diff options
Diffstat (limited to 'gcc/cse.c')
| -rw-r--r-- | gcc/cse.c | 20 |
1 files changed, 18 insertions, 2 deletions
@@ -1,6 +1,6 @@ /* Common subexpression elimination for GNU compiler. Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998 - 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc. + 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc. This file is part of GCC. @@ -7108,6 +7108,7 @@ cse_basic_block (rtx from, rtx to, struct branch_path *next_branch, int to_usage = 0; rtx libcall_insn = NULL_RTX; int num_insns = 0; + int no_conflict = 0; /* This array is undefined before max_reg, so only allocate the space actually needed and adjust the start. */ @@ -7187,11 +7188,26 @@ cse_basic_block (rtx from, rtx to, struct branch_path *next_branch, if ((p = find_reg_note (insn, REG_LIBCALL, NULL_RTX))) libcall_insn = XEXP (p, 0); else if (find_reg_note (insn, REG_RETVAL, NULL_RTX)) - libcall_insn = 0; + { + /* Keep libcall_insn for the last SET insn of a no-conflict + block to prevent changing the destination. */ + if (! no_conflict) + libcall_insn = 0; + else + no_conflict = -1; + } + else if (find_reg_note (insn, REG_NO_CONFLICT, NULL_RTX)) + no_conflict = 1; } cse_insn (insn, libcall_insn); + if (no_conflict == -1) + { + libcall_insn = 0; + no_conflict = 0; + } + /* If we haven't already found an insn where we added a LABEL_REF, check this one. */ if (GET_CODE (insn) == INSN && ! recorded_label_ref |