[24/29] sssa: add PSEUDO_INDIR

Commit Message

Luc Van Oostenryck Aug. 16, 2017, 3:34 p.m. UTC

Simplification of trivial pseudos require to replace
a pseudo for another in all ptrmap. Since this could
be an annoying and relatively costly operation
if effectively done by looking after each pseudos,
this patch introduce a new type of pseudo used as a
a sort of a symlink for another one: PSEUDO_INDIR.

So the processing is almost for free and this indirection
has just to be done when looking after the corresponding var.

Signed-off-by: Luc Van Oostenryck <[e-mail]>
---
 linearize.c | 2 ++
 linearize.h | 2 ++
 ssa.c       | 2 ++
 3 files changed, 6 insertions(+)

Patch

diff --git a/linearize.c b/linearize.c
index 1630810d4..f47748b38 100644
--- a/linearize.c
+++ b/linearize.c
@@ -157,6 +157,8 @@  const char *show_pseudo(pseudo_t pseudo)
 		break;
 	case PSEUDO_UNDEF:
 		return "UNDEF";
+	case PSEUDO_INDIR:
+		return show_pseudo(pseudo->target);
 	default:
 		snprintf(buf, 64, "<bad pseudo type %d>", pseudo->type);
 	}
diff --git a/linearize.h b/linearize.h
index eba0323d0..3fdcd487c 100644
--- a/linearize.h
+++ b/linearize.h
@@ -29,6 +29,7 @@  enum pseudo_type {
 	PSEUDO_VAL,
 	PSEUDO_ARG,
 	PSEUDO_PHI,
+	PSEUDO_INDIR,
 };
 
 struct pseudo {
@@ -40,6 +41,7 @@  struct pseudo {
 		struct symbol *sym;
 		struct instruction *def;
 		long long value;
+		pseudo_t target;
 	};
 	void *priv;
 };
diff --git a/ssa.c b/ssa.c
index e50fae0cc..10279a602 100644
--- a/ssa.c
+++ b/ssa.c
@@ -73,6 +73,8 @@  pseudo_t load_var(struct basic_block *bb, struct symbol *var)
 	pseudo_t val = phi_map_lookup(var->phi_map, bb);
 	if (!val)
 		val = load_var_parents(bb, var);
+	while (val->type == PSEUDO_INDIR)
+		val = val->target;
 	return val;
 }