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| author | Richard Kenner <kenner@vlsi1.ultra.nyu.edu> | 2000-05-31 11:58:35 +0000 |
|---|---|---|
| committer | Richard Kenner <kenner@gcc.gnu.org> | 2000-05-31 07:58:35 -0400 |
| commit | 8c410416207d0fd87d574c621eaacfb74588c47e (patch) | |
| tree | 27d600ce15ff0bdab4697a43d2848886d96aed6d /gcc/flow.c | |
| parent | efd58783444cdeb32ac41a9a1bc645e9544e8c1f (diff) | |
| download | gcc-8c410416207d0fd87d574c621eaacfb74588c47e.zip gcc-8c410416207d0fd87d574c621eaacfb74588c47e.tar.gz gcc-8c410416207d0fd87d574c621eaacfb74588c47e.tar.bz2 | |
flow.c (propagate_block): If block has no successors, stores to frame are dead if not used.
* flow.c (propagate_block): If block has no successors, stores to
frame are dead if not used.
From-SVN: r34296
Diffstat (limited to 'gcc/flow.c')
| -rw-r--r-- | gcc/flow.c | 20 |
1 files changed, 20 insertions, 0 deletions
@@ -3772,6 +3772,26 @@ propagate_block (bb, live, local_set, flags) { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; }); } + /* If this block has no successors, any stores to the frame that aren't + used later in the block are dead. So make a pass over the block + recording any such that are made and show them dead at the end. We do + a very conservative and simple job here. */ + if (bb->succ != 0 && bb->succ->succ_next == 0 + && bb->succ->dest == EXIT_BLOCK_PTR) + for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn)) + if (GET_CODE (insn) == INSN && GET_CODE (PATTERN (insn)) == SET + && GET_CODE (SET_DEST (PATTERN (insn))) == MEM) + { + rtx mem = SET_DEST (PATTERN (insn)); + + if ((GET_CODE (XEXP (mem, 0)) == REG + && REGNO (XEXP (mem, 0)) == FRAME_POINTER_REGNUM) + || (GET_CODE (XEXP (mem, 0)) == PLUS + && GET_CODE (XEXP (XEXP (mem, 0), 0)) == REG + && REGNO (XEXP (XEXP (mem, 0), 0)) == FRAME_POINTER_REGNUM)) + pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list); + } + /* Scan the block an insn at a time from end to beginning. */ for (insn = bb->end; ; insn = prev) |