From bf22920b4a994c29b01c0fff1232ef3f3c451895 Mon Sep 17 00:00:00 2001 From: Tom de Vries Date: Thu, 7 Apr 2011 09:48:39 +0000 Subject: [PATCH] re PR target/43920 (Choosing conditional execution over conditional branches for code size in some cases.) 2011-04-07 Tom de Vries PR target/43920 * cfgcleanup.c (try_crossjump_to_edge): Add dir parameter. Pass dir to flow_find_cross_jump. Swap variables to implement backward replacement. (try_crossjump_bb): Add argument to try_crossjump_to_edge. From-SVN: r172094 --- gcc/ChangeLog | 7 +++++++ gcc/cfgcleanup.c | 27 ++++++++++++++++++++------- 2 files changed, 27 insertions(+), 7 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 8594a769076..7d80ceaf10e 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2011-04-07 Tom de Vries + + PR target/43920 + * cfgcleanup.c (try_crossjump_to_edge): Add dir parameter. Pass dir to + flow_find_cross_jump. Swap variables to implement backward replacement. + (try_crossjump_bb): Add argument to try_crossjump_to_edge. + 2011-04-07 Tom de Vries PR target/43920 diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c index 27af12f6437..98c51ad2573 100644 --- a/gcc/cfgcleanup.c +++ b/gcc/cfgcleanup.c @@ -69,7 +69,7 @@ static bool crossjumps_occured; information; we should run df_analyze to enable more opportunities. */ static bool block_was_dirty; -static bool try_crossjump_to_edge (int, edge, edge); +static bool try_crossjump_to_edge (int, edge, edge, enum replace_direction); static bool try_crossjump_bb (int, basic_block); static bool outgoing_edges_match (int, basic_block, basic_block); static enum replace_direction old_insns_match_p (int, rtx, rtx); @@ -1761,16 +1761,18 @@ block_has_preserve_label (basic_block bb) /* E1 and E2 are edges with the same destination block. Search their predecessors for common code. If found, redirect control flow from - (maybe the middle of) E1->SRC to (maybe the middle of) E2->SRC. */ + (maybe the middle of) E1->SRC to (maybe the middle of) E2->SRC (dir_forward), + or the other way around (dir_backward). DIR specifies the allowed + replacement direction. */ static bool -try_crossjump_to_edge (int mode, edge e1, edge e2) +try_crossjump_to_edge (int mode, edge e1, edge e2, + enum replace_direction dir) { int nmatch; basic_block src1 = e1->src, src2 = e2->src; basic_block redirect_to, redirect_from, to_remove; basic_block osrc1, osrc2, redirect_edges_to, tmp; - enum replace_direction dir; rtx newpos1, newpos2; edge s; edge_iterator ei; @@ -1826,7 +1828,6 @@ try_crossjump_to_edge (int mode, edge e1, edge e2) return false; /* ... and part the second. */ - dir = dir_forward; nmatch = flow_find_cross_jump (src1, src2, &newpos1, &newpos2, &dir); osrc1 = src1; @@ -1836,6 +1837,16 @@ try_crossjump_to_edge (int mode, edge e1, edge e2) if (newpos2 != NULL_RTX) src2 = BLOCK_FOR_INSN (newpos2); + if (dir == dir_backward) + { +#define SWAP(T, X, Y) do { T tmp = (X); (X) = (Y); (Y) = tmp; } while (0) + SWAP (basic_block, osrc1, osrc2); + SWAP (basic_block, src1, src2); + SWAP (edge, e1, e2); + SWAP (rtx, newpos1, newpos2); +#undef SWAP + } + /* Don't proceed with the crossjump unless we found a sufficient number of matching instructions or the 'from' block was totally matched (such that its predecessors will hopefully be redirected and the @@ -2088,7 +2099,7 @@ try_crossjump_bb (int mode, basic_block bb) || (fallthru->src->flags & BB_MODIFIED))) continue; - if (try_crossjump_to_edge (mode, e, fallthru)) + if (try_crossjump_to_edge (mode, e, fallthru, dir_forward)) { changed = true; ix = 0; @@ -2136,7 +2147,9 @@ try_crossjump_bb (int mode, basic_block bb) || (e2->src->flags & BB_MODIFIED))) continue; - if (try_crossjump_to_edge (mode, e, e2)) + /* Both e and e2 are not fallthru edges, so we can crossjump in either + direction. */ + if (try_crossjump_to_edge (mode, e, e2, dir_both)) { changed = true; ix = 0; -- 2.30.2