[PATCH, rs6000] (v2) enable early debug and disable switch for gimple folding

[Will Schmidt]

Hi, 

[Patch, rs6000] (v2) enable early debug and disable switch for gimple folding
    
Enable debug options related to gimple folding for the rs6000 target.
Adds some output to the existing -mdebug=builtin option
Add a -mgimple-folding=off option to disable the early rs6000 gimple folding.

(V2 updates)
Changed variable name to rs6000_fold_gimple. 
Changed option name to "fold-gimple", so -mfold-gimple and -mno-fold-gimple 
options
both work smoothly.
Whitespace updates as noted per review. I also fixed the (missing) space after
cast for the existing debug code.
    
OK for trunk?
    
Thanks,
-Will
    

[gcc]

        2017-08-09  Will Schmidt  <will_schm...@vnet.ibm.com>

        * config/rs6000/rs6000.c: (rs6000_option_override_internal) Add blurb
        to indicate when early gimple folding has been disabled.
        (rs6000_gimple_fold_builtin): Add debug content.
        (rs6000_invalid_builtin): whitespace.
        (rs6000_expand_builtin): Whitespace.
        * config/rs6000/rs6000.opt: Add option for -mfold-gimple.

diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 1fb9861..f970f9e 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -4180,10 +4180,14 @@ rs6000_option_override_internal (bool global_init_p)
     {
       warning (0, N_("-maltivec=le not allowed for big-endian targets"));
       rs6000_altivec_element_order = 0;
     }
 
+  if (!rs6000_fold_gimple)
+     fprintf (stderr,
+     "gimple folding of rs6000 builtins has been disabled.\n");
+
   /* Add some warnings for VSX.  */
   if (TARGET_VSX)
     {
       const char *msg = NULL;
       if (!TARGET_HARD_FLOAT || !TARGET_SINGLE_FLOAT || !TARGET_DOUBLE_FLOAT)
@@ -16052,11 +16056,11 @@ paired_expand_predicate_builtin (enum insn_code 
icode, tree exp, rtx target)
    appropriate target options being set.  */
 
 static void
 rs6000_invalid_builtin (enum rs6000_builtins fncode)
 {
-  size_t uns_fncode = (size_t)fncode;
+  size_t uns_fncode = (size_t) fncode;
   const char *name = rs6000_builtin_info[uns_fncode].name;
   HOST_WIDE_INT fnmask = rs6000_builtin_info[uns_fncode].mask;
 
   gcc_assert (name != NULL);
   if ((fnmask & RS6000_BTM_CELL) != 0)
@@ -16157,10 +16161,26 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
   gcc_checking_assert (fndecl && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD);
   enum rs6000_builtins fn_code
     = (enum rs6000_builtins) DECL_FUNCTION_CODE (fndecl);
   tree arg0, arg1, lhs;
 
+  size_t uns_fncode = (size_t) fn_code;
+  enum insn_code icode = rs6000_builtin_info[uns_fncode].icode;
+  const char *fn_name1 = rs6000_builtin_info[uns_fncode].name;
+  const char *fn_name2 = ((icode != CODE_FOR_nothing)
+                         ? get_insn_name ((int) icode)
+                         : "nothing");
+
+  if (TARGET_DEBUG_BUILTIN)
+  {
+      fprintf (stderr, "rs6000_gimple_fold_builtin %d %s %s\n",
+              fn_code, fn_name1, fn_name2);
+  }
+
+  if (!rs6000_fold_gimple)
+    return false;
+
   /* Generic solution to prevent gimple folding of code without a LHS.  */
   if (!gimple_call_lhs (stmt))
     return false;
 
   switch (fn_code)
@@ -16516,10 +16536,13 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
        gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
        update_call_from_tree (gsi, res);
        return true;
       }
     default:
+       if (TARGET_DEBUG_BUILTIN)
+         fprintf (stderr, "gimple builtin intrinsic not matched:%d %s %s \n",
+                           fn_code, fn_name1, fn_name2);
       break;
     }
 
   return false;
 }
@@ -16549,11 +16572,11 @@ rs6000_expand_builtin (tree exp, rtx target, rtx 
subtarget ATTRIBUTE_UNUSED,
   if (TARGET_DEBUG_BUILTIN)
     {
       enum insn_code icode = rs6000_builtin_info[uns_fcode].icode;
       const char *name1 = rs6000_builtin_info[uns_fcode].name;
       const char *name2 = ((icode != CODE_FOR_nothing)
-                          ? get_insn_name ((int)icode)
+                          ? get_insn_name ((int) icode)
                           : "nothing");
       const char *name3;
 
       switch (rs6000_builtin_info[uns_fcode].attr & RS6000_BTC_TYPE_MASK)
        {
@@ -16569,11 +16592,11 @@ rs6000_expand_builtin (tree exp, rtx target, rtx 
subtarget ATTRIBUTE_UNUSED,
 
 
       fprintf (stderr,
               "rs6000_expand_builtin, %s (%d), insn = %s (%d), type=%s%s\n",
               (name1) ? name1 : "---", fcode,
-              (name2) ? name2 : "---", (int)icode,
+              (name2) ? name2 : "---", (int) icode,
               name3,
               func_valid_p ? "" : ", not valid");
     }       
 
   if (!func_valid_p)
diff --git a/gcc/config/rs6000/rs6000.opt b/gcc/config/rs6000/rs6000.opt
index e94aa07..65e4724 100644
--- a/gcc/config/rs6000/rs6000.opt
+++ b/gcc/config/rs6000/rs6000.opt
@@ -146,10 +146,14 @@ Generate AltiVec instructions using little-endian element 
order.
 
 maltivec=be
 Target Report RejectNegative Var(rs6000_altivec_element_order, 2)
 Generate AltiVec instructions using big-endian element order.
 
+mfold-gimple
+Target Report Var(rs6000_fold_gimple, 1) Init(1)
+Enable early gimple folding of builtins.
+
 mhard-dfp
 Target Report Mask(DFP) Var(rs6000_isa_flags)
 Use decimal floating point instructions.
 
 mmulhw