; A store or load cannot alias a global if the accessed amount is larger then
; the global.
-; RUN: opt < %s -basicaa -gvn -instcombine -S | not grep load
+; RUN: opt < %s -basicaa -gvn -S | FileCheck %s
+target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
-@B = global i16 8 ; <i16*> [#uses=2]
+@B = global i16 8
-define i16 @test(i32* %P) {
- %X = load i16* @B ; <i16> [#uses=1]
+; CHECK: @test1
+define i16 @test1(i32* %P) {
+ %X = load i16* @B
store i32 7, i32* %P
- %Y = load i16* @B ; <i16> [#uses=1]
- %Z = sub i16 %Y, %X ; <i16> [#uses=1]
+ %Y = load i16* @B
+ %Z = sub i16 %Y, %X
ret i16 %Z
+; CHECK: ret i16 0
+}
+
+; Cannot know anything about the size of this global.
+; rdar://8813415
+@window = external global [0 x i8]
+
+; CHECK: @test2
+define i8 @test2(i32 %tmp79, i32 %w.2, i32 %indvar89) nounwind {
+ %tmp92 = add i32 %tmp79, %indvar89
+ %arrayidx412 = getelementptr [0 x i8]* @window, i32 0, i32 %tmp92
+ %tmp93 = add i32 %w.2, %indvar89
+ %arrayidx416 = getelementptr [0 x i8]* @window, i32 0, i32 %tmp93
+
+ %A = load i8* %arrayidx412, align 1
+ store i8 4, i8* %arrayidx416, align 1
+
+ %B = load i8* %arrayidx412, align 1
+ %C = sub i8 %A, %B
+ ret i8 %C
+
+; CHECK: %B = load i8
+; CHECK: ret i8 %C
}