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| author | J"orn Rennecke <amylaar@cygnus.co.uk> | 1999-02-04 23:10:46 +0000 |
|---|---|---|
| committer | Joern Rennecke <amylaar@gcc.gnu.org> | 1999-02-04 23:10:46 +0000 |
| commit | 2d4fde68c33a27b8125ab8afabcfc039eca51ab6 (patch) | |
| tree | cec55d3649e704607bb5cb8a874ab831735923fb | |
| parent | a5af23fe121ce80395777cd066f04699e56240e0 (diff) | |
| download | gcc-2d4fde68c33a27b8125ab8afabcfc039eca51ab6.zip gcc-2d4fde68c33a27b8125ab8afabcfc039eca51ab6.tar.gz gcc-2d4fde68c33a27b8125ab8afabcfc039eca51ab6.tar.bz2 | |
loop.c (first_loop_store_insn): New file-scope variable.
* loop.c (first_loop_store_insn): New file-scope variable.
(prescan_loop): Set it.
(check_dbra_loop): Check if a store depends on a register
that is set after the store.
From-SVN: r25034
| -rw-r--r-- | gcc/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/loop.c | 29 |
2 files changed, 33 insertions, 3 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 6c7fa58..e2edb46 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +Fri Feb 5 07:09:29 1999 J"orn Rennecke <amylaar@cygnus.co.uk> + + * loop.c (first_loop_store_insn): New file-scope variable. + (prescan_loop): Set it. + (check_dbra_loop): Check if a store depends on a register + that is set after the store. + Fri Feb 5 06:55:15 1999 J"orn Rennecke <amylaar@cygnus.co.uk> * unroll.c (entire file): Remove tabs / spaces at end of lines. @@ -173,6 +173,9 @@ static char *moved_once; static rtx loop_store_mems; +/* The insn where the first of these was found. */ +static rtx first_loop_store_insn; + typedef struct loop_mem_info { rtx mem; /* The MEM itself. */ rtx reg; /* Corresponding pseudo, if any. */ @@ -2404,6 +2407,7 @@ prescan_loop (start, end) loop_has_volatile = 0; loop_has_tablejump = 0; loop_store_mems = NULL_RTX; + first_loop_store_insn = NULL_RTX; loop_mems_idx = 0; num_mem_sets = 0; @@ -2456,6 +2460,8 @@ prescan_loop (start, end) loop_has_tablejump = 1; note_stores (PATTERN (insn), note_addr_stored); + if (! first_loop_store_insn && loop_store_mems) + first_loop_store_insn = insn; if (! loop_has_multiple_exit_targets && GET_CODE (insn) == JUMP_INSN @@ -7682,9 +7688,26 @@ check_dbra_loop (loop_end, insn_count, loop_start, loop_info) case, the insn should have been moved out of the loop. */ if (num_mem_sets == 1) - reversible_mem_store - = (! unknown_address_altered - && ! invariant_p (XEXP (loop_store_mems, 0))); + { + struct induction *v; + + reversible_mem_store + = (! unknown_address_altered + && ! invariant_p (XEXP (loop_store_mems, 0))); + + /* If the store depends on a register that is set after the + store, it depends on the initial value, and is thus not + reversible. */ + for (v = bl->giv; reversible_mem_store && v; v = v->next_iv) + { + if (v->giv_type == DEST_REG + && reg_mentioned_p (v->dest_reg, + XEXP (loop_store_mems, 0)) + && (INSN_LUID (v->insn) + > INSN_LUID (first_loop_store_insn))) + reversible_mem_store = 0; + } + } } else return 0; |