[Bug tree-optimization/108457] [13 Regression] tree-ssa-loop-niter.cc:2255:23: warning: variable 'mode' set but not used
pinskia at gcc dot gnu.org
gcc-bugzilla@gcc.gnu.org
Wed Jan 18 21:07:12 GMT 2023
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108457
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|tree-ssa-loop-niter.cc:2255 |[13 Regression]
|:23: warning: variable |tree-ssa-loop-niter.cc:2255
|'mode' set but not used |:23: warning: variable
| |'mode' set but not used
Component|bootstrap |tree-optimization
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
Keywords| |build
Target Milestone|--- |13.0
Last reconfirmed| |2023-01-18
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Basically C[TL]Z_DEFINED_VALUE_AT_ZERO macro does not always use its arguments
so they don't get marked as used ...
Simple patch:
diff --git a/gcc/tree-ssa-loop-niter.cc b/gcc/tree-ssa-loop-niter.cc
index 65b960461ae..22e7c0f6ea5 100644
--- a/gcc/tree-ssa-loop-niter.cc
+++ b/gcc/tree-ssa-loop-niter.cc
@@ -2253,6 +2253,8 @@ build_cltz_expr (tree src, bool leading, bool
define_at_zero)
integer_type_node, 1, src);
int val;
scalar_int_mode mode = SCALAR_INT_TYPE_MODE (utype);
+ /* mode might not be used by the macro C[TL]Z_DEFINED_AT_ZERO. */
+ (void)mode;
int optab_defined_at_zero
= leading ? CLZ_DEFINED_VALUE_AT_ZERO (mode, val)
: CTZ_DEFINED_VALUE_AT_ZERO (mode, val);
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