[Bug target/40265] New: sh2a compiler ICEs in simplify_subreg, at simplify-rtx.c:4960

["kkojima at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

Newlib build fails during compiling libc/stdlib/ldtoa.c for m2a with

  internal compiler error: in simplify_subreg, at simplify-rtx.c:4960

A reduced testcase is

void
foo (unsigned short *x, unsigned short *y)
{
  unsigned short *p = x;

  *y = 0;
  if (*p++)
    *y = 0x8000;
}

For m2a, movrt insn is defined as

(define_insn "movrt"
  [(set (match_operand:SI 0 "arith_reg_dest" "=r")
        (if_then_else (eq:SI (reg:SI T_REG) (const_int 0))
        (const_int 1)
        (const_int 0)))]
  "TARGET_SH2A"
  "movrt\\t%0"
   [(set_attr "type" "arith")])

and now sh.c:sh_expand_t_scc generates this insn as an scc
instruction.  It seems that it's too complex as an scc insn
and confuses the combine phase.  I'm testing the patch below
which uses another movrt insn with more simple arithmetic
definition

(define_insn "xorsi3_movrt"
  [(set (match_operand:SI 0 "arith_reg_dest" "=r")
        (xor:SI (reg:SI T_REG)
                (const_int 1)))]
  "TARGET_SH2A"
  "movrt\\t%0"
  [(set_attr "type" "arith")])

diff -uprN ORIG/trunk/gcc/config/sh/sh.c trunk/gcc/config/sh/sh.c
--- ORIG/trunk/gcc/config/sh/sh.c       2009-05-25 08:19:47.000000000 +0900
+++ trunk/gcc/config/sh/sh.c    2009-05-27 07:32:14.000000000 +0900
@@ -11085,7 +11085,7 @@ sh_expand_t_scc (rtx operands[])
     emit_insn (gen_movt (result));
   else if (TARGET_SH2A && ((code == EQ && val == 0)
                            || (code == NE && val == 1)))
-    emit_insn (gen_movrt (result));
+    emit_insn (gen_xorsi3_movrt (result));
   else if ((code == EQ && val == 0) || (code == NE && val == 1))
     {
       emit_clobber (result);
diff -uprN ORIG/trunk/gcc/config/sh/sh.md trunk/gcc/config/sh/sh.md
--- ORIG/trunk/gcc/config/sh/sh.md      2009-05-19 10:49:14.000000000 +0900
+++ trunk/gcc/config/sh/sh.md   2009-05-27 07:32:14.000000000 +0900
@@ -9109,16 +9109,6 @@ mov.l\\t1f,r0\\n\\
   "movt        %0"
   [(set_attr "type" "arith")])

-;; complements the T bit and stores the result in a register
-(define_insn "movrt"
-  [(set (match_operand:SI 0 "arith_reg_dest" "=r")
-        (if_then_else (eq:SI (reg:SI T_REG) (const_int 0))
-        (const_int 1)
-        (const_int 0)))]
-  "TARGET_SH2A"
-  "movrt\\t%0"
-   [(set_attr "type" "arith")])
-
 (define_expand "cstore4_media"
   [(set (match_operand:SI 0 "register_operand" "=r")
        (match_operator:SI 1 "sh_float_comparison_operator"


-- 
           Summary: sh2a compiler ICEs in simplify_subreg, at simplify-
                    rtx.c:4960
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kkojima at gcc dot gnu dot org
GCC target triplet: sh-unkonwn-elf


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40265