From f3391dde28a8ab2a6652cd43c7f58cafa04a5861 Mon Sep 17 00:00:00 2001
From: Michael Forney <mforney@mforney.org>
Date: Mon, 18 Oct 2021 10:49:24 -0700
Subject: expr: Make sure __builtin_va_end argument is evaluated for
 side-effects

---
 expr.c                   | 3 +--
 qbe.c                    | 3 ---
 test/varargs+riscv64.qbe | 6 ++++--
 3 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/expr.c b/expr.c
index 19dd012..0da1d43 100644
--- a/expr.c
+++ b/expr.c
@@ -668,8 +668,7 @@ builtinfunc(struct scope *s, enum builtinkind kind)
 		e = assignexpr(s);
 		if (!typesame(e->type, typeadjvalist))
 			error(&tok.loc, "va_end argument must have type va_list");
-		e = mkexpr(EXPRBUILTIN, &typevoid, NULL);
-		e->builtin.kind = BUILTINVAEND;
+		e = exprconvert(e, &typevoid);
 		break;
 	case BUILTINVASTART:
 		e = mkexpr(EXPRBUILTIN, &typevoid, assignexpr(s));
diff --git a/qbe.c b/qbe.c
index d40029a..f9a6f08 100644
--- a/qbe.c
+++ b/qbe.c
@@ -937,9 +937,6 @@ funcexpr(struct func *f, struct expr *e)
 				error(&tok.loc, "va_arg with non-scalar type is not yet supported");
 			l = funcexpr(f, e->base);
 			return funcinst(f, IVAARG, qbetype(e->type).base, l, NULL);
-		case BUILTINVAEND:
-			/* no-op */
-			break;
 		case BUILTINALLOCA:
 			l = funcexpr(f, e->base);
 			return funcinst(f, IALLOC16, ptrclass, l, NULL);
diff --git a/test/varargs+riscv64.qbe b/test/varargs+riscv64.qbe
index a918014..48638bb 100644
--- a/test/varargs+riscv64.qbe
+++ b/test/varargs+riscv64.qbe
@@ -22,8 +22,9 @@ function w $f2(w %.1, ...) {
 	%.6 =l loadl %.4
 	%.7 =w call $f1(w %.5, l %.6)
 	storew %.7, %.3
-	%.8 =w loadw %.3
-	ret %.8
+	%.8 =l loadl %.4
+	%.9 =w loadw %.3
+	ret %.9
 }
 export
 function $f3(w %.1, ...) {
@@ -45,5 +46,6 @@ function $f3(w %.1, ...) {
 	storew %.9, %.2
 	jmp @while_cond.7
 @while_join.9
+	%.10 =l loadl %.3
 	ret
 }
-- 
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