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Remove unreachable gcc_unreachable () at the end of functions

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It seems to be a style to place gcc_unreachable () after a
switch that handles all cases with every case returning.
Those are unreachable (well, yes!), so they will be elided
at CFG construction time and the middle-end will place
another __builtin_unreachable "after" them to note the
path doesn't lead to a return when the function is not declared
void.

So IMHO those explicit gcc_unreachable () serve no purpose,
if they could be replaced by a comment.  But since all cases
cover switches not handling a case or not returning will
likely cause some diagnostic to be emitted which is better
than running into an ICE only at runtime.

2021-11-24  Richard Biener  <rguenther@suse.de>

	* tree.h (reverse_storage_order_for_component_p): Remove
	spurious gcc_unreachable.
	* cfganal.c (dfs_find_deadend): Likewise.
	* fold-const-call.c (fold_const_logb): Likewise.
	(fold_const_significand): Likewise.
	* gimple-ssa-store-merging.c (lhs_valid_for_store_merging_p):
	Likewise.

gcc/c-family/
	* c-format.c (check_format_string): Remove spurious
	gcc_unreachable.
This commit is contained in:
Richard Biener 2021-11-24 15:57:03 +01:00
parent 16507dea75
commit a3b31fe369
5 changed files with 0 additions and 10 deletions
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2
gcc/c-family/c-format.c
View file

@ -296,8 +296,6 @@ check_format_string (const_tree fntype, unsigned HOST_WIDE_INT format_num,
*no_add_attrs = true;
return false;
}
gcc_unreachable ();
}
/* Under the control of FLAGS, verify EXPR is a valid constant that

2
gcc/cfganal.c
View file

@ -752,8 +752,6 @@ dfs_find_deadend (basic_block bb)
next = e ? e->dest : EDGE_SUCC (bb, 0)->dest;
}
}
gcc_unreachable ();
}

2
gcc/fold-const-call.c
View file

@ -429,7 +429,6 @@ fold_const_logb (real_value *result, const real_value *arg,
}
return false;
}
gcc_unreachable ();
}
/* Try to evaluate:
@ -463,7 +462,6 @@ fold_const_significand (real_value *result, const real_value *arg,
}
return false;
}
gcc_unreachable ();
}
/* Try to evaluate:

2
gcc/gimple-ssa-store-merging.c
View file

@ -4867,8 +4867,6 @@ lhs_valid_for_store_merging_p (tree lhs)
default:
return false;
}
gcc_unreachable ();
}
/* Return true if the tree RHS is a constant we want to consider

2
gcc/tree.h
View file

@ -5110,8 +5110,6 @@ reverse_storage_order_for_component_p (tree t)
default:
return false;
}
gcc_unreachable ();
}
/* Return true if T is a storage order barrier, i.e. a VIEW_CONVERT_EXPR