5c, 6c, 7c, 8c, kc, qc, vc: use explicit gmove(... , nn) in cgen() for result of OAS*, OPREINC, OPOSTINC

The expression value of the assignment operation was
returned implicitely by relying on regalloc() on the
right hand side "nod" borrowing the register from nn.

But this only works if nn is a register.

In case of 6c, it can also be a ONAME from a .safe
rathole returned by regsalloc().

This change adds explicit gmove() calls to assign the
expression value. Note that gmove() checks if source
and destination are the same register so it wont emit
redundant move operations in the common case.

The same is applied also to OPREINC and OPOSTINC operations.

7 files changed, 52 insertions, 14 deletions

diff --git a/sys/src/cmd/5c/cgen.c b/sys/src/cmd/5c/cgen.c
index dae6e1872..fdddfa8e9 100644
--- a/sys/src/cmd/5c/cgen.c
+++ b/sys/src/cmd/5c/cgen.c
@@ -113,6 +113,8 @@ cgenrel(Node *n, Node *nn, int inrel)
 			reglcgen(&nod1, l, Z);
 		}
 		gmove(&nod, &nod1);
+		if(nn != Z)
+			gmove(&nod, nn);
 		regfree(&nod);
 		regfree(&nod1);
 		break;
@@ -251,7 +253,8 @@ cgenrel(Node *n, Node *nn, int inrel)
 			gopcode(OAS, &nod2, Z, &nod);
 			gopcode(o, r, Z, &nod);
 			gopcode(OAS, &nod, Z, &nod2);
-	
+			if(nn != Z)
+				gmove(&nod, nn);
 			regfree(&nod);
 			if(l->addable < INDEXED)
 				regfree(&nod2);
@@ -472,6 +475,8 @@ cgenrel(Node *n, Node *nn, int inrel)
 
 		regalloc(&nod, l, nn);
 		gopcode(OAS, &nod2, Z, &nod);
+		if(nn != Z)
+			gmove(&nod, nn);
 		regalloc(&nod1, l, Z);
 		if(typefd[l->type->etype]) {
 			regalloc(&nod3, l, Z);
@@ -524,9 +529,11 @@ cgenrel(Node *n, Node *nn, int inrel)
 		} else
 			gopcode(OADD, nodconst(v), Z, &nod);
 		gopcode(OAS, &nod, Z, &nod2);
-		if(nn && l->op == ONAME)	/* in x=++i, emit USED(i) */
-			gins(ANOP, l, Z);
-
+		if(nn != Z){
+			gmove(&nod, nn);
+			if(l->op == ONAME)	/* in x=++i, emit USED(i) */
+				gins(ANOP, l, Z);
+		}
 		regfree(&nod);
 		if(l->addable < INDEXED)
 			regfree(&nod2);
diff --git a/sys/src/cmd/6c/cgen.c b/sys/src/cmd/6c/cgen.c
index d86eed225..05b285946 100644
--- a/sys/src/cmd/6c/cgen.c
+++ b/sys/src/cmd/6c/cgen.c
@@ -112,6 +112,8 @@ cgen(Node *n, Node *nn)
 		if(l->complex >= r->complex) {
 			if(l->op == OINDEX && immconst(r)) {
 				gmove(r, l);
+				if(nn != Z)
+					gmove(r, nn);
 				break;
 			}
 			reglcgen(&nod1, l, Z);
@@ -130,6 +132,8 @@ cgen(Node *n, Node *nn)
 			reglcgen(&nod1, l, Z);
 		}
 		gmove(&nod, &nod1);
+		if(nn != Z)
+			gmove(&nod, nn);
 		regfree(&nod);
 		regfree(&nod1);
 		break;
diff --git a/sys/src/cmd/7c/cgen.c b/sys/src/cmd/7c/cgen.c
index bed0087f9..3cb84a65c 100644
--- a/sys/src/cmd/7c/cgen.c
+++ b/sys/src/cmd/7c/cgen.c
@@ -128,6 +128,8 @@ cgenrel(Node *n, Node *nn, int inrel)
 			reglcgen(&nod1, l, Z);
 		}
 		gmove(&nod, &nod1);
+		if(nn != Z)
+			gmove(&nod, nn);
 		regfree(&nod);
 		regfree(&nod1);
 		break;
@@ -267,7 +269,8 @@ cgenrel(Node *n, Node *nn, int inrel)
 			gopcode(OAS, &nod2, Z, &nod);
 			gopcode(o, r, Z, &nod);
 			gopcode(OAS, &nod, Z, &nod2);
-	
+			if(nn != Z)
+				gmove(&nod, nn);
 			regfree(&nod);
 			if(l->addable < INDEXED)
 				regfree(&nod2);
@@ -528,6 +531,8 @@ cgenrel(Node *n, Node *nn, int inrel)
 
