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tree-ssa-uninit.c (warn_uninitialized_vars): Don't warn about memory accesses where the use is for the first operand of a...

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2017-07-25  Andrew Pinski  <apinski@cavium.com>

        * tree-ssa-uninit.c (warn_uninitialized_vars): Don't warn about memory
        accesses where the use is for the first operand of a BIT_INSERT.

From-SVN: r250530
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Andrew Pinski 2017-07-25 17:17:46 +00:00 • committed by Andrew Pinski
parent 50ca694de2
commit 6d20bf1870
2 changed files with 30 additions and 0 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2017-07-25 Andrew Pinski <apinski@cavium.com>
* tree-ssa-uninit.c (warn_uninitialized_vars): Don't warn about memory
accesses where the use is for the first operand of a BIT_INSERT.
2017-07-25 Jim Wilson <jim.wilson@linaro.org>
PR bootstrap/81521

25
gcc/tree-ssa-uninit.c
View file

@ -273,6 +273,11 @@ warn_uninitialized_vars (bool warn_possibly_uninitialized)
&& gimple_has_location (stmt))
{
tree rhs = gimple_assign_rhs1 (stmt);
tree lhs = gimple_assign_lhs (stmt);
bool has_bit_insert = false;
use_operand_p luse_p;
imm_use_iterator liter;
if (TREE_NO_WARNING (rhs))
continue;
@ -300,6 +305,26 @@ warn_uninitialized_vars (bool warn_possibly_uninitialized)
ref.offset) <= 0)))
continue;
/* Do not warn if the access is then used for a BIT_INSERT_EXPR. */
if (TREE_CODE (lhs) == SSA_NAME)
FOR_EACH_IMM_USE_FAST (luse_p, liter, lhs)
{
gimple *use_stmt = USE_STMT (luse_p);
/* BIT_INSERT_EXPR first operand should not be considered
a use for the purpose of uninit warnings. */
if (gassign *ass = dyn_cast <gassign *> (use_stmt))
{
if (gimple_assign_rhs_code (ass) == BIT_INSERT_EXPR
&& luse_p->use == gimple_assign_rhs1_ptr (ass))
{
has_bit_insert = true;
break;
}
}
}
if (has_bit_insert)
continue;
/* Limit the walking to a constant number of stmts after
we overcommit quadratic behavior for small functions
and O(n) behavior. */