Re: [PATCH 1/2] Fix new -Wparentheses warnings encountered during bootstrap

[Patrick Palka <patrick@parcs.ath.cx>]

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On Thu, 31 Mar 2016, Patrick Palka wrote:

> This patch fixes the new -Wparentheses warnings (implemented by the
> subsequent patch) that are encountered during bootstrap:
> 
> /home/patrick/code/gcc/gcc/omp-low.c: In function ‘void scan_sharing_clauses(tree, omp_context*, bool)’:
> /home/patrick/code/gcc/gcc/omp-low.c:2381:6: error: suggest explicit braces to avoid ambiguous ‘else’ [-Werror=parentheses]
>    if (scan_array_reductions)
>       ^
> /home/patrick/code/gcc/gcc/gimplify.c: In function ‘gimple* gimplify_omp_ordered(tree, gimple_seq)’:
> /home/patrick/code/gcc/gcc/gimplify.c:9880:6: error: suggest explicit braces to avoid ambiguous ‘else’ [-Werror=parentheses]
>    if (gimplify_omp_ctxp)
>       ^
> In file included from /home/patrick/code/gcc/gcc/cp/optimize.c:25:0:
> /home/patrick/code/gcc/gcc/cp/optimize.c: In function ‘void populate_clone_array(tree, tree_node**)’:
> /home/patrick/code/gcc/gcc/cp/cp-tree.h:2529:6: error: suggest explicit braces to avoid ambiguous ‘else’ [-Werror=parentheses]
>    if (TREE_CODE (FN) == FUNCTION_DECL   \
>       ^
> /home/patrick/code/gcc/gcc/cp/optimize.c:222:3: note: in expansion of macro ‘FOR_EACH_CLONE’
>    FOR_EACH_CLONE (clone, fn)
>    ^~~~~~~~~~~~~~
> /home/patrick/code/gcc/gcc/fortran/openmp.c: In function ‘gfc_omp_udr* gfc_find_omp_udr(gfc_namespace*, const char*, gfc_typespec*)’:
> /home/patrick/code/gcc/gcc/fortran/openmp.c:177:10: error: suggest explicit braces to avoid ambiguous ‘else’ [-Werror=parentheses]
>        if (st != NULL)
>           ^
> 
> In each case I think the warning is harmless since the indentation of
> the code in question corresponds to how the "else" is actually parsed
> so I fixed each case simply by enclosing the entire body of the outer
> "if" in braces.
> 
> The FOR_EACH_CLONE change resolves the cp/optimize.c warning.  It
> adjusts the layout of the macro from
> 
>   if (p)
>     for (...)
> 
> to
> 
>   if (!p)
>     ;
>   else for (...)
> 
> so that an "else" encountered in the body of the for-statement can no
> longer possibly bind to the outer "if (p)" conditional.
> 
> Is this OK to commit after bootstrap + regtesting?
> 
> gcc/cp/ChangeLog:
> 
> 	PR c/70436
> 	* cp-tree.h (FOR_EACH_CLONE): Restructure macro to avoid
> 	potentially generating a future -Wparentheses warning in its
> 	callers.
> 
> gcc/fortran/ChangeLog:
> 
> 	PR c/70436
> 	* openmp.c (gfc_find_omp_udr): Add explicit braces to resolve a
> 	future -Wparentheses warning.
> 
> gcc/ChangeLog:
> 
> 	PR c/70436
> 	* gimplify.c (gimplify_omp_ordered): Add explicit braces to
> 	resolve a future -Wparentheses warning.
> 	* omp-low.c (scan_sharing_clauses): Likewise.

Forgot about a tree-parloops.c change:

diff:

diff --git a/gcc/tree-parloops.c b/gcc/tree-parloops.c
index e498e5b..2e55b79 100644
--- a/gcc/tree-parloops.c
+++ b/gcc/tree-parloops.c
@@ -767,14 +767,16 @@ eliminate_local_variables (edge entry, edge exit)
 
   FOR_EACH_VEC_ELT (body, i, bb)
     if (bb != entry_bb && bb != exit_bb)
-      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
-	if (is_gimple_debug (gsi_stmt (gsi)))
-	  {
-	    if (gimple_debug_bind_p (gsi_stmt (gsi)))
-	      has_debug_stmt = true;
-	  }
-	else
-	  eliminate_local_variables_stmt (entry, &gsi, &decl_address);
+      {
+        for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	  if (is_gimple_debug (gsi_stmt (gsi)))
+	    {
+	      if (gimple_debug_bind_p (gsi_stmt (gsi)))
+	        has_debug_stmt = true;
+	    }
+	  else
+	    eliminate_local_variables_stmt (entry, &gsi, &decl_address);
+      }
 
   if (has_debug_stmt)
     FOR_EACH_VEC_ELT (body, i, bb)


diff -w:

diff --git a/gcc/tree-parloops.c b/gcc/tree-parloops.c
index e498e5b..2e55b79 100644
--- a/gcc/tree-parloops.c
+++ b/gcc/tree-parloops.c
@@ -767,6 +767,7 @@ eliminate_local_variables (edge entry, edge exit)
 
   FOR_EACH_VEC_ELT (body, i, bb)
     if (bb != entry_bb && bb != exit_bb)
+      {
         for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 	  if (is_gimple_debug (gsi_stmt (gsi)))
 	    {
@@ -775,6 +776,7 @@ eliminate_local_variables (edge entry, edge exit)
 	    }
 	  else
 	    eliminate_local_variables_stmt (entry, &gsi, &decl_address);
+      }
 
   if (has_debug_stmt)
     FOR_EACH_VEC_ELT (body, i, bb)