From a877ba986b4c5b24ee07d59b3001d45fd5b3f834 Mon Sep 17 00:00:00 2001
From: Quentin Carbonneaux <quentin@c9x.me>
Date: Thu, 21 Feb 2019 14:42:01 +0100
Subject: fix amd64 addressing mode matcher

The numberer made some arranging choices when
numbering arguments of an instruction, but these
decisions were ignored when matching.  The fix
is to reconcile numbering and matching.
---
 amd64/isel.c | 35 +++++++++++++++--------------------
 1 file changed, 15 insertions(+), 20 deletions(-)

(limited to 'amd64')

diff --git a/amd64/isel.c b/amd64/isel.c
index 2519ae5..6aea850 100644
--- a/amd64/isel.c
+++ b/amd64/isel.c
@@ -25,7 +25,7 @@ struct ANum {
 	Ins *i;
 };
 
-static void amatch(Addr *, Ref, ANum *, Fn *, int);
+static int amatch(Addr *, Ref, int, ANum *, Fn *);
 
 static int
 noimm(Ref r, Fn *fn)
@@ -131,8 +131,8 @@ seladdr(Ref *r, ANum *an, Fn *fn)
 
 	r0 = *r;
 	if (rtype(r0) == RTmp) {
-		amatch(&a, r0, an, fn, 1);
-		if (req(a.base, r0))
+		memset(&a, 0, sizeof a);
+		if (!amatch(&a, r0, an[r0.val].n, an, fn))
 			return;
 		if (a.offset.type == CAddr)
 		if (!req(a.base, R)) {
@@ -488,18 +488,16 @@ anumber(ANum *ai, Blk *b, Con *con)
 	}
 }
 
-static void
-amatch(Addr *a, Ref r, ANum *ai, Fn *fn, int top)
+static int
+amatch(Addr *a, Ref r, int n, ANum *ai, Fn *fn)
 {
 	Ins *i;
 	int nl, nr, t, s;
 	Ref al, ar;
 
-	if (top)
-		memset(a, 0, sizeof *a);
 	if (rtype(r) == RCon) {
 		addcon(&a->offset, &fn->con[r.val]);
-		return;
+		return 1;
 	}
 	assert(rtype(r) == RTmp);
 	i = ai[r.val].i;
@@ -515,14 +513,11 @@ amatch(Addr *a, Ref r, ANum *ai, Fn *fn, int top)
 			ar = i->arg[1];
 		}
 	}
-	switch (ai[r.val].n) {
+	switch (n) {
 	case 3: /* s * i */
-		if (!top) {
-			a->index = al;
-			a->scale = fn->con[ar.val].bits.i;
-		} else
-			a->base = r;
-		break;
+		a->index = al;
+		a->scale = fn->con[ar.val].bits.i;
+		return 0;
 	case 4: /* b + s * i */
 		switch (nr) {
 		case 0:
@@ -534,7 +529,7 @@ amatch(Addr *a, Ref r, ANum *ai, Fn *fn, int top)
 			a->scale = 1;
 			break;
 		case 3:
-			amatch(a, ar, ai, fn, 0);
+			amatch(a, ar, nr, ai, fn);
 			break;
 		}
 		r = al;
@@ -544,14 +539,14 @@ amatch(Addr *a, Ref r, ANum *ai, Fn *fn, int top)
 		if (s != -1)
 			r = SLOT(s);
 		a->base = r;
-		break;
+		return n || s != -1;
 	case 2: /* constants */
 	case 5: /* o + s * i */
 	case 6: /* o + b */
 	case 7: /* o + b + s * i */
-		amatch(a, ar, ai, fn, 0);
-		amatch(a, al, ai, fn, 0);
-		break;
+		amatch(a, ar, nr, ai, fn);
+		amatch(a, al, nl, ai, fn);
+		return 1;
 	default:
 		die("unreachable");
 	}
-- 
cgit 1.4.1