1; A store or load cannot alias a global if the accessed amount is larger then 2; the global. 3 4; RUN: opt < %s -basicaa -gvn -S | FileCheck %s 5target 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" 6 7@B = global i16 8 8 9; CHECK: @test1 10define i16 @test1(i32* %P) { 11 %X = load i16* @B 12 store i32 7, i32* %P 13 %Y = load i16* @B 14 %Z = sub i16 %Y, %X 15 ret i16 %Z 16; CHECK: ret i16 0 17} 18 19; Cannot know anything about the size of this global. 20; rdar://8813415 21@window = external global [0 x i8] 22 23; CHECK: @test2 24define i8 @test2(i32 %tmp79, i32 %w.2, i32 %indvar89) nounwind { 25 %tmp92 = add i32 %tmp79, %indvar89 26 %arrayidx412 = getelementptr [0 x i8]* @window, i32 0, i32 %tmp92 27 %tmp93 = add i32 %w.2, %indvar89 28 %arrayidx416 = getelementptr [0 x i8]* @window, i32 0, i32 %tmp93 29 30 %A = load i8* %arrayidx412, align 1 31 store i8 4, i8* %arrayidx416, align 1 32 33 %B = load i8* %arrayidx412, align 1 34 %C = sub i8 %A, %B 35 ret i8 %C 36 37; CHECK: %B = load i8 38; CHECK: ret i8 %C 39} 40 41