From 7ffff16e6745c267b77d23a047f6ca5f20ca71e7 Mon Sep 17 00:00:00 2001
From: Michael Forney <mforney@mforney.org>
Date: Mon, 25 Oct 2021 15:00:48 -0700
Subject: decl: Allow alignment > 16 of globals and struct members

---
 decl.c                  | 6 ++++--
 test/alignas-local.c    | 4 ++++
 test/alignas-local.qbe  | 9 +++++++++
 test/alignas-member.c   | 4 ++++
 test/alignas-member.qbe | 1 +
 test/alignas.c          | 2 +-
 test/alignas.qbe        | 2 +-
 7 files changed, 24 insertions(+), 4 deletions(-)
 create mode 100644 test/alignas-local.c
 create mode 100644 test/alignas-local.qbe
 create mode 100644 test/alignas-member.c
 create mode 100644 test/alignas-member.qbe

diff --git a/decl.c b/decl.c
index c673463..50fe1c6 100644
--- a/decl.c
+++ b/decl.c
@@ -379,7 +379,7 @@ declspecs(struct scope *s, enum storageclass *sc, enum funcspec *fs, int *align)
 				*align = other->align;
 			} else {
 				i = intconstexpr(s, false);
-				if (i & (i - 1) || i > 16)
+				if (i & (i - 1))
 					error(&tok.loc, "invalid alignment: %d", i);
 				if (i)
 					*align = (int)i;
@@ -960,8 +960,10 @@ decl(struct scope *s, struct func *f)
 			if (init || d->linkage == LINKNONE) {
 				if (d->linkage != LINKNONE || sc & SCSTATIC)
 					emitdata(d, init);
-				else
+				else if (d->align <= 16)
 					funcinit(f, d, init);
+				else
+					error(&tok.loc, "unsupported alignment %d for object with automatic storage duration", d->align);
 				d->defined = true;
 				if (d->tentative.next)
 					listremove(&d->tentative);
diff --git a/test/alignas-local.c b/test/alignas-local.c
new file mode 100644
index 0000000..e1a8667
--- /dev/null
+++ b/test/alignas-local.c
@@ -0,0 +1,4 @@
+int main(void) {
+	_Alignas(16) char x;
+	return (unsigned long)&x % 16;
+}
diff --git a/test/alignas-local.qbe b/test/alignas-local.qbe
new file mode 100644
index 0000000..cff9008
--- /dev/null
+++ b/test/alignas-local.qbe
@@ -0,0 +1,9 @@
+export
+function w $main() {
+@start.1
+	%.1 =l alloc16 1
+@body.2
+	%.2 =l extsw 16
+	%.3 =l urem %.1, %.2
+	ret %.3
+}
diff --git a/test/alignas-member.c b/test/alignas-member.c
new file mode 100644
index 0000000..965e42a
--- /dev/null
+++ b/test/alignas-member.c
@@ -0,0 +1,4 @@
+struct {
+	int x;
+	_Alignas(32) char s[32];
+} s = {123, "abc"};
diff --git a/test/alignas-member.qbe b/test/alignas-member.qbe
new file mode 100644
index 0000000..13aa14f
--- /dev/null
+++ b/test/alignas-member.qbe
@@ -0,0 +1 @@
+export data $s = align 32 { w 123, z 28, b "abc\000", z 28, }
diff --git a/test/alignas.c b/test/alignas.c
index b714d37..a0a7669 100644
--- a/test/alignas.c
+++ b/test/alignas.c
@@ -1 +1 @@
-_Alignas(8) int x;
+_Alignas(32) long x[4] = {1, 2, 3, 4};
diff --git a/test/alignas.qbe b/test/alignas.qbe
index 6dd5505..8758fb2 100644
--- a/test/alignas.qbe
+++ b/test/alignas.qbe
@@ -1 +1 @@
-export data $x = align 8 { z 4 }
+export data $x = align 32 { l 1, l 2, l 3, l 4, }
-- 
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