This is my proposal of how to fix incorrect handling of a recursive
"(PHISOURCE->PHI->)+ PHISOURCE->PHI" chain in `phi_defines'.
It should be applied instead of my previous 2/2 patch posted on
2011-04-09 which treated this case unwisely as spotted by Chris Li
who also outlined respective correction in his reply from 2011-04-14.
The fix required to move `trackable_pseudo' (if we want to avoid
a forward declaration).
I also added `src_pseudo' in the role of a shortcut and removed `def' to
reduce the number of levels of such shortcuts (to keep it more readable).
I tried few comparisons (some of them in very carefully) and it seems to
do the job (as explained in included comment) right.
Signed-off-by: Jan Pokorny <pokorny_jan@xxxxxxxxx>
---
liveness.c | 39 +++++++++++++++++++++++++--------------
1 files changed, 25 insertions(+), 14 deletions(-)
diff --git a/liveness.c b/liveness.c
index eeff0f7..c9460de 100644
--- a/liveness.c
+++ b/liveness.c
@@ -12,22 +12,38 @@
#include "linearize.h"
#include "flow.h"
+
+static inline int trackable_pseudo(pseudo_t pseudo)
+{
+ return pseudo && (pseudo->type == PSEUDO_REG || pseudo->type == PSEUDO_ARG);
+}
+
static void phi_defines(struct instruction * phi_node, pseudo_t target,
- void (*defines)(struct basic_block *, struct instruction *, pseudo_t))
+ void (*defines)(struct basic_block *, struct instruction *, pseudo_t),
+ unsigned long generation)
{
pseudo_t phi;
FOR_EACH_PTR(phi_node->phi_list, phi) {
- struct instruction *def;
if (phi == VOID)
continue;
- def = phi->def;
- if (!def || !def->bb)
- continue;
- if (def->opcode == OP_PHI) {
- phi_defines(def, target, defines);
+ if (!phi->def || !phi->def->bb)
continue;
+
+ /*
+ * In case of "(PHISOURCE->PHI->)+ PHISOURCE->PHI" chain, move
+ * "defines" information upstream to the BB of a very first PHISOURCE
+ * (recursion guarded using "generation" marking of PHI insn BBs).
+ */
+ pseudo_t src_pseudo = phi->def->phi_src;
+ if (trackable_pseudo(src_pseudo) && src_pseudo->def->opcode == OP_PHI) {
+ phi_node->bb->generation = generation;
+ if (src_pseudo->def->bb->generation != generation) {
+ phi_defines(src_pseudo->def, target, defines, generation);
+ continue;
+ }
}
- defines(def->bb, phi->def, target);
+
+ defines(phi->def->bb, phi->def, target);
} END_FOR_EACH_PTR(phi);
}
@@ -103,7 +119,7 @@ static void track_instruction_usage(struct basic_block *bb, struct instruction *
/* Other */
case OP_PHI:
/* Phi-nodes are "backwards" nodes. Their def doesn't matter */
- phi_defines(insn, insn->target, def);
+ phi_defines(insn, insn->target, def, ++bb_generation);
break;
case OP_PHISOURCE:
@@ -179,11 +195,6 @@ static void add_pseudo_exclusive(struct pseudo_list **list, pseudo_t pseudo)
}
}
-static inline int trackable_pseudo(pseudo_t pseudo)
-{
- return pseudo && (pseudo->type == PSEUDO_REG || pseudo->type == PSEUDO_ARG);
-}
-
static void insn_uses(struct basic_block *bb, struct instruction *insn, pseudo_t pseudo)
{
if (trackable_pseudo(pseudo)) {
--
1.7.1
--
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