (x) == PLUS
+             && GET_CODE (XEXP (x, 0)) == UNSPEC
+             && GET_CODE (XVECEXP (XEXP (x, 0), 0, 0)) == SYMBOL_REF
+             && CONST_INT_P (XEXP (x, 1)))
+           return rtx_addr_can_trap_p_1(XVECEXP (XEXP (x, 0), 0, 0),
+                                        offset + INTVAL (XEXP (x, 1)),
+                                        size, mode, unaligned_mems);
+         return 1;
+       }

       /* - or it is an address that can't trap plus a constant integer.  */
       if (CONST_INT_P (XEXP (x, 1))