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[Bug rtl-optimization/45137] [4.6 Regression] -g changes the generated code for gcc/sched-vis.c on SH



------- Comment #2 from kkojima at gcc dot gnu dot org  2010-07-30 00:50 -------
With -g, .ira for the above test case has the insns:

(insn 143 141 229 14 (set (reg/f:SI 1 r1 [238])
        (const_int 2046 [0x7fe])) yyy.c:25 176 {movsi_ie}
     (expr_list:REG_EQUAL (const_int 2046 [0x7fe])
        (nil)))

(debug_insn 229 143 144 14 (var_location:SI D#2 (reg/v/f:SI 8 r8 [orig:210 buf
] [210])) -1
     (nil))

(insn 144 229 145 14 (set (reg/f:SI 1 r1 [238])
        (plus:SI (reg/f:SI 1 r1 [238])
            (reg/v/f:SI 8 r8 [orig:210 buf ] [210]))) yyy.c:25 35
{*addsi3_compact}
     (expr_list:REG_EQUAL (plus:SI (reg/v/f:SI 8 r8 [orig:210 buf ] [210])
            (const_int 2046 [0x7fe]))
        (nil)))

(insn 145 144 146 14 (set (reg:QI 2 r2 [240])
        (const_int 0 [0])) yyy.c:25 186 {movqi_i}
     (expr_list:REG_EQUIV (const_int 0 [0])
        (nil)))

(insn 146 145 38 14 (set (mem:QI (reg/f:SI 1 r1 [238]) [0 MEM[(char *)buf_1(D)
+ 2046B]+0 S1 A8])
        (reg:QI 2 r2 [240])) yyy.c:25 186 {movqi_i}
     (expr_list:REG_EQUAL (const_int 0 [0])
        (nil)))

When debug_insn 229 is absent, reload_combine_recognize_pattern
converts them to the insns like

(insn 143 141 145 14 (set (reg:SI 0 r0)
        (const_int 2046 [0x7fe])) xxx.c:25 176 {movsi_ie}
     (expr_list:REG_EQUAL (const_int 2046 [0x7fe])
        (nil)))

(insn 145 143 146 14 (set (reg:QI 2 r2 [240])
        (const_int 0 [0])) xxx.c:25 186 {movqi_i}
     (expr_list:REG_EQUIV (const_int 0 [0])
        (nil)))

(insn 146 145 38 14 (set (mem:QI (plus:SI (reg:SI 0 r0)
                (reg/v/f:SI 8 r8 [orig:210 buf ] [210])) [0 MEM[(char
*)buf_1(D) + 2046B]+0 S1 A8])
        (reg:QI 2 r2 [240])) xxx.c:25 186 {movqi_i}
     (expr_list:REG_EQUAL (const_int 0 [0])
        (nil)))

but this isn't done with debug_insn 229.
It seems that reload_combine_recognize_pattern only looks
prev_nonnote_insn of insn 145 as the candidate of
(set (REGX) (CONST_INT)) insn and the debug_insn confuses
it.  I've confirmed that the patch

--- ORIG/trunk/gcc/postreload.c 2010-07-28 09:38:05.000000000 +0900
+++ trunk/gcc/postreload.c      2010-07-30 08:42:50.000000000 +0900
@@ -1113,12 +1113,20 @@ reload_combine_recognize_pattern (rtx in
       && last_label_ruid < reg_state[regno].use_ruid)
     {
       rtx base = XEXP (src, 1);
-      rtx prev = prev_nonnote_insn (insn);
-      rtx prev_set = prev ? single_set (prev) : NULL_RTX;
+      rtx prev;
+      rtx prev_set;
       rtx index_reg = NULL_RTX;
       rtx reg_sum = NULL_RTX;
       int i;

+      /* Find the previous non-note/dubug insn.  */
+      prev = insn;
+      do {
+       prev = prev_nonnote_insn (prev);
+      } while (prev && DEBUG_INSN_P (prev));
+
+      prev_set = prev ? single_set (prev) : NULL_RTX;
+
       /* Now we need to set INDEX_REG to an index register (denoted as
         REGZ in the illustration above) and REG_SUM to the expression
         register+register that we want to use to substitute uses of REG

fixes the problem.
Perhaps {next,prev}_nonnote_nondebug_insn should be added
to emit-rtl.c and use it here.  Thoughts?


-- 

kkojima at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|-g changes the generated    |[4.6 Regression] -g changes
                   |code for gcc/sched-vis.c on |the generated code for
                   |SH                          |gcc/sched-vis.c on SH


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45137


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