On 02/15/2017 09:49 AM, Martin Liška wrote:
Hi.
As mentioned in the PR, gimple nops are wrongly handled in is_maybe_undefined
function.
Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.
gimple *def = SSA_NAME_DEF_STMT (t);
+ if (!def || gimple_nop_p (def))
+ return true;
+
Out of curiosity, what is T?
Because we early bail out if ssa_undefined_value_p() right before
calling SSA_NAME_DEF_STMT, and ssa_undefined_value_p() will already bail
if gimple_nop_p.
So T must be one of:
/* Parameters get their initial value from the function entry. */
else if (TREE_CODE (var) == PARM_DECL)
return false;
/* When returning by reference the return address is actually a hidden
parameter. */
else if (TREE_CODE (var) == RESULT_DECL && DECL_BY_REFERENCE (var))
return false;
/* Hard register variables get their initial value from the ether. */
else if (VAR_P (var) && DECL_HARD_REGISTER (var))
return false;
which I wonder if we should special case in is_maybe_undefined.
Aldy
