[gcc r14-10346] Fix PR c/115587, uninitialized variable in c_parser_omp_loop_nest

[Sandra Loosemore]

https://gcc.gnu.org/g:b383719aebe45bbe8cc3944e515ed7caa30e8744

commit r14-10346-gb383719aebe45bbe8cc3944e515ed7caa30e8744
Author: Sandra Loosemore <sloosemore@baylibre.com>
Date:   Tue Jun 25 13:54:43 2024 +0000

    Fix PR c/115587, uninitialized variable in c_parser_omp_loop_nest
    
    This function had a reference to an uninitialized variable on the
    error path.  The problem was diagnosed by clang but not gcc.  It seems
    the cleanest solution is to initialize all the loop-clause variables
    at the point of declaration rather than at different places in the
    code.
    
    The C++ front end didn't have this problem, but I've made similar
    changes there to keep the code in sync.
    
    gcc/c/ChangeLog:
    
            PR c/115587
            * c-parser.cc (c_parser_omp_loop_nest): Move initializations to
            point of declaration.
    
    gcc/cp/ChangeLog:
    
            PR c/115587
            * parser.cc (cp_parser_omp_loop_nest): Move initializations to
            point of declaration.
    
    (cherry picked from commit 21f1073d388af8af207183b0ed592e1cc47d20ab)

Diff:
---
 gcc/c/c-parser.cc | 4 +---
 gcc/cp/parser.cc  | 8 ++------
 2 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 00f8bf4376e..5fcfff7134a 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -22240,7 +22240,7 @@ c_parser_omp_scan_loop_body (c_parser *parser, bool open_brace_parsed)
 static tree
 c_parser_omp_loop_nest (c_parser *parser, bool *if_p)
 {
-  tree decl, cond, incr, init;
+  tree decl = NULL_TREE, cond = NULL_TREE, incr = NULL_TREE, init = NULL_TREE;
   tree body = NULL_TREE;
   matching_parens parens;
   bool moreloops;
@@ -22330,7 +22330,6 @@ c_parser_omp_loop_nest (c_parser *parser, bool *if_p)
     }
 
   /* Parse the loop condition.  */
-  cond = NULL_TREE;
   if (c_parser_next_token_is_not (parser, CPP_SEMICOLON))
     {
       location_t cond_loc = c_parser_peek_token (parser)->location;
@@ -22363,7 +22362,6 @@ c_parser_omp_loop_nest (c_parser *parser, bool *if_p)
   c_parser_skip_until_found (parser, CPP_SEMICOLON, "expected %<;%>");
 
   /* Parse the increment expression.  */
-  incr = NULL_TREE;
   if (c_parser_next_token_is_not (parser, CPP_CLOSE_PAREN))
     {
       location_t incr_loc = c_parser_peek_token (parser)->location;
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 6b786ed8266..7e81c1010c4 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -44756,8 +44756,8 @@ cp_parser_omp_scan_loop_body (cp_parser *parser)
 static tree
 cp_parser_omp_loop_nest (cp_parser *parser, bool *if_p)
 {
-  tree decl, cond, incr, init;
-  tree orig_init, real_decl, orig_decl;
+  tree decl = NULL_TREE, cond = NULL_TREE, incr = NULL_TREE, init = NULL_TREE;
+  tree orig_init = NULL_TREE, real_decl = NULL_TREE, orig_decl = NULL_TREE;
   tree init_block, body_block;
   tree init_placeholder, body_placeholder;
   tree init_scope;
@@ -44793,8 +44793,6 @@ cp_parser_omp_loop_nest (cp_parser *parser, bool *if_p)
   if (!parens.require_open (parser))
     return NULL;
 
-  init = orig_init = decl = real_decl = orig_decl = NULL_TREE;
-
   init_placeholder = build_stmt (input_location, EXPR_STMT,
 				 integer_zero_node);
   vec_safe_push (omp_for_parse_state->init_placeholderv, init_placeholder);
@@ -44970,12 +44968,10 @@ cp_parser_omp_loop_nest (cp_parser *parser, bool *if_p)
 	}
     }
 
-  cond = NULL;
   if (cp_lexer_next_token_is_not (parser->lexer, CPP_SEMICOLON))
     cond = cp_parser_omp_for_cond (parser, decl, omp_for_parse_state->code);
   cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
 
-  incr = NULL;
   if (cp_lexer_next_token_is_not (parser->lexer, CPP_CLOSE_PAREN))
     {
       /* If decl is an iterator, preserve the operator on decl