Skip unnecessary conversion to bool for logical and conditional expressions

As in ede6a5c9, if an expression is used only to control a jnz, we
don't need to convert it to a 0 or 1 value. QBE ignores the upper
32-bits of the argument to jnz, so the conversion is still needed
for pointer, long, and floating point types (including float since
-0 has non-zero bit representation).

11 files changed, 213 insertions, 59 deletions

diff --git a/cc.h b/cc.h
index 41f7d90..49a3fd0 100644
--- a/cc.h
+++ b/cc.h
@@ -527,7 +527,7 @@ struct type *functype(struct func *);
 void funclabel(struct func *, struct block *);
 struct value *funcexpr(struct func *, struct expr *);
 void funcjmp(struct func *, struct block *);
-void funcjnz(struct func *, struct value *, struct block *, struct block *);
+void funcjnz(struct func *, struct value *, struct type *, struct block *, struct block *);
 void funcret(struct func *, struct value *);
 struct gotolabel *funcgoto(struct func *, char *);
 void funcswitch(struct func *, struct value *, struct switchcases *, struct block *);
diff --git a/expr.c b/expr.c
index 114aa5a..e2fbe0b 100644
--- a/expr.c
+++ b/expr.c
@@ -204,8 +204,6 @@ mkbinaryexpr(struct location *loc, enum tokenkind op, struct expr *l, struct exp
 			error(loc, "left operand of '%s' operator must be scalar", tokstr[op]);
 		if (!(rp & PROPSCALAR))
 			error(loc, "right operand of '%s' operator must be scalar", tokstr[op]);
-		l = exprconvert(l, &typebool);
-		r = exprconvert(r, &typebool);
 		t = &typeint;
 		break;
 	case TEQL:
@@ -1023,7 +1021,7 @@ condexpr(struct scope *s)
 	if (!consume(TQUESTION))
 		return r;
 	e = mkexpr(EXPRCOND, NULL);
-	e->base = exprconvert(r, &typebool);
+	e->base = r;
 	e->cond.t = expr(s);
 	expect(TCOLON, "in conditional expression");
 	e->cond.f = condexpr(s);
diff --git a/qbe.c b/qbe.c
index df6a74d..f6ac39b 100644
--- a/qbe.c
+++ b/qbe.c
@@ -405,7 +405,7 @@ utof(struct func *f, int dst, int src, struct value *v)
 	join->phi.blk[1] = mkblock("utof_big");
 
 	big = funcinst(f, ICSLTL, 'w', v, mkintconst(0));
-	funcjnz(f, big, join->phi.blk[1], join->phi.blk[0]);
+	funcjnz(f, big, NULL, join->phi.blk[1], join->phi.blk[0]);
 
 	funclabel(f, join->phi.blk[0]);
 	join->phi.val[0] = funcinst(f, ISLTOF, dst, v, NULL);
@@ -442,7 +442,7 @@ ftou(struct func *f, int dst, int src, struct value *v)
 	maxint = mkintconst(1ull<<63);
 
 	big = funcinst(f, src == 's' ? ICGES : ICGED, 'w', v, maxflt);
-	funcjnz(f, big, join->phi.blk[1], join->phi.blk[0]);
+	funcjnz(f, big, NULL, join->phi.blk[1], join->phi.blk[0]);
 
 	funclabel(f, join->phi.blk[0]);
 	join->phi.val[0] = funcinst(f, op, dst, v, NULL);
@@ -616,16 +616,26 @@ funcjmp(struct func *f, struct block *l)
 }
 
 void
-funcjnz(struct func *f, struct value *v, struct block *l1, struct block *l2)
+funcjnz(struct func *f, struct value *v, struct type *t, struct block *l1, struct block *l2)
 {
 	struct block *b = f->end;
 
-	if (!b->jump.kind) {
-		b->jump.kind = JUMP_JNZ;
-		b->jump.arg = v;
-		b->jump.blk[0] = l1;
-		b->jump.blk[1] = l2;
+	if (b->jump.kind)
+		return;
+	if (t) {
+		assert(t->prop & PROPSCALAR);
+		/*
+		Ideally we would just do this conversion unconditionally,
+		but QBE is not currently able to optimize the conversion
+		away for int.
+		*/
+		if (t->prop & PROPFLOAT || t->size > 4)
+			v = convert(f, &typebool, t, v);
 	}
+	b->jump.kind = JUMP_JNZ;
+	b->jump.arg = v;
+	b->jump.blk[0] = l1;
+	b->jump.blk[1] = l2;
 }
 
