[Bug c++/60729] Compiler failure for combination of -ftrapv and -O3: compiler error: in prepare_cmp_insn

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60729

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2014-04-01
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  The issue is that we vectorize the abs() but fail to provide
a negv_optab for V2DFmode and the fallback expansion fails as well
(this path isn't able to handle the vector case at all).

Issue with expand_abs_nojump which uses absv_optab for FP modes.

Index: gcc/optabs.c
===================================================================
--- gcc/optabs.c        (revision 208988)
+++ gcc/optabs.c        (working copy)
@@ -3384,7 +3384,8 @@ expand_abs_nojump (enum machine_mode mod
 {
   rtx temp;

-  if (! flag_trapv)
+  if (GET_MODE_CLASS (mode) != MODE_INT
+      || ! flag_trapv)
     result_unsignedp = 1;

   /* First try to do it with a special abs instruction.  */
@@ -3407,7 +3408,8 @@ expand_abs_nojump (enum machine_mode mod
     {
       rtx last = get_last_insn ();

-      temp = expand_unop (mode, neg_optab, op0, NULL_RTX, 0);
+      temp = expand_unop (mode, result_unsignedp ? neg_optab : negv_optab,
+                         op0, NULL_RTX, 0);
       if (temp != 0)
        temp = expand_binop (mode, smax_optab, op0, temp, target, 0,
                             OPTAB_WIDEN);
@@ -3449,7 +3451,8 @@ expand_abs (enum machine_mode mode, rtx
 {
   rtx temp, op1;

-  if (! flag_trapv)
+  if (GET_MODE_CLASS (mode) != MODE_INT
+      || ! flag_trapv)
     result_unsignedp = 1;

   temp = expand_abs_nojump (mode, op0, target, result_unsignedp);