 		regalloc(&nod, l, nn);
 		gopcode(OAS, &nod2, Z, &nod);
+		if(nn != Z)
+			gmove(&nod, nn);
 		regalloc(&nod1, l, Z);
 		if(typefd[l->type->etype]) {
 			regalloc(&nod3, l, Z);
@@ -580,9 +585,11 @@ cgenrel(Node *n, Node *nn, int inrel)
 		} else
 			gopcode(OADD, nodconst(v), Z, &nod);
 		gopcode(OAS, &nod, Z, &nod2);
-		if(nn && l->op == ONAME)	/* in x=++i, emit USED(i) */
-			gins(ANOP, l, Z);
-
+		if(nn != Z){
+			gmove(&nod, nn);
+			if(l->op == ONAME)	/* in x=++i, emit USED(i) */
+				gins(ANOP, l, Z);
+		}
 		regfree(&nod);
 		if(l->addable < INDEXED)
 			regfree(&nod2);
diff --git a/sys/src/cmd/8c/cgen.c b/sys/src/cmd/8c/cgen.c
index 0c26454e8..c1ec490d5 100644
--- a/sys/src/cmd/8c/cgen.c
+++ b/sys/src/cmd/8c/cgen.c
@@ -131,6 +131,8 @@ cgen(Node *n, Node *nn)
 		if(l->complex >= r->complex) {
 			if(l->op == OINDEX && r->op == OCONST) {
 				gmove(r, l);
+				if(nn != Z)
+					gmove(r, nn);
 				break;
 			}
 			reglcgen(&nod1, l, Z);
@@ -149,6 +151,8 @@ cgen(Node *n, Node *nn)
 			reglcgen(&nod1, l, Z);
 		}
 		gmove(&nod, &nod1);
+		if(nn != Z)
+			gmove(&nod, nn);
 		regfree(&nod);
 		regfree(&nod1);
 		break;
diff --git a/sys/src/cmd/kc/cgen.c b/sys/src/cmd/kc/cgen.c
index ad295177b..401812e60 100644
--- a/sys/src/cmd/kc/cgen.c
+++ b/sys/src/cmd/kc/cgen.c
@@ -107,6 +107,8 @@ cgen(Node *n, Node *nn)
 			reglcgen(&nod1, l, Z);
 		}
 		gmove(&nod, &nod1);
+		if(nn != Z)
+			gmove(&nod, nn);
 		regfree(&nod);
 		regfree(&nod1);
 		break;
@@ -423,6 +425,8 @@ cgen(Node *n, Node *nn)
 
 		regalloc(&nod, l, nn);
 		gopcode(OAS, &nod2, Z, &nod);
+		if(nn != Z)
+			gmove(&nod, nn);
 		regalloc(&nod1, l, Z);
 		if(typefd[l->type->etype]) {
 			regalloc(&nod3, l, Z);
@@ -475,9 +479,11 @@ cgen(Node *n, Node *nn)
 		} else
 			gopcode(OADD, nodconst(v), Z, &nod);
 		gopcode(OAS, &nod, Z, &nod2);
-		if(nn && l->op == ONAME)	/* in x=++i, emit USED(i) */
-			gins(ANOP, l, Z);
-
+		if(nn != Z){
+			gmove(&nod, nn);
+			if(l->op == ONAME)	/* in x=++i, emit USED(i) */
+				gins(ANOP, l, Z);
+		}
 		regfree(&nod);
 		if(l->addable < INDEXED)
 			regfree(&nod2);
diff --git a/sys/src/cmd/qc/cgen.c b/sys/src/cmd/qc/cgen.c
index b2391e3f8..6f09197d6 100644
--- a/sys/src/cmd/qc/cgen.c
+++ b/sys/src/cmd/qc/cgen.c
@@ -109,6 +109,8 @@ cgen(Node *n, Node *nn)
 				regalloc(&nod, r, nn);
 				cgen(r, &nod);
 				gmove(&nod, l);
+				if(nn != Z)
+					gmove(&nod, nn);
 				regfree(&nod);
 			} else
 				gmove(r, l);
@@ -131,6 +133,8 @@ cgen(Node *n, Node *nn)
 			reglcgen(&nod1, l, Z);
 		}
 		gmove(&nod, &nod1);
+		if(nn != Z)
+			gmove(&nod, nn);
 		regfree(&nod);
 		regfree(&nod1);
 		break;
diff --git a/sys/src/cmd/vc/cgen.c b/sys/src/cmd/vc/cgen.c
index 7b9ec4808..4c0cf61c1 100644
--- a/sys/src/cmd/vc/cgen.c
+++ b/sys/src/cmd/vc/cgen.c
@@ -107,6 +107,8 @@ cgen(Node *n, Node *nn)
 			reglcgen(&nod1, l, Z);
 		}
 		gmove(&nod, &nod1);
+		if(nn != Z)
+			gmove(&nod, nn);
 		regfree(&nod);
 		regfree(&nod1);
 		break;
@@ -425,6 +427,8 @@ cgen(Node *n, Node *nn)
 
 		regalloc(&nod, l, nn);
 		gopcode(OAS, &nod2, Z, &nod);
+		if(nn != Z)
+			gmove(&nod, nn);
 		regalloc(&nod1, l, Z);
 		if(typefd[l->type->etype]) {
 			regalloc(&nod3, l, Z);
@@ -477,9 +481,11 @@ cgen(Node *n, Node *nn)
 		} else
 			gopcode(OADD, nodconst(v), Z, &nod);
 		gopcode(OAS, &nod, Z, &nod2);
-		if(nn && l->op == ONAME)	/* in x=++i, emit USED(i) */
-			gins(ANOP, l, Z);
-
+		if(nn != Z) {
+			gmove(&nod, nn);
+			if(l->op == ONAME)	/* in x=++i, emit USED(i) */
+				gins(ANOP, l, Z);
+		}
 		regfree(&nod);
 		if(l->addable < INDEXED)
 			regfree(&nod2);