https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77750
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Comment on attachment 39694 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39694 Possible patch (correctly formatted magic "fall through" comments) >Index: gcc/combine.c >=================================================================== >--- gcc/combine.c (revision 240520) >+++ gcc/combine.c (working copy) >@@ -11370,6 +11370,8 @@ simplify_compare_const (enum rtx_code code, machin > else > break; > >+ /* fall through. */ >+ Yes this is correct but maybe it is better to rewrite this code slightly: if (const_op <= 0) break; const_op -= 1; code = LE; /* fall through. */ > case LE: > /* <= C is equivalent to < (C + 1); we do this for C < 0 */ > if (const_op < 0) >@@ -11399,6 +11401,8 @@ simplify_compare_const (enum rtx_code code, machin > else > break; > >+ /* fall through. */ Likewise. >+ > case GT: > /* > C is equivalent to >= (C + 1); we do this for C < 0. */ > if (const_op < 0) >@@ -11927,7 +11931,7 @@ simplify_comparison (enum rtx_code code, rtx *pop0 > else > break; > >- /* ... fall through ... */ >+ /* fall through. */ Likewise. > > case ZERO_EXTEND: > mode = GET_MODE (XEXP (op0, 0)); >@@ -12339,7 +12343,8 @@ simplify_comparison (enum rtx_code code, rtx *pop0 > continue; > } > >- /* ... fall through ... */ >+ /* fall through. */ Do something similar: /* If the inner mode is narrower and we are extracting the low part, we can treat the SUBREG as if it were a ZERO_EXTEND. */ if (!subreg_lowpart_p (op0) &|| GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op0))) >= mode_width) break; /* fall through */ >+ > case LSHIFTRT: > /* If we have (compare (xshiftrt FOO N) (const_int C)) and > the low order N bits of FOO are known to be zero, we can do this >Index: gcc/fold-const.c >=================================================================== >--- gcc/fold-const.c (revision 240520) >+++ gcc/fold-const.c (working copy) >@@ -6284,7 +6284,7 @@ extract_muldiv_1 (tree t, tree c, enum tree_code c > return omit_one_operand (type, integer_zero_node, op0); > } > >- /* ... fall through ... */ >+ /* fall through. */ This one is obvious. > > case TRUNC_DIV_EXPR: case CEIL_DIV_EXPR: case FLOOR_DIV_EXPR: > case ROUND_DIV_EXPR: case EXACT_DIV_EXPR:
