From 385caf8f59214afbd6dd0e8dc827d8a0dc52e786 Mon Sep 17 00:00:00 2001
From: Reini Urban <rurban@cpanel.net>
Date: Thu, 27 Feb 2014 00:54:07 -0600
Subject: [PATCH] [imcc] fixup: optimizer comments

do not be overly excited about optimizer features.
---
 compilers/imcc/optimizer.c | 33 +++++++++++----------------------
 1 file changed, 11 insertions(+), 22 deletions(-)

diff --git a/compilers/imcc/optimizer.c b/compilers/imcc/optimizer.c
index 00bcf79ea8..7cb0a2b4a1 100644
--- a/compilers/imcc/optimizer.c
+++ b/compilers/imcc/optimizer.c
@@ -992,9 +992,7 @@ IMCC_subst_constants(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit),
                 r[2]->type & (VTCONST|VT_CONSTP) &&
                 STREQ(name, ops[i])) {
             found = 4;
-            /*
-             * create instruction e.g. add_i_ic_ic => add_i_i_i
-             */
+            /* create instruction e.g. add_i_ic_ic => add_i_i_i */
             snprintf(op, sizeof (op), "%s_%c_%c_%c", name, tolower((unsigned char)r[0]->set),
                     tolower((unsigned char)r[1]->set), tolower((unsigned char)r[2]->set));
             debug_fmt = "opt %s_x_xc_xc => ";
@@ -1002,9 +1000,7 @@ IMCC_subst_constants(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit),
         }
     }
     for (i = 0; !found && i < N_ELEMENTS(ops2); i++) {
-        /*
-         * abs_i_ic ...
-         */
+        /* abs_i_ic ... */
         if (n == 3) {
             PARROT_ASSERT(r[1]);
             if (r[1]->type & (VTCONST|VT_CONSTP) &&
@@ -1018,9 +1014,7 @@ IMCC_subst_constants(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit),
         }
     }
     for (i = 0; !found && i < N_ELEMENTS(ops3); i++) {
-        /*
-         * eq_xc_xc_labelc ...
-         */
+        /* eq_xc_xc_labelc ... */
         if (n == 4 &&
                 r[0]->type & (VTCONST|VT_CONSTP) &&
                 r[1]->type & (VTCONST|VT_CONSTP)  &&
@@ -1033,9 +1027,7 @@ IMCC_subst_constants(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit),
         }
     }
     for (i = 0; !found && i < N_ELEMENTS(ops4); i++) {
-        /*
-         * if_xc_labelc, unless
-         */
+        /* if_xc_labelc, unless */
         if (n == 3 &&
                 r[0]->type & (VTCONST|VT_CONSTP) &&
                 STREQ(name, ops4[i])) {
@@ -1070,9 +1062,7 @@ IMCC_subst_constants(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit),
      * the return value
      */
     if (found <= 2) {
-        /*
-         * create a branch or delete instruction
-         */
+        /* create a branch or delete instruction */
         if (branched) {
             r[0] = r[found];
             tmp = INS(imcc, unit, "branch", "", r, 1, 0, 0);
@@ -1082,9 +1072,7 @@ IMCC_subst_constants(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit),
         }
     }
     else {
-        /*
-         * create set x, constant
-         */
+        /* create set x, constant */
         char b[128];
         switch (r[0]->set) {
           case 'I':
@@ -1154,9 +1142,9 @@ branch_branch(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
 
             if (r && (r->type & VTADDRESS) && r->first_ins) {
                 Instruction * const next = r->first_ins->next;
-                /*                if (!next ||
-                                  STREQ(next->symregs[0]->name, get_branch_reg(ins)->name))
-                                  break;*/
+                /* if (!next ||
+                       STREQ(next->symregs[0]->name, get_branch_reg(ins)->name))
+                     break; */
                 if (next &&
                         (next->type & IF_goto) &&
                         STREQ(next->opname, "branch") &&
@@ -1608,7 +1596,8 @@ dead_code_remove(ARGMOD(imc_info_t *imcc), ARGMOD(IMC_Unit *unit))
 
 =item C<static int used_once(imc_info_t *imcc, IMC_Unit *unit)>
 
-used_once ... deletes assignments, when LHS is unused
+used_once ... deletes assignments, when LHS is unused.
+Only for pure functional ops. Keep ops with sideeffects even if the LHS is never used.
 
 =cut