Processing in the middle-end are much easier if undefined values
have been clearly identified. Once done, we can then make
choices like:
- always initialize them to zero
- allow arbitraly simplification,
- ...
Prepare for this by declaring a new type of pseudo: PSEUDO_UNDEF
somewhat similar to PSEUDO_VOID.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
linearize.c | 2 ++
linearize.h | 3 ++-
sparse-llvm.c | 4 ++++
3 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/linearize.c b/linearize.c
index 3a1bc74ed..aadecfc5d 100644
--- a/linearize.c
+++ b/linearize.c
@@ -155,6 +155,8 @@ const char *show_pseudo(pseudo_t pseudo)
if (pseudo->ident)
sprintf(buf+i, "(%s)", show_ident(pseudo->ident));
break;
+ case PSEUDO_UNDEF:
+ return "UNDEF";
default:
snprintf(buf, 64, "<bad pseudo type %d>", pseudo->type);
}
diff --git a/linearize.h b/linearize.h
index c03940eea..54fcf2a46 100644
--- a/linearize.h
+++ b/linearize.h
@@ -21,6 +21,7 @@ DECLARE_PTR_LIST(pseudo_user_list, struct pseudo_user);
enum pseudo_type {
PSEUDO_VOID,
+ PSEUDO_UNDEF,
PSEUDO_REG,
PSEUDO_SYM,
PSEUDO_VAL,
@@ -290,7 +291,7 @@ static inline void add_pseudo_user_ptr(struct pseudo_user *user, struct pseudo_u
static inline int has_use_list(pseudo_t p)
{
- return (p && p->type != PSEUDO_VOID && p->type != PSEUDO_VAL);
+ return (p && p->type != PSEUDO_VOID && p->type != PSEUDO_UNDEF && p->type != PSEUDO_VAL);
}
static inline struct pseudo_user *alloc_pseudo_user(struct instruction *insn, pseudo_t *pp)
diff --git a/sparse-llvm.c b/sparse-llvm.c
index 29fb65f15..f8d48d264 100644
--- a/sparse-llvm.c
+++ b/sparse-llvm.c
@@ -289,6 +289,7 @@ static void pseudo_name(pseudo_t pseudo, char *buf)
assert(0);
break;
case PSEUDO_VAL:
+ case PSEUDO_UNDEF:
assert(0);
break;
case PSEUDO_ARG: {
@@ -372,6 +373,9 @@ static LLVMValueRef pseudo_to_value(struct function *fn, struct instruction *ins
case PSEUDO_VOID:
result = NULL;
break;
+ case PSEUDO_UNDEF:
+ result = LLVMGetUndef(symbol_type(fn->module, insn->type));
+ break;
default:
assert(0);
}
--
2.14.0
--
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