diff options
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/ifcvt.c | 17 |
2 files changed, 17 insertions, 6 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index ddaa543396f..24a3187dbd2 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2000-04-30 Richard Henderson <rth@cygnus.com> + + * ifcvt.c (noce_process_if_block): Fail the conversion if X is + referenced bewteen the condition and the jump. Don't delete + anything but the jump. + Sun Apr 30 22:48:24 2000 Jason Eckhardt <jle@cygnus.com> * bb-reorder.c (scope_def): New struct. diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c index b831b3e14d2..ba310da9d84 100644 --- a/gcc/ifcvt.c +++ b/gcc/ifcvt.c @@ -1024,7 +1024,7 @@ noce_process_if_block (test_bb, then_bb, else_bb, join_bb) rtx insn_a, insn_b; rtx set_a, set_b; rtx orig_x, x, a, b; - rtx jump, cond; + rtx jump, cond, insn; /* If this is not a standard conditional jump, we can't parse it. */ jump = test_bb->end; @@ -1046,6 +1046,11 @@ noce_process_if_block (test_bb, then_bb, else_bb, join_bb) x = SET_DEST (set_a); a = SET_SRC (set_a); + /* X may not be mentioned between cond_earliest and the jump. */ + for (insn = jump; insn != if_info.cond_earliest; insn = PREV_INSN (insn)) + if (INSN_P (insn) && reg_mentioned_p (x, insn)) + return FALSE; + /* Look for the other potential set. Make sure we've got equivalent destinations. */ /* ??? This is overconservative. Storing to two different mems is @@ -1165,10 +1170,10 @@ noce_process_if_block (test_bb, then_bb, else_bb, join_bb) } /* The new insns will have been inserted before cond_earliest. We should - be able to remove cond_earliest through the jump with impunity. */ - insn_a = prev_nonnote_insn (if_info.cond_earliest); - flow_delete_insn_chain (if_info.cond_earliest, test_bb->end); - test_bb->end = insn_a; + be able to remove the jump with impunity, but the condition itself may + have been modified by gcse to be shared across basic blocks. */ + test_bb->end = PREV_INSN (jump); + flow_delete_insn (jump); /* If we used a temporary, fix it up now. */ if (orig_x != x) @@ -1178,7 +1183,7 @@ noce_process_if_block (test_bb, then_bb, else_bb, join_bb) insn_b = gen_sequence (); end_sequence (); - test_bb->end = emit_insn_after (insn_b, insn_a); + test_bb->end = emit_insn_after (insn_b, test_bb->end); } /* Merge the blocks! */ |