diff options
Diffstat (limited to 'gcc/final.c')
| -rw-r--r-- | gcc/final.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/gcc/final.c b/gcc/final.c index 0938e221d5e..454ab6c71f5 100644 --- a/gcc/final.c +++ b/gcc/final.c @@ -1980,6 +1980,18 @@ final (first, file, optimize, prescan) max_uid = INSN_UID (insn); if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) > 0) line_note_exists[NOTE_LINE_NUMBER (insn)] = 1; +#ifdef HAVE_cc0 + /* If CC tracking across branches is enabled, record the insn which + jumps to each branch only reached from one place. */ + if (GET_CODE (insn) == JUMP_INSN) + { + rtx lab = JUMP_LABEL (insn); + if (lab && LABEL_NUSES (lab) == 1) + { + LABEL_REFS (lab) = insn; + } + } +#endif } /* Initialize insn_eh_region table if eh is being used. */ @@ -2283,7 +2295,30 @@ final_scan_insn (insn, file, optimize, prescan, nopeepholes) ASM_OUTPUT_ALIGN (file, align); #endif } +#ifdef HAVE_cc0 CC_STATUS_INIT; + /* If this label is reached from only one place, set the condition + codes from the instruction just before the branch. */ + if (LABEL_NUSES (insn) == 1) + { + rtx jump = LABEL_REFS (insn); + rtx barrier = prev_nonnote_insn (insn); + rtx prev; + /* If the LABEL_REFS field of this label has been set to point + at a branch, the predecessor of the branch is a regular + insn, and that branch is the only way to reach this label, + set the condition codes based on the branch and its + predecessor. */ + if (barrier && GET_CODE (barrier) == BARRIER + && jump && GET_CODE (jump) == JUMP_INSN + && (prev = prev_nonnote_insn (jump)) + && GET_CODE (prev) == INSN) + { + NOTICE_UPDATE_CC (PATTERN (prev), prev); + NOTICE_UPDATE_CC (PATTERN (jump), jump); + } + } +#endif if (prescan > 0) break; new_block = 1; |