Don't assume that external global variables are aligned at their preferred

alignment. Only the minimum alignment guaranteed by the ABI may be assumed.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78668 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/InstCombine/align-external.ll

@@ -0,0 +1,22 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | FileCheck %s
+
+; Don't assume that external global variables have their preferred
+; alignment. They may only have the ABI minimum alignment.
+
+; CHECK: %s = shl i64 %a, 3
+; CHECK: %r = or i64 %s, ptrtoint (i32* @A to i64)
+; CHECK: %q = add i64 %r, 1
+; CHECK: ret i64 %q
+
+target datalayout = "-i32:8:32"
+
+@A = external global i32
+@B = external global i32
+
+define i64 @foo(i64 %a) {
+  %t = ptrtoint i32* @A to i64
+  %s = shl i64 %a, 3
+  %r = or i64 %t, %s
+  %q = add i64 %r, 1
+  ret i64 %q
+}