Hi, layers_id_colors_and_visibility.h defines enum LAYER_ID as unsigned, then #defines two negative constants to be used with the enum. Comparisons of these generate the following warning:
warning: comparison of constant 4294967295 with expression of type 'int' is always true [-Wtautological-constant-out-of-range-compare] Currently there is no problem (I actually dug into the assembler to make sure the comparison was being generated). However, this is a time bomb just waiting for a different compiler version which decides to optimize out what it sees as a tautological comparison, and the fix is very, very simple. Attached patch does two things: 1) Move the negative constants INTO the enum so that the compiler knows to assign the enum a backing type that supports negatives. 2) Remove the unnecessary forced-typing of the enum. There is absolutely no reason this enum has to be an unsigned-char; I suspect this was an instance of overzealous and misguided "optimization". This "optimization" will at best not do anything (as the compiler will decide to pad out the char to the platform's word length anyway), and at worst make things even /slower/ (if the compiler actually decides to access it as a char). -- Chris
commit ad4a1b6d2a938b8d108000a5799b47618112c0ad Author: Chris Pavlina <[email protected]> Date: Tue Jan 5 11:02:13 2016 -0500 Fix enum comparison warning diff --git a/include/layers_id_colors_and_visibility.h b/include/layers_id_colors_and_visibility.h index b424aea..db72495 100644 --- a/include/layers_id_colors_and_visibility.h +++ b/include/layers_id_colors_and_visibility.h @@ -54,9 +54,6 @@ typedef int LAYER_NUM; * One of these cannot be "incremented". */ enum LAYER_ID -#if __cplusplus >= 201103L - : unsigned char -#endif { F_Cu, // 0 In1_Cu, @@ -116,12 +113,12 @@ enum LAYER_ID B_Fab, F_Fab, - LAYER_ID_COUNT -}; + LAYER_ID_COUNT, + UNDEFINED_LAYER = -1, + UNSELECTED_LAYER = -2, +}; -#define UNDEFINED_LAYER LAYER_ID(-1) -#define UNSELECTED_LAYER LAYER_ID(-2) #define MAX_CU_LAYERS (B_Cu - F_Cu + 1)
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