Compare instructions with both operands sign or zero-extended
from the same original size are equivalent to a compare of
the original values. If the values were zero-extended, a signed
compare becomes an unsigned one.
Simplify away the sign/zero-extensions.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
simplify.c | 52 ++++++++++++++++++++++++++------
validation/optim/cmp-sext-sext.c | 1 -
validation/optim/cmp-zext-zext.c | 1 -
3 files changed, 42 insertions(+), 12 deletions(-)
diff --git a/simplify.c b/simplify.c
index 7538c9393b41..d56d4c89a078 100644
--- a/simplify.c
+++ b/simplify.c
@@ -422,6 +422,22 @@ static inline bool is_signed_constant(long long val, unsigned osize, unsigned ns
return bits_extend(val, osize, 1) == bits_extend(val, nsize, 1);
}
+///
+// is @src generated by an instruction with the given opcode and size?
+static inline pseudo_t is_same_op(pseudo_t src, int op, unsigned osize)
+{
+ struct instruction *def;
+
+ if (src->type != PSEUDO_REG)
+ return NULL;
+ def = src->def;
+ if (def->opcode != op)
+ return NULL;
+ if (def->orig_type->bit_size != osize)
+ return NULL;
+ return def->src;
+}
+
///
// replace the operand of an instruction
// @insn: the instruction
@@ -1570,6 +1586,30 @@ static int simplify_sub(struct instruction *insn)
return 0;
}
+static int simplify_compare(struct instruction *insn)
+{
+ pseudo_t src1 = insn->src1;
+ pseudo_t src2 = insn->src2;
+ struct instruction *def;
+ unsigned int osize;
+ pseudo_t src;
+
+ switch (DEF_OPCODE(def, src1)) {
+ case OP_SEXT: case OP_ZEXT:
+ osize = def->orig_type->bit_size;
+ if ((src = is_same_op(src2, def->opcode, osize))) {
+ const struct opcode_table *op = &opcode_table[insn->opcode];
+ if ((def->opcode == OP_ZEXT) && (op->flags & OPF_SIGNED))
+ insn->opcode = op->sign;
+ insn->itype = def->orig_type;
+ replace_pseudo(insn, &insn->src1, def->src);
+ return replace_pseudo(insn, &insn->src2, src);
+ }
+ break;
+ }
+ return 0;
+}
+
static int simplify_constant_unop(struct instruction *insn)
{
long long val = insn->src1->value;
@@ -2083,17 +2123,9 @@ int simplify_instruction(struct instruction *insn)
case OP_DIVS:
case OP_MODU:
case OP_MODS:
- case OP_SET_EQ:
- case OP_SET_NE:
- case OP_SET_LE:
- case OP_SET_GE:
- case OP_SET_LT:
- case OP_SET_GT:
- case OP_SET_B:
- case OP_SET_A:
- case OP_SET_BE:
- case OP_SET_AE:
break;
+ case OP_BINCMP ... OP_BINCMP_END:
+ return simplify_compare(insn);
case OP_LOAD:
case OP_STORE:
return simplify_memop(insn);
diff --git a/validation/optim/cmp-sext-sext.c b/validation/optim/cmp-sext-sext.c
index ba6ed54e940c..3bd22fb738ca 100644
--- a/validation/optim/cmp-sext-sext.c
+++ b/validation/optim/cmp-sext-sext.c
@@ -11,7 +11,6 @@ _Bool cmpu_sext_sext(ARGS(INT32)) { return TEST(UINT64, UINT32, a, < , b); }
/*
* check-name: cmp-sext-sext
* check-command: test-linearize -Wno-decl $file
- * check-known-to-fail
*
* check-output-ignore
* check-output-returns: 1
diff --git a/validation/optim/cmp-zext-zext.c b/validation/optim/cmp-zext-zext.c
index 9f188297e214..88f9078f9480 100644
--- a/validation/optim/cmp-zext-zext.c
+++ b/validation/optim/cmp-zext-zext.c
@@ -11,7 +11,6 @@ _Bool cmpu_zext_zext(ARGS(UINT32)) { return TEST(UINT64, UINT32, a, < , b); }
/*
* check-name: cmp-zext-zext
* check-command: test-linearize -Wno-decl $file
- * check-known-to-fail
*
* check-output-ignore
* check-output-returns: 1
--
2.29.2