 void
@@ -786,11 +796,14 @@ funcexpr(struct func *f, struct expr *e)
 		if (e->op == TLOR || e->op == TLAND) {
 			b[0] = mkblock("logic_right");
 			b[1] = mkblock("logic_join");
-			if (e->op == TLOR)
-				funcjnz(f, l, b[1], b[0]);
-			else
-				funcjnz(f, l, b[0], b[1]);
-			b[1]->phi.val[0] = l;
+			t = e->binary.l->type;
+			if (e->op == TLOR) {
+				funcjnz(f, l, t, b[1], b[0]);
+				b[1]->phi.val[0] = mkintconst(1);
+			} else {
+				funcjnz(f, l, t, b[0], b[1]);
+				b[1]->phi.val[0] = mkintconst(0);
+			}
 			b[1]->phi.blk[0] = f->end;
 			funclabel(f, b[0]);
 			r = funcexpr(f, e->binary.r);
@@ -882,7 +895,7 @@ funcexpr(struct func *f, struct expr *e)
 		b[2] = mkblock("cond_join");
 
 		v = funcexpr(f, e->base);
-		funcjnz(f, v, b[0], b[1]);
+		funcjnz(f, v, e->base->type, b[0], b[1]);
 
 		funclabel(f, b[0]);
 		b[2]->phi.val[0] = funcexpr(f, e->cond.t);
@@ -1030,10 +1043,10 @@ casesearch(struct func *f, int class, struct value *v, struct switchcase *c, str
 	// XXX: linear search if c->node.height < 4
 	key = mkintconst(c->node.key);
 	res = funcinst(f, class == 'w' ? ICEQW : ICEQL, 'w', v, key);
-	funcjnz(f, res, c->body, label[0]);
+	funcjnz(f, res, NULL, c->body, label[0]);
 	funclabel(f, label[0]);
 	res = funcinst(f, class == 'w' ? ICULTW : ICULTL, 'w', v, key);
-	funcjnz(f, res, label[1], label[2]);
+	funcjnz(f, res, NULL, label[1], label[2]);
 	funclabel(f, label[1]);
 	casesearch(f, class, v, c->node.child[0], defaultlabel);
 	funclabel(f, label[2]);
diff --git a/stmt.c b/stmt.c
index 0a5c118..a997290 100644
--- a/stmt.c
+++ b/stmt.c
@@ -24,27 +24,6 @@ gotolabel(struct func *f)
 	return true;
 }
 
-/* controlling expression of loops and if-statements */
-static struct expr *
-ctrlexpr(struct scope *s)
-{
-	struct expr *e;
-	struct type *t;
-
-	e = expr(s);
-	t = e->type;
-	if (!(t->prop & PROPSCALAR))
-		error(&tok.loc, "controlling expression must have scalar type");
-	/*
-	Ideally we would just do this conversion unconditionally,
-	but QBE is not currently able to optimize the conversion
-	away for int.
-	*/
-	if (t->prop & PROPFLOAT || t->size > 4)
-		e = exprconvert(e, &typebool);
-	return e;
-}
-
 /* 6.8 Statements and blocks */
 void
 stmt(struct func *f, struct scope *s)
@@ -112,14 +91,17 @@ stmt(struct func *f, struct scope *s)
 		next();
 		s = mkscope(s);
 		expect(TLPAREN, "after 'if'");
-		e = ctrlexpr(s);
+		e = expr(s);
+		t = e->type;
+		if (!(t->prop & PROPSCALAR))
+			error(&tok.loc, "controlling expression of if statement must have scalar type");
 		v = funcexpr(f, e);
 		delexpr(e);
 		expect(TRPAREN, "after expression");
 
 		label[0] = mkblock("if_true");
 		label[1] = mkblock("if_false");
-		funcjnz(f, v, label[0], label[1]);
+		funcjnz(f, v, t, label[0], label[1]);
 
 		funclabel(f, label[0]);
 		s = mkscope(s);
@@ -179,7 +161,10 @@ stmt(struct func *f, struct scope *s)
 		next();
 		s = mkscope(s);
 		expect(TLPAREN, "after 'while'");
-		e = ctrlexpr(s);
+		e = expr(s);
+		t = e->type;
+		if (!(t->prop & PROPSCALAR))
+			error(&tok.loc, "controlling expression of loop must have scalar type");
 		expect(TRPAREN, "after expression");
 
 		label[0] = mkblock("while_cond");
@@ -188,7 +173,7 @@ stmt(struct func *f, struct scope *s)
 
