Now that cast instructions are more finely grained, it's
not needed to compare the original type of the casts,
only the original size can matter.
So, do not hash & compare the original types but only the
orignal sizes. This allow much more casts instructions to be
CSEed away.
Note: like noted in the code, even the original size shouldn't
matter as identical sources should implies identical
original sizes but this can't yet be guaranted.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
The patch is available for review & testing in the Git repository at:
git://github.com/lucvoo/sparse-dev.git cse-cast
before being promoted to the stable tree at:
git://github.com/lucvoo/sparse.git master
----------------------------------------------------------------
cse.c | 28 ++++++++++++++++------------
1 file changed, 16 insertions(+), 12 deletions(-)
diff --git a/cse.c b/cse.c
index 33cc40dc7..e69fc81fb 100644
--- a/cse.c
+++ b/cse.c
@@ -95,14 +95,12 @@ void cse_collect(struct instruction *insn)
case OP_TRUNC:
case OP_PTRCAST:
case OP_UTPTR: case OP_PTRTU:
- /*
- * This is crap! Many "orig_types" are the
- * same as far as casts go, we should generate
- * some kind of "type hash" that is identical
- * for identical casts
- */
- hash += hashval(insn->orig_type);
+ if (!insn->orig_type || insn->orig_type->bit_size < 0)
+ return;
hash += hashval(insn->src);
+
+ // Note: see corresponding line in insn_compare()
+ hash += hashval(insn->orig_type->bit_size);
break;
/* Other */
@@ -165,6 +163,7 @@ static int insn_compare(const void *_i1, const void *_i2)
{
const struct instruction *i1 = _i1;
const struct instruction *i2 = _i2;
+ int size1, size2;
int diff;
if (i1->opcode != i2->opcode)
@@ -243,13 +242,18 @@ static int insn_compare(const void *_i1, const void *_i2)
case OP_TRUNC:
case OP_PTRCAST:
case OP_UTPTR: case OP_PTRTU:
- /*
- * This is crap! See the comments on hashing.
- */
- if (i1->orig_type != i2->orig_type)
- return i1->orig_type < i2->orig_type ? -1 : 1;
if (i1->src != i2->src)
return i1->src < i2->src ? -1 : 1;
+
+ // Note: if it can be guaranted that identical ->src
+ // implies identical orig_type->bit_size, then this
+ // test and the hashing of the original size in
+ // cse_collect() are not needed.
+ // It must be generaly true but it isn't guaranted (yet).
+ size1 = i1->orig_type->bit_size;
+ size2 = i2->orig_type->bit_size;
+ if (size1 != size2)
+ return size1 < size2 ? -1 : 1;
break;
default:
--
2.18.0
--
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