From 8e0b124eafae477ce0e3d8efc891dadd95038b71 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Wed, 14 Feb 2001 10:34:25 -0800 Subject: [PATCH] jump.c (jump_optimize_1): When we delete a conditional jump preceeding a non-conditional jump to... * jump.c (jump_optimize_1): When we delete a conditional jump preceeding a non-conditional jump to effectively the same place, make sure that the combined jump skips any clobber insns between the two labels. Co-Authored-By: DJ Delorie From-SVN: r39686 --- gcc/ChangeLog | 8 ++++++++ gcc/jump.c | 22 ++++++++++++++++++++++ 2 files changed, 30 insertions(+) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 63bbb9bff3f..a97e22abc24 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2001-02-14 Richard Henderson + DJ Delorie + + * jump.c (jump_optimize_1): When we delete a conditional jump + preceeding a non-conditional jump to effectively the same place, + make sure that the combined jump skips any clobber insns between + the two labels. + 2001-02-14 Jeffrey Oldham * gcc.c (do_spec_1): Fix off-by-one error for '%M' case. diff --git a/gcc/jump.c b/gcc/jump.c index 978b2666a0e..121375395bd 100644 --- a/gcc/jump.c +++ b/gcc/jump.c @@ -420,6 +420,28 @@ jump_optimize_1 (f, cross_jump, noop_moves, after_regscan, if (temp2 == temp) { + /* Ensure that we jump to the later of the two labels. + Consider: + + if (test) goto L2; + goto L1; + ... + L1: + (clobber return-reg) + L2: + (use return-reg) + + If we leave the goto L1, we'll incorrectly leave + return-reg dead for TEST true. */ + + temp2 = next_active_insn (JUMP_LABEL (insn)); + if (!temp2) + temp2 = get_last_insn (); + if (GET_CODE (temp2) != CODE_LABEL) + temp2 = prev_label (temp2); + if (temp2 != JUMP_LABEL (temp)) + redirect_jump (temp, temp2, 1); + delete_jump (insn); changed = 1; continue; -- 2.30.2