 		funclabel(f, label[0]);
 		v = funcexpr(f, e);
-		funcjnz(f, v, label[1], label[2]);
+		funcjnz(f, v, t, label[1], label[2]);
 		funclabel(f, label[1]);
 		s = mkscope(s);
 		s->continuelabel = label[0];
@@ -217,11 +202,14 @@ stmt(struct func *f, struct scope *s)
 		expect(TWHILE, "after 'do' statement");
 		expect(TLPAREN, "after 'while'");
 		funclabel(f, label[1]);
-		e = ctrlexpr(s);
+		e = expr(s);
+		t = e->type;
+		if (!(t->prop & PROPSCALAR))
+			error(&tok.loc, "controlling expression of loop must have scalar type");
 		expect(TRPAREN, "after expression");
 
 		v = funcexpr(f, e);
-		funcjnz(f, v, label[0], label[2]);  // XXX: compare to 0
+		funcjnz(f, v, t, label[0], label[2]);  // XXX: compare to 0
 		funclabel(f, label[2]);
 		s = delscope(s);
 		expect(TSEMICOLON, "after 'do' statement");
@@ -246,9 +234,12 @@ stmt(struct func *f, struct scope *s)
 
 		funclabel(f, label[0]);
 		if (tok.kind != TSEMICOLON) {
-			e = ctrlexpr(s);
+			e = expr(s);
+			t = e->type;
+			if (!(t->prop & PROPSCALAR))
+				error(&tok.loc, "controlling expression of loop must have scalar type");
 			v = funcexpr(f, e);
-			funcjnz(f, v, label[1], label[3]);
+			funcjnz(f, v, t, label[1], label[3]);
 			delexpr(e);
 		}
 		expect(TSEMICOLON, NULL);
diff --git a/test/conditional-compound-literal.qbe b/test/conditional-compound-literal.qbe
index 57358e6..739eea4 100644
--- a/test/conditional-compound-literal.qbe
+++ b/test/conditional-compound-literal.qbe
@@ -3,20 +3,19 @@ function w $main() {
 @start.1
 	%.1 =l alloc4 4
 	%.2 =l alloc8 8
-	%.4 =l alloc4 4
+	%.3 =l alloc4 4
 @body.2
 	storew 0, %.1
-	%.3 =w cnew 0, 0
-	jnz %.3, @cond_true.3, @cond_false.4
+	jnz 0, @cond_true.3, @cond_false.4
 @cond_true.3
 	jmp @cond_join.5
 @cond_false.4
-	%.5 =w loadw %.1
-	storew %.5, %.4
+	%.4 =w loadw %.1
+	storew %.4, %.3
 @cond_join.5
-	%.6 =l phi @cond_true.3 0, @cond_false.4 %.4
-	storel %.6, %.2
-	%.7 =l loadl %.2
-	%.8 =w loadw %.7
-	ret %.8
+	%.5 =l phi @cond_true.3 0, @cond_false.4 %.3
+	storel %.5, %.2
+	%.6 =l loadl %.2
+	%.7 =w loadw %.6
+	ret %.7
 }
diff --git a/test/conditional.c b/test/conditional.c
new file mode 100644
index 0000000..1c03ee5
--- /dev/null
+++ b/test/conditional.c
@@ -0,0 +1,11 @@
+int i;
+float f;
+void *p;
+int main(void) {
+	if (i ? 1 : 0)
+		return 1;
+	if (f ? 1 : 0)
+		return 1;
+	if (p ? 1 : 0)
+		return 1;
+}
diff --git a/test/conditional.qbe b/test/conditional.qbe
new file mode 100644
index 0000000..f4d6f28
--- /dev/null
+++ b/test/conditional.qbe
@@ -0,0 +1,44 @@
+export
+function w $main() {
+@start.1
+@body.2
+	%.1 =w loadw $i
+	jnz %.1, @cond_true.3, @cond_false.4
+@cond_true.3
+	jmp @cond_join.5
+@cond_false.4
+@cond_join.5
+	%.2 =w phi @cond_true.3 1, @cond_false.4 0
+	jnz %.2, @if_true.6, @if_false.7
+@if_true.6
+	ret 1
+@if_false.7
+	%.3 =s loads $f
+	%.4 =w cnes %.3, s_0
+	jnz %.4, @cond_true.8, @cond_false.9
+@cond_true.8
+	jmp @cond_join.10
+@cond_false.9
+@cond_join.10
+	%.5 =w phi @cond_true.8 1, @cond_false.9 0
