diff options
| author | bonzini <bonzini@138bc75d-0d04-0410-961f-82ee72b054a4> | 2007-12-14 17:40:46 +0000 |
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| committer | bonzini <bonzini@138bc75d-0d04-0410-961f-82ee72b054a4> | 2007-12-14 17:40:46 +0000 |
| commit | 84da895440a5f84f551c56edb5557b9e536c0439 (patch) | |
| tree | a0bfa427f7b8eddddeb56a76dc1d3684d9e702c0 /gcc/df-problems.c | |
| parent | 18f95a3608ef0e138e060663adde716064ea649b (diff) | |
| download | gcc-84da895440a5f84f551c56edb5557b9e536c0439.tar.gz | |
2007-12-14 Paolo Bonzini <bonzini@gnu.org>
* df-core.c: Update comments referring to removed features.
* df-problems.c: Likewise.
* df-scan.c: Likewise.
* df.h: Likewise.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@130937 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/df-problems.c')
| -rw-r--r-- | gcc/df-problems.c | 36 |
1 files changed, 19 insertions, 17 deletions
diff --git a/gcc/df-problems.c b/gcc/df-problems.c index dd56399be50..ed56c7feec5 100644 --- a/gcc/df-problems.c +++ b/gcc/df-problems.c @@ -1304,16 +1304,22 @@ df_lr_verify_transfer_functions (void) /*---------------------------------------------------------------------------- - COMBINED LIVE REGISTERS AND UNINITIALIZED REGISTERS. - - First find the set of uses for registers that are reachable from - the entry block without passing thru a definition. In and out - bitvectors are built for each basic block. The regnum is used to - index into these sets. See df.h for details. - - Then the in and out sets here are the anded results of the in and - out sets from the lr and ur - problems. + LIVE AND MUST-INITIALIZED REGISTERS. + + This problem first computes the IN and OUT bitvectors for the + must-initialized registers problems, which is a forward problem. + It gives the set of registers for which we MUST have an available + definition on any path from the entry block to the entry/exit of + a basic block. Sets generate a definition, while clobbers kill + a definition. + + In and out bitvectors are built for each basic block and are indexed by + regnum (see df.h for details). In and out bitvectors in struct + df_live_bb_info actually refers to the must-initialized problem; + + Then, the in and out sets for the LIVE problem itself are computed. + These are the logical AND of the IN and OUT sets from the LR problem + and the must-initialized problem. ----------------------------------------------------------------------------*/ /* Private data used to verify the solution for this problem. */ @@ -1510,7 +1516,7 @@ df_live_init (bitmap all_blocks) } } -/* Confluence function that ignores fake edges. */ +/* Forward confluence function that ignores fake edges. */ static void df_live_confluence_n (edge e) @@ -1525,7 +1531,7 @@ df_live_confluence_n (edge e) } -/* Transfer function. */ +/* Transfer function for the forwards must-initialized problem. */ static bool df_live_transfer_function (int bb_index) @@ -1540,7 +1546,7 @@ df_live_transfer_function (int bb_index) } -/* And the LR and UR info to produce the LIVE info. */ +/* And the LR info with the must-initialized registers, to produce the LIVE info. */ static void df_live_local_finalize (bitmap all_blocks) @@ -2916,10 +2922,6 @@ static struct df_problem problem_NOTE = NULL, /* Debugging end block. */ NULL, /* Incremental solution verify start. */ NULL, /* Incremental solution verify end. */ - - /* Technically this is only dependent on the live registers problem - but it will produce information if built one of uninitialized - register problems (UR, UREC) is also run. */ &problem_LR, /* Dependent problem. */ TV_DF_NOTE, /* Timing variable. */ false /* Reset blocks on dropping out of blocks_to_analyze. */ |