[Bug rtl-optimization/55838] [4.6/4.7/4.8 Regression] ICE in extract_insn (unrecognizable insn) with -O -funroll-loops

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55838



--- Comment #10 from H.J. Lu <hjl.tools at gmail dot com> 2013-01-01 23:02:02 
UTC ---

This patch avoids using (const_int 129 [0x81]) as step in QImode:



diff --git a/gcc/loop-iv.c b/gcc/loop-iv.c

index 50b7536..aafaae4 100644

--- a/gcc/loop-iv.c

+++ b/gcc/loop-iv.c

@@ -421,6 +421,8 @@ iv_constant (struct rtx_iv *iv, rtx cst, enum machine_mode

mode)

 static bool

 iv_subreg (struct rtx_iv *iv, enum machine_mode mode)

 {

+  rtx step;

+

   /* If iv is invariant, just calculate the new value.  */

   if (iv->step == const0_rtx

       && !iv->first_special)

@@ -442,13 +444,17 @@ iv_subreg (struct rtx_iv *iv, enum machine_mode mode)

   if (GET_MODE_BITSIZE (mode) > GET_MODE_BITSIZE (iv->mode))

     return false;



+  step = simplify_gen_binary (MULT, iv->extend_mode, iv->step, iv->mult);

+  if (trunc_int_for_mode (INTVAL (step), mode) != INTVAL (step))

+      return false;

+

   iv->extend = IV_UNKNOWN_EXTEND;

   iv->mode = mode;



   iv->base = simplify_gen_binary (PLUS, iv->extend_mode, iv->delta,

                   simplify_gen_binary (MULT, iv->extend_mode,

                                iv->base, iv->mult));

-  iv->step = simplify_gen_binary (MULT, iv->extend_mode, iv->step, iv->mult);

+  iv->step = step;

   iv->mult = const1_rtx;

   iv->delta = const0_rtx;

   iv->first_special = false;