+	jnz %.5, @if_true.11, @if_false.12
+@if_true.11
+	ret 1
+@if_false.12
+	%.6 =l loadl $p
+	%.7 =w cnel %.6, 0
+	jnz %.7, @cond_true.13, @cond_false.14
+@cond_true.13
+	jmp @cond_join.15
+@cond_false.14
+@cond_join.15
+	%.8 =w phi @cond_true.13 1, @cond_false.14 0
+	jnz %.8, @if_true.16, @if_false.17
+@if_true.16
+	ret 1
+@if_false.17
+	ret 0
+}
+export data $i = align 4 { z 4 }
+export data $f = align 4 { z 4 }
+export data $p = align 8 { z 8 }
diff --git a/test/logical-and.c b/test/logical-and.c
new file mode 100644
index 0000000..34b4867
--- /dev/null
+++ b/test/logical-and.c
@@ -0,0 +1,11 @@
+int i;
+float f;
+void *p;
+int main(void) {
+	if (i && 1)
+		return 1;
+	if (f && 1)
+		return 1;
+	if (p && 1)
+		return 1;
+}
diff --git a/test/logical-and.qbe b/test/logical-and.qbe
new file mode 100644
index 0000000..21fd79a
--- /dev/null
+++ b/test/logical-and.qbe
@@ -0,0 +1,38 @@
+export
+function w $main() {
+@start.1
+@body.2
+	%.1 =w loadw $i
+	jnz %.1, @logic_right.3, @logic_join.4
+@logic_right.3
+@logic_join.4
+	%.2 =w phi @body.2 0, @logic_right.3 1
+	jnz %.2, @if_true.5, @if_false.6
+@if_true.5
+	ret 1
+@if_false.6
+	%.3 =s loads $f
+	%.4 =w cnes %.3, s_0
+	jnz %.4, @logic_right.7, @logic_join.8
+@logic_right.7
+@logic_join.8
+	%.5 =w phi @if_false.6 0, @logic_right.7 1
+	jnz %.5, @if_true.9, @if_false.10
+@if_true.9
+	ret 1
+@if_false.10
+	%.6 =l loadl $p
+	%.7 =w cnel %.6, 0
+	jnz %.7, @logic_right.11, @logic_join.12
+@logic_right.11
+@logic_join.12
+	%.8 =w phi @if_false.10 0, @logic_right.11 1
+	jnz %.8, @if_true.13, @if_false.14
+@if_true.13
+	ret 1
+@if_false.14
+	ret 0
+}
+export data $i = align 4 { z 4 }
+export data $f = align 4 { z 4 }
+export data $p = align 8 { z 8 }
diff --git a/test/logical-or.c b/test/logical-or.c
new file mode 100644
index 0000000..2a0485c
--- /dev/null
+++ b/test/logical-or.c
@@ -0,0 +1,11 @@
+int i;
+float f;
+void *p;
+int main(void) {
+	if (i || 0)
+		return 1;
+	if (f || 0)
+		return 1;
+	if (p || 0)
+		return 1;
+}
diff --git a/test/logical-or.qbe b/test/logical-or.qbe
new file mode 100644
index 0000000..e1025c9
--- /dev/null
+++ b/test/logical-or.qbe
@@ -0,0 +1,38 @@
+export
+function w $main() {
+@start.1
+@body.2
+	%.1 =w loadw $i
+	jnz %.1, @logic_join.4, @logic_right.3
+@logic_right.3
+@logic_join.4
+	%.2 =w phi @body.2 1, @logic_right.3 0
+	jnz %.2, @if_true.5, @if_false.6
+@if_true.5
+	ret 1
+@if_false.6
+	%.3 =s loads $f
+	%.4 =w cnes %.3, s_0
+	jnz %.4, @logic_join.8, @logic_right.7
+@logic_right.7
+@logic_join.8
+	%.5 =w phi @if_false.6 1, @logic_right.7 0
+	jnz %.5, @if_true.9, @if_false.10
+@if_true.9
+	ret 1
+@if_false.10
+	%.6 =l loadl $p
+	%.7 =w cnel %.6, 0
+	jnz %.7, @logic_join.12, @logic_right.11
+@logic_right.11
+@logic_join.12
+	%.8 =w phi @if_false.10 1, @logic_right.11 0
+	jnz %.8, @if_true.13, @if_false.14
+@if_true.13
+	ret 1
+@if_false.14
+	ret 0
+}
+export data $i = align 4 { z 4 }
+export data $f = align 4 { z 4 }
+export data $p = align 8 { z 8 }