Karl Meakin <karl.mea...@arm.com> writes: > Extract the hardcoded values for the minimum PC-relative displacements > into named constants and document them. > > gcc/ChangeLog: > > * config/aarch64/aarch64.md (BRANCH_LEN_P_128MiB): New constant. > (BRANCH_LEN_N_128MiB): Likewise. > (BRANCH_LEN_P_1MiB): Likewise. > (BRANCH_LEN_N_1MiB): Likewise. > (BRANCH_LEN_P_32KiB): Likewise. > (BRANCH_LEN_N_32KiB): Likewise. > --- > gcc/config/aarch64/aarch64.md | 64 ++++++++++++++++++++++++++--------- > 1 file changed, 48 insertions(+), 16 deletions(-) > > diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md > index d79b74924d4..c4c23dc3669 100644 > --- a/gcc/config/aarch64/aarch64.md > +++ b/gcc/config/aarch64/aarch64.md > @@ -704,7 +704,23 @@ (define_insn "jump" > [(set_attr "type" "branch")] > ) > > +;; Maximum PC-relative positive/negative displacements for various branching > +;; instructions. > +(define_constants > + [ > + ;; +/- 128MiB. Used by B, BL. > + (BRANCH_LEN_P_128MiB 134217724) > + (BRANCH_LEN_N_128MiB -134217728) > +
Sorry to be awkward, but: I was in the process of applying 1-5 locally with a view to pushing them when I noticed that this was never actually used, and isn't likely to be used in the foreseeable future. Would you mind dropping it? I don't think we should add dead code. Thanks, Richard > + ;; +/- 1MiB. Used by B.<cond>, CBZ, CBNZ. > + (BRANCH_LEN_P_1MiB 1048572) > + (BRANCH_LEN_N_1MiB -1048576) > > + ;; +/- 32KiB. Used by TBZ, TBNZ. > + (BRANCH_LEN_P_32KiB 32764) > + (BRANCH_LEN_N_32KiB -32768) > + ] > +) > > ;; ------------------------------------------------------------------- > ;; Conditional jumps > @@ -769,13 +785,17 @@ (define_insn "aarch64_bcond" > } > [(set_attr "type" "branch") > (set (attr "length") > - (if_then_else (and (ge (minus (match_dup 2) (pc)) (const_int -1048576)) > - (lt (minus (match_dup 2) (pc)) (const_int 1048572))) > + (if_then_else (and (ge (minus (match_dup 2) (pc)) > + (const_int BRANCH_LEN_N_1MiB)) > + (lt (minus (match_dup 2) (pc)) > + (const_int BRANCH_LEN_P_1MiB))) > (const_int 4) > (const_int 8))) > (set (attr "far_branch") > - (if_then_else (and (ge (minus (match_dup 2) (pc)) (const_int -1048576)) > - (lt (minus (match_dup 2) (pc)) (const_int 1048572))) > + (if_then_else (and (ge (minus (match_dup 2) (pc)) > + (const_int BRANCH_LEN_N_1MiB)) > + (lt (minus (match_dup 2) (pc)) > + (const_int BRANCH_LEN_P_1MiB))) > (const_int 0) > (const_int 1)))] > ) > @@ -830,13 +850,17 @@ (define_insn "aarch64_cbz<optab><mode>1" > } > [(set_attr "type" "branch") > (set (attr "length") > - (if_then_else (and (ge (minus (match_dup 1) (pc)) (const_int -1048576)) > - (lt (minus (match_dup 1) (pc)) (const_int 1048572))) > + (if_then_else (and (ge (minus (match_dup 1) (pc)) > + (const_int BRANCH_LEN_N_1MiB)) > + (lt (minus (match_dup 1) (pc)) > + (const_int BRANCH_LEN_P_1MiB))) > (const_int 4) > (const_int 8))) > (set (attr "far_branch") > - (if_then_else (and (ge (minus (match_dup 2) (pc)) (const_int -1048576)) > - (lt (minus (match_dup 2) (pc)) (const_int 1048572))) > + (if_then_else (and (ge (minus (match_dup 2) (pc)) > + (const_int BRANCH_LEN_N_1MiB)) > + (lt (minus (match_dup 2) (pc)) > + (const_int BRANCH_LEN_P_1MiB))) > (const_int 0) > (const_int 1)))] > ) > @@ -870,13 +894,17 @@ (define_insn "*aarch64_tbz<optab><mode>1" > } > [(set_attr "type" "branch") > (set (attr "length") > - (if_then_else (and (ge (minus (match_dup 1) (pc)) (const_int -32768)) > - (lt (minus (match_dup 1) (pc)) (const_int 32764))) > + (if_then_else (and (ge (minus (match_dup 1) (pc)) > + (const_int BRANCH_LEN_N_32KiB)) > + (lt (minus (match_dup 1) (pc)) > + (const_int BRANCH_LEN_P_32KiB))) > (const_int 4) > (const_int 8))) > (set (attr "far_branch") > - (if_then_else (and (ge (minus (match_dup 1) (pc)) (const_int -1048576)) > - (lt (minus (match_dup 1) (pc)) (const_int 1048572))) > + (if_then_else (and (ge (minus (match_dup 1) (pc)) > + (const_int BRANCH_LEN_N_1MiB)) > + (lt (minus (match_dup 1) (pc)) > + (const_int BRANCH_LEN_P_1MiB))) > (const_int 0) > (const_int 1)))] > ) > @@ -931,13 +959,17 @@ (define_insn "@aarch64_tbz<optab><ALLI:mode><GPI:mode>" > } > [(set_attr "type" "branch") > (set (attr "length") > - (if_then_else (and (ge (minus (match_dup 2) (pc)) (const_int -32768)) > - (lt (minus (match_dup 2) (pc)) (const_int 32764))) > + (if_then_else (and (ge (minus (match_dup 2) (pc)) > + (const_int BRANCH_LEN_N_32KiB)) > + (lt (minus (match_dup 2) (pc)) > + (const_int BRANCH_LEN_P_32KiB))) > (const_int 4) > (const_int 8))) > (set (attr "far_branch") > - (if_then_else (and (ge (minus (match_dup 2) (pc)) (const_int -1048576)) > - (lt (minus (match_dup 2) (pc)) (const_int 1048572))) > + (if_then_else (and (ge (minus (match_dup 2) (pc)) > + (const_int BRANCH_LEN_N_1MiB)) > + (lt (minus (match_dup 2) (pc)) > + (const_int BRANCH_LEN_P_1MiB))) > (const_int 0) > (const_int 1)))]
