From 28961f9197c8c5356f29fffac0cc322788441759 Mon Sep 17 00:00:00 2001
From: Michael Forney <mforney@mforney.org>
Date: Wed, 27 Oct 2021 19:31:24 -0700
Subject: decl: Use strictest alignment when multiple specifiers are present

This is specified by the last sentence in C11 6.7.5p6.
---
 decl.c                    | 14 +++++---------
 test/alignas-multiple.c   |  1 +
 test/alignas-multiple.qbe |  1 +
 3 files changed, 7 insertions(+), 9 deletions(-)
 create mode 100644 test/alignas-multiple.c
 create mode 100644 test/alignas-multiple.qbe

diff --git a/decl.c b/decl.c
index d31196f..68fc2d0 100644
--- a/decl.c
+++ b/decl.c
@@ -375,15 +375,11 @@ declspecs(struct scope *s, enum storageclass *sc, enum funcspec *fs, int *align)
 			next();
 			expect(TLPAREN, "after '_Alignas'");
 			other = typename(s, NULL);
-			if (other) {
-				*align = other->align;
-			} else {
-				i = intconstexpr(s, false);
-				if (i & (i - 1))
-					error(&tok.loc, "invalid alignment: %d", i);
-				if (i)
-					*align = (int)i;
-			}
+			i = other ? other->align : intconstexpr(s, false);
+			if (i & (i - 1))
+				error(&tok.loc, "invalid alignment: %d", i);
+			if (i > *align)
+				*align = i;
 			expect(TRPAREN, "to close '_Alignas' specifier");
 			break;
 
diff --git a/test/alignas-multiple.c b/test/alignas-multiple.c
new file mode 100644
index 0000000..7fc2199
--- /dev/null
+++ b/test/alignas-multiple.c
@@ -0,0 +1 @@
+_Alignas(8) _Alignas(4) char x;
diff --git a/test/alignas-multiple.qbe b/test/alignas-multiple.qbe
new file mode 100644
index 0000000..fd85074
--- /dev/null
+++ b/test/alignas-multiple.qbe
@@ -0,0 +1 @@
+export data $x = align 8 { z 1 }
-- 
cgit v1.